# flip forward — complete documentation Source: https://www.flipforward.de Generated: 2026-10-21 License: hardware design and documentation CC BY-SA 4.0. flip forward is an open, modular split flap display system. Modules are 116 x 60 mm, weigh about 400 g, run on 12 V and chain together into displays of any size. The mechanical design, firmware and documentation are free; PCBs, kits and flap sets are sold from Germany. Hardware and docs are licensed CC BY-SA 4.0. This file contains every documentation page in full. Each page below is introduced by its URL so answers can cite where a fact came from. --- ## How to build a split flap display URL: https://www.flipforward.de/docs/intro Summary: Free, complete guide to building a split flap display — from one 3D-printed module to a full wall installation. Parts, PCBs, firmware and sourcing. Made in Europe. # How to build a split flap display Split flap displays are the boards that used to greet you at train stations and airports — rows of mechanical flaps that spin and snap into place to show departures, arrivals, destinations. That sound, that motion, that slight impermanence. They disappeared from public spaces decades ago because LCD screens are cheaper and more flexible. But they never stopped being beautiful. And now that 3D printing and cheap stepper motors exist, building your own is genuinely within reach. **flip forward** is a project to make that happen. It covers everything: the mechanical design for individual modules and full installations, the electronics and firmware to drive them, and a platform to control them remotely. It's a side project, built by one person in Germany — not a company, not a product. The goal is to make building this possible for as many people as it can. ![A finished flip forward module in black sheet metal.](https://www.flipforward.de/img/full_module_clean.jpg) ## What you can build The design scales across a wide range of budgets and ambitions. At the low end: a 3D printer, a 28BYJ48 stepper motor, and a handful of screws. That's genuinely everything you need to build a working module. All the models and instructions are here. At the high end: NEMA stepper motors (roughly ten times more powerful, faster, more reliable), sheet metal cases manufactured to spec, professionally printed flaps, and modules mounted on a metal backboard. That's what the displays on the flip forward YouTube channel look like — finished, not prototype. You can start at the bottom and move up piece by piece. The design is the same throughout. ## How it connects Scaling a multi-module installation is clean by design. Modules connect via small [connector boards](https://www.flipforward.de/docs/connector-boards.md) that snap between them, with no cable runs and no wiring harness. Four modules or forty, the installation stays tidy. ![back view of three connected modules using the flip forward connection boards.](https://www.flipforward.de/img/three_module_back.jpg) Every module runs firmware with a small web UI, so a display can be controlled from a browser on your phone over WiFi without installing anything. Two other ways exist. [play.flipforward.de](https://play.flipforward.de) runs virtual twins that behave exactly like real hardware, so a display can be built, its content tested and its alphabet designed before any modules exist. [local-control](https://github.com/flip-forward/local-control) is an open-source desktop app for macOS, Windows and Linux that finds displays on your local network and handles firmware updates, logs and calibration. All three work out of the box and all three are free. [Controlling Displays](https://www.flipforward.de/docs/controlling-displays.md) compares them. ## Using this guide In a hurry? [TL;DR](https://www.flipforward.de/docs/tldr.md) condenses the whole system onto one page. Otherwise the docs follow the order you'll build in. **[Specifications](https://www.flipforward.de/docs/specifications.md)** has the numbers on one page: dimensions, weight, power, temperature, flap counts. *Build a module* covers one module from parts to first power-up: [Sourcing](https://www.flipforward.de/docs/sourcing/), [Flaps](https://www.flipforward.de/docs/flaps/), [Parts Preparation](https://www.flipforward.de/docs/assembly/parts_preparation.md), [Module Assembly](https://www.flipforward.de/docs/assembly/module-assembly), [Electronics](https://www.flipforward.de/docs/electronics/) and [Helpers & Accessories](https://www.flipforward.de/docs/sourcing/helpers.mdx). *Build a display* is everything that only matters once there's more than one: [Planning an Installation](https://www.flipforward.de/docs/planning-installations.md) for enclosures, load, service access and failure behaviour, [Connector Boards](https://www.flipforward.de/docs/connector-boards.md) for the three boards that link modules, and [Wiring & Power](https://www.flipforward.de/docs/display-assembly.md) for backboards, power groups and addressing. *Control* is [Controlling Displays](https://www.flipforward.de/docs/controlling-displays.md): the module's own web UI, play.flipforward.de, and local-control. ## Built in Germany, open to the world flip forward is designed and built in Germany. Parts are sourced from European suppliers where possible, and the shop (coming soon at shop.flipforward.de) will ship PCBs, hardware kits, and flap sets from within the EU — no customs for European builders, fast shipping. Until the shop is live, modules, boards and flap sets can be ordered directly by mail at [hello@flipforward.de](mailto:hello@flipforward.de?subject=Installation%20enquiry). That's also the address for installations, custom alphabets and anything that needs a quote. ## Licensing The hardware design, published parts, and interfaces are licensed under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/). You can use, adapt, and redistribute everything freely — including commercially — as long as you give attribution by linking to [flipforward.de](https://www.flipforward.de) and naming flip forward as the source. The firmware is not open source at this time, as it contains logic tied to play.flipforward.de. Pin-out headers for both board versions and a minimal firmware example will be published in the future. The firmware itself is and will remain free to use. --- ## What a split flap display is and what it takes to build one URL: https://www.flipforward.de/docs/overview Summary: A plain-language explanation of the flip forward project: what a split flap display is, what a build involves, and what it costs. # In plain English This page skips the engineering. The [technical summary](https://www.flipforward.de/docs/tldr.md) has the numbers. ## What this is A split flap display is the mechanical board that used to hang in train stations and airports, where each letter sits on a stack of little cards that flip over until the right one shows. They clatter, they move, and they were replaced by screens decades ago because screens are cheaper. flip forward makes them buildable again. The design, the instructions and the software are published for free, so you print most of a display yourself and buy the few parts you can't print. It's run by one person in Germany, not a company. ## How it works, briefly A display is built from identical boxes called modules, one per character. Inside each is a drum carrying 43 thin plastic flaps, turned by a small motor. A magnet and a sensor tell the module where the drum is, so it can turn to any letter on demand rather than cycling in a fixed loop the way an old flip clock does. Modules clip straight together, so a row has no wiring to build, and only the first module in a row joins your WiFi. It passes instructions along to the rest. ## What it costs Two routes, and the difference matters. **Build it yourself.** Every price on this site, including everything the [display planner](https://www.flipforward.de/calculator/) works out, is the cost of the **parts only**. A module's parts come to roughly €15–90 depending on whether you print the case and flaps or buy them ready-made, and whether you use the cheap motor or the good one. Your own time isn't in that figure, and the first module takes an hour or two to assemble. **Have it built.** Assembled modules and finished displays can be ordered instead. They cost more than the parts, for the obvious reason, and they're quoted per project because flaps, case, power supply, mounting and shipping all depend on what you're building. For scale: for a commissioned installation, budget meaningfully above the parts figure rather than treating it as the price. Either way it undercuts the commercial alternatives, which start around €1,000 for a small finished unit and climb steeply for anything custom. ## What you need For a self-build: a 3D printer, a stepper motor, two small circuit boards, a magnet, a handful of M3 screws per module, and a 12 V power supply for the display. No soldering, no programming, no laser cutter. Flaps and cases can be printed at home or bought. For a commissioned build: a wall, a deadline and an idea of the size. Send those to [hello@flipforward.de](mailto:hello@flipforward.de?subject=Installation%20enquiry) and you'll get a quote back. Before committing either way, [play.flipforward.de](https://play.flipforward.de) will show you a working display on screen, at your size and with your content, without any hardware. ## Asking an AI about the project Everything on this site is also published as one plain text file, so you can hand ChatGPT, Claude or a local model the whole documentation and ask questions in your own words. If your assistant can browse the web: ``` Read https://www.flipforward.de/llms-full.txt in full, then answer my questions about the flip forward split flap display system using only what that document says. If it doesn't cover something, say so rather than guessing. My first question: ``` If it can't browse, or you're running a model locally, download [llms-full.txt](https://www.flipforward.de/llms-full.txt) and attach it to the conversation instead. It's about 95 KB of plain text, well within what current models handle. There's also a shorter [llms.txt](https://www.flipforward.de/llms.txt) listing every page, which some tools prefer. Ask it what a 3 × 12 display would cost in parts, whether a wall recess needs ventilation, or what a print shop needs for custom flaps. One caveat: a model will invent a plausible part number or dimension without hesitating. Check anything you're about to spend money on against the page it came from, or ask on [Discord](https://discord.gg/qCBfZZhWu5). --- ## Split flap displays in five minutes — the flip forward summary URL: https://www.flipforward.de/docs/tldr Summary: The whole flip forward system condensed: module specs, flaps, electronics, the serial protocol, scaling rules, control software and installation constraints. # TL;DR A flip forward module is a 116 × 60 mm split flap unit weighing about 400 g, driven by a stepper motor and an ESP8266 controller board off 12 V, drawing up to 500 mA. Its drum carries 43 flaps of 44 × 30 mm, each 0.3–0.6 mm thick. Modules are identical and chain together into rows of any length. Hardware design and documentation are [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/); the firmware is free but not open source. Full table on [Specifications](https://www.flipforward.de/docs/specifications.md). ## Building a module An FDM printer, a stepper, one controller board, one sensor board, a 4 × 2 mm magnet and about twenty M3 screws. No soldering, no flashing, no laser cutter. The motor is either a 28BYJ-48 (5 V, ~€3) or a NEMA17 `17HS08-1004S` at 20 mm height with lead-only exit, since taller or connectorised versions foul the drum. The controller board differs per motor type, ULN2003A against TMC2209, and can't be swapped afterwards. Parts print without supports in PLA or PETG at 0.28 mm, except the flaps. Parts run €15–30 for a minimal module, €30–40 with a NEMA17, €80–90 with a sheet-metal case and printed flaps, excluding assembly time; assembled modules are quoted separately. First build 45–90 minutes, faster after that. The [display planner](https://www.flipforward.de/calculator/) prices a whole display and lists its parts. Start at [Parts & Sourcing](https://www.flipforward.de/docs/sourcing/), then [Parts Preparation](https://www.flipforward.de/docs/assembly/parts_preparation.md) and [Module Assembly](https://www.flipforward.de/docs/assembly/module-assembly). ## Flaps Print them in multicolor PLA at 0.15 mm layer height, or have them made from plastic sheet, polypropylene being the usual choice. Either way they finish at 0.3–0.6 mm: thicker flaps stop flexing and the mechanism degrades. The standard alphabet is 43 characters set in Oswald, A–Z, 0–9, `€ . ? ! - :` and a blank. Custom alphabets work because homing asks which character is visible rather than assuming a fixed set, and [play.flipforward.de](https://play.flipforward.de) previews one before a print run. Keep the same alphabet on every module so any module can be swapped for any other. A drum needs at least 30 flaps, because the topmost flap draws part of its pre-tension from the ones below; 43 is standard and 52 is the tested maximum. Solid colours instead of characters turn each module into a mechanical pixel, six colours repeated five times giving sub-second changes. Detail on [Flaps](https://www.flipforward.de/docs/flaps/). ## Electronics and protocol One ESP8266 board per module, pre-flashed. First power-up raises an open WiFi network named "flip forward"; a browser handles credentials, homing and alphabet configuration. Serial runs TX of module N to RX of module N+1, so modules are addressed by relative position: `0` is whichever module received the command, `1` is the next downstream, `@` broadcasts. Commands are plain text, `MODULE:COMMAND:ARGUMENT`, reachable over WiFi, HTTP POST to `/command` or serial through the flash board. Command list on [Electronics](https://www.flipforward.de/docs/electronics/). ## Scaling to a display Modules connect through boards that snap between adjacent PCBs, so a row has no cabling. A connection board passes signal and 12 V through. A power break cuts 12 V but keeps ground connected, since the serial chain needs one reference plane. An injector board feeds 12 V in through a screw terminal behind a TI eFuse rated 3 A. At 500 mA per module and 3 A per group, a group holds five modules. The injector feeds both directions, so it sits at the junction after the group's first module, and the boundary to the next group is a power break; a ten-module row is two injectors, one break and six connection boards. Groups don't span rows. Signal is independent of all of it: one chain per row, entering at the first module, which is the row's only WiFi client. Splitting a long row into several shorter chains, each with its own entry point, limits what one controller failure silences. The [display planner](https://www.flipforward.de/calculator/) applies these rules to a given size; [Connector Boards](https://www.flipforward.de/docs/connector-boards.md) and [Wiring & Power](https://www.flipforward.de/docs/display-assembly.md) explain them. ## Control Three clients, all speaking the same protocol. Each module serves a minimal web UI over WiFi for homing and setting a character. [play.flipforward.de](https://play.flipforward.de) adds multi-row displays, images, alternative alphabets and MQTT control from anywhere, and its virtual twins behave identically to hardware, so a display can be configured before it exists. [local-control](https://github.com/flip-forward/local-control) is an open-source Electron app for macOS, Windows and Linux that discovers modules over mDNS/Bonjour, flashes firmware from a file or URL, reads live logs and runs guided calibration, with no internet dependency. Saved playlists exist in none of them yet. Comparison on [Controlling Displays](https://www.flipforward.de/docs/controlling-displays.md). ## Installation constraints 400 g per module, so 26 modules run to about 10 kg before the case; the mounting surface is what needs engineering, and a wall recess carries the load better than a hung cabinet. Modules stay below 38 °C under continuous use, so no ventilation slots or cooling, but leave 3–5 mm above them so warm air escapes rather than collecting in a sealed cavity. Removal is currently from behind, through the three back-case screws into the backboard; front extraction is in development. Keep a spare module. Failures divide the way power and signal do. A power fault trips the eFuse of its group of five and goes no further. A dead controller stops relaying and silences everything downstream in its chain, though not upstream and not other chains. Mechanical faults stay in their own module. More on [Planning an Installation](https://www.flipforward.de/docs/planning-installations.md). ## Getting parts Models, guides and firmware are free. The [shop](https://shop.flipforward.de) is being set up; sample kits go out via [Discord](https://discord.gg/qCBfZZhWu5), and anything larger is quoted by mail at [hello@flipforward.de](mailto:hello@flipforward.de?subject=Installation%20enquiry), per project and net of VAT. State module count, alphabet, what you need supplied and the deadline. Remaining questions on the [FAQ](https://www.flipforward.de/docs/faq.mdx). --- ## Split flap module specifications — dimensions, weight, power & temperature URL: https://www.flipforward.de/docs/specifications Summary: Technical data for a flip forward split flap module — module and flap dimensions, weight, power draw, operating temperature, clearance, flap counts and chain limits. # Module specifications Every number you need to plan a display, get a case built, or hand to whoever signs off on an installation. If something's missing, ask on [Discord](https://discord.gg/qCBfZZhWu5) or by mail and I'll add it. ## Mechanical | | Value | |---|---| | Module front face | **116 × 60 mm** | | Weight per module | **~400 g** (metal case, NEMA17) | | Flap size | **44 × 30 mm**, plus material for the hinges | | Flap thickness | **0.3–0.6 mm** | | Mounting | 3 screw holes on the back of the case | | Motor | 28BYJ-48 (5 V) or NEMA17 `17HS08-1004S`, 20 mm height, lead-only | The flap dimensions aren't negotiable. The entire mechanical design is built around them. Everything else scales. ## Flaps per module | | Value | |---|---| | Standard alphabet | **43 characters** | | Minimum, for reliable operation | **~30 flaps** | | Maximum tested | **52 flaps** | The lower bound catches people out. The topmost flap needs pre-tension to fall cleanly, and that pre-tension comes partly from the other flaps being there. Below roughly 30 flaps the mechanism gets unreliable, so if you only need six colours or ten characters, repeat the set until you're above 30 rather than leaving the drum half empty. 52 is the highest number I've built and tested. It can probably be pushed a little further. ## Electrical | | Value | |---|---| | Supply voltage | **12 V DC** | | Current draw per module | up to **500 mA** under load | | Maximum current per power group | **3 A** | | Modules per power group | **5** (one injector board every 5 modules) | | Protection | Reverse polarity; TI eFuse per injector board (over-/undervoltage, short circuit, overcurrent) | | Linking boards | Connection board, power break, injector board ([details](https://www.flipforward.de/docs/connector-boards.md)) | A single 12 V / 30 A supply, injected at six points, comfortably runs about 30 modules. The [calculator](https://www.flipforward.de/calculator/) does this arithmetic for any display size. ## Thermal & environment | | Value | |---|---| | Maximum module temperature | **38 °C** under continuous heavy use | | Ventilation slots | Not required | | Recommended clearance above modules | **3–5 mm** | I've run modules through long endurance tests and they never got past 38 °C, so no active cooling and no ventilation cutouts are needed. What to avoid is a fully sealed cavity behind the display where warm air has nowhere to go. Leaving 3 to 5 mm above the modules is enough for it to escape. ## Control | | Value | |---|---| | Controller | ESP8266, one per module, all modules identical | | Wireless | WiFi, one entry point per signal chain | | Wired | Serial daisy chain, TX of module N → RX of module N+1 | | Addressing | Relative position in the chain: `N:COMMAND:ARGUMENT`, `@` for all | | Firmware | Pre-flashed, configured in a browser | There's no separate master or controller unit to buy. Every module has the same board, and the first module in a chain is just the one that talks to WiFi and forwards commands to the rest. [Electronics](https://www.flipforward.de/docs/electronics/) has the protocol, [Wiring & Power](https://www.flipforward.de/docs/display-assembly.md) has how signal and power run through a display. --- ## Split flap display parts list & sourcing guide URL: https://www.flipforward.de/docs/sourcing Summary: Full bill of materials for a DIY split flap display module. Where to buy NEMA17 and 28BYJ-48 stepper motors, magnets, and fasteners — with European supplier links. # Split flap display parts list & sourcing guide Let's start by figuring out what you'll need to build a module. *Please keep in mind that this section is still active work in progress.* ## Per-Module Parts, Non-Printed | Part | Quantity | Notes | |------|----------|-------| | Stepper motor (28BYJ-48 or NEMA17) | 1 | | | Sensor Board | 1 | Coming Soon in Shop, Samples available | | Controller Board (either ULN2003A or TMC2209)| 1 | Coming Soon in Shop, Samples available | | Flap Set | 1 | Coming Soon in Shop, Samples available | | Magnet (for home position), 4x2mm | 1 | | | M3x6 Countersunk | 8 | | M3x20 Countersunk | 4 | | M3x16 Countersunk | 3 | | M3x10 Countersunk | 3 | | M3x4 Countersunk | 2 | | M3 Square Nuts | 3 | A multi-module display also needs the boards that link the modules: connection boards, the occasional power break, and one injector board per five modules. Those are per-display rather than per-module, and [Connector Boards](https://www.flipforward.de/docs/connector-boards.md) covers them. > I'm still setting up the online store, and as such, some parts are not yet available directly to order. To make it anyway possible for anyone to start building you can get in touch via Discord and request a sample kit. ### Ordering directly while the shop is being set up For a single module or two, the Discord sample kit route above is the fastest way to get going. For an installation (a dozen modules or more, an event, a gallery piece, a commissioned display) write to [hello@flipforward.de](mailto:hello@flipforward.de?subject=Installation%20enquiry) instead. Assembled modules, connection boards and injector boards can all be ordered directly, and quotes go out net of VAT. Four things decide the quote, so include them in the first mail: how many modules and in how many rows, which alphabet (the standard 43 characters or something custom), what you need from me (bare boards, assembled modules, flaps, or all of it), and when you need it, especially if there's an opening or an event attached. Flaps, cases, power supplies and shipping are quoted separately from the modules, since they vary completely between builds. Custom flaps have the longest lead time of anything in a build. If your alphabet isn't the standard set, start there. ## Motor Details ### NEMA17 NEMA17 basically only specifies the dimension, not the electrical characteristics. What you're looking for is a NEMA17, 20mm height with lead-only connection: that means it doesn't come with a JST connector socket, but the leads exit the case directly. This is super important, as otherwise the stepper is too large to be able to fit inside the drum. The generally working model number is *17HS08-1004S*. Some example links for models that work * Amazon (Affiliate Link): https://amzn.to/48DFBKp * Stepperonline: https://www.omc-stepperonline.com/de/nema-17-bipolar-1-8deg-16ncm-22-6oz-in-1a-3-5v-42x42x20mm-4-draehte-17hs08-1004s (Offers scale pricing) > Keep in mind that minor differences in torque do not matter - we're not running the motor at full load anyway. ### 28BYJ-48 There are plenty of different manufacturers, but they generally all work the same. Please make sure you get the 5V Version, the board is made to work with that. * Amazon (Affiliate Link): https://amzn.to/4w4xdgP > They are virtually always shipped with the driver board - you won't need that, but don't go crazy trying to find a motor without one. ### Metal Case The design of the flip forward module is anchored around a sheet-metal case - black, aluminium and equipped with all the necessary mounting holes. You can either order this (well, soon) or print the model on your 3D Printer - both is fine. For larger installations, I recommend going for the metal case. ## Printed Parts Previous versions of the models used heat inserts in conjunction with metal fasteners. This added significant time to building the modules without providing outsized benefits. The current version relies on M3 Screws being directly screwed into the plastic - this is robust enough for both the Drum and joining the Back Case with the Front Case Part. You do not need Heat Inserts at all for building your Display module. ### Parts Orientation and Print Settings All parts have been designed to print without supports. You can use the .3mf below for a quick start and to check parts orientation. The models are quite robust and can be printed at "rough" layer heights - .28mm is usually fine, even for the smaller details, like the inner holes of the drum. Material wise, PLA and PETG both work fine - just make sure the PETG is properly dried before printing, as the models do not take well too blobs and other artifacts. ### Front Case The main housing component of the display module. You'll be able to order this from the shop as a powder-coated aluminium case, or you can take the model and print it – just make sure you orient it so that the user-facing part is on the build plate (i.e. the opening down). It contains all the necessary mounting holes for assembly. ### Back Case This is the part that connects the Front Case with an eventual back plate, which is used for bigger installations. This is also where the controller PCB is mounted on the finished thing. ### Back Case, End Piece This is the part that connects the Front Case with an eventual back plate, which is used for bigger installations. This is also where the controller PCB is mounted on the finished thing. This version has the plastic wall extending all the way to the front of the module, closing it visually. This is for the end piece of an installation. ### Flap Stop Arrests the motion of the flaps after they've turned over. Optional, but highly recommended. ### Front Guide Actually, this is a crucial part to ensure the flaps are always turning over at a defined point with some more momentum than gravity alone could supply. Mounted with 2 M3x4mm screws. ### Main Drum The main drum consists of two parts - a flat one, and one that I coined "Kraken Part", because it looks a bit alien. There's two small notches, one on each part, and they need to align - this ensures that the flaps later are actually symmetrical. The Kraken part slides onto the Shaft of the NEMA-Stepper (or a a 28BYJ-48) and is fixed using a nut and a screw. This is the part that needs a dialed in printer. Make sure the tiny holes are clean from oozing or other unwanted plastic, as having extra material there will prevent clean movement. Also, the Kraken Part might look a little excessive but it's symmetric design is actually required to ensure there's no asymmetric warping when printing. ### NEMA17 Cable Holder This part is installed on the side of the NEMA17 Stepper to ensure that the motor cables are neatly pushed down to be super close to the case, and not flying around and interfering with the drum and the flaps. ### Sensor and Cable Holder This part has two purposes - it fixes the dedicated sensor board that carries a hall effect sensor precisely in place, while also containing 4 cutouts for the NEMA17 motor cables. They get pressed in there so that they're secure during operations. This part also has an alternate version that doesn't require pushing in cables into a groove - and it's preferred for when you're using the BYJ motor. ## Using a 28BYJ-48 instead of a NEMA17 You already some some alternative versions of parts depending on which motor type you have above, the essential one you'll need is this here - it's an adapter that enables you to mount the BYJ on mounting holes that are intended for a NEMA. The part includes some cable guiding as well. --- ## Flaps for split flap displays URL: https://www.flipforward.de/docs/flaps Summary: How to make flaps for a split flap display — 3D printing in multicolor PLA, UV or screen printing on plastic sheet, custom alphabets, colour flaps, and free .3mf downloads. # Flaps for split flap displays > Flap Maker (tip): Generate your own flap set as PDF and 3MF in the [Flap Maker](https://www.flipforward.de/flaps). The flaps are what makes a split flap display — split flap. Each module uses a full set of flaps mounted on a drum, flipped by the stepper motor to show the desired character. There are three ways to get them, and they're all valid: | Route | Material | Thickness | Good for | |---|---|---|---| | **3D print them** | Multicolor PLA | 0.3–0.6 mm | Anyone with a multicolor printer. Free files below. | | **Have them printed** | Plastic sheet, e.g. PP | 0.3–0.6 mm | Custom alphabets, other languages, larger runs, colour flaps | | **Buy a set** | — | — | Getting going without a printer or a print shop | Two things are fixed whichever route you take. Flaps are **44 × 30 mm** plus material for the hinges, and they finish at **0.3–0.6 mm** thick. The hardware design is built around both, and the thickness is what lets a flap flex. ## Alphabet Each standard set of flaps contains **43 characters**, set in the typeface Oswald: ``` A B C D E F G H I J K L M N O P Q R S T U V W X Y Z € 0 1 2 3 4 5 6 7 8 9 . ? ! - : [blank] ``` The last character is a blank flap — when the drum rotates to this position, the display appears empty. ### How many flaps a drum needs | | Flaps | |---|---| | Minimum for reliable operation | ~30 | | Standard set | 43 | | Maximum tested | 52 | The minimum surprises people. The topmost flap needs pre-tension to fall cleanly, and it gets part of that from the other flaps being there. Below roughly 30 the mechanism becomes unreliable, so if your display only needs ten characters or six colours, repeat the set until you're above 30 rather than running a half-empty drum. 52 is the highest count I've built and tested. It can probably be pushed a bit further. ### One alphabet for the whole display It's tempting to give each module only the letters it needs. The third module only ever shows five different characters, so why print 43? Don't. Identical alphabets make every module interchangeable: positions can be swapped, and a spare fits anywhere in the display. Give each module its own flap set and a failure means rebuilding that specific drum instead of swapping in the spare you keep in a drawer. The saving is small, the cost when something breaks isn't. ### Custom alphabets The firmware doesn't care what's on your flaps. Homing works by asking which character is currently visible, so any custom set works: other languages, symbol sets, logos, colours. You can build and preview a custom alphabet on [play.flipforward.de](https://play.flipforward.de) before committing to a print run. Alternative alphabets are supported there, and a virtual twin behaves exactly like a hardware display, so what you see in the browser is what you'll get on the wall. If you need the cut and print templates for a print shop, ask on [Discord](https://discord.gg/qCBfZZhWu5) or by mail and I'll send them over. ## Colour flaps and pixel displays A module doesn't have to show characters. Fill the drum with solid colours and each module becomes one large mechanical pixel. A grid of them renders low-resolution images and animations. Stay above the 30-flap minimum. With six colours, print each colour five times. The repetition isn't waste, it's what makes the mechanism work. It also makes the display fast. With five copies of every colour spread evenly around the drum, the nearest instance of any colour is never far away, so a colour change lands in well under a second. A 43-character alphabet can't do that. ## 3D printing flaps Flaps can be printed at home on any multicolor-capable 3D printer. I've used PLA and that worked very well so far. The files are split across three plates; each `.3mf` contains the geometry for multiple flaps. Make sure you import them as a multi-part object, not as separate objects — otherwise they'll just fall down to the build plate and not, well, work. ### Filament Assignment The `.3mf` files do not include filament presets — you need to assign the correct filament to each object in your slicer. Each flap consists of three parts: | Object name | Filament | |-------------|----------| | `*_base` | **Black** | | `*_front` | **White** | | `*_back` | **White** | In your slicer, each object will show up with a name like `f00_base`, `f01_front`, etc. — assign the filament slots accordingly. ### Print Settings Getting the right layer height is critical — each printed flap needs to end up at a total thickness of **0.3–0.6 mm**. If the flaps are much thicker, they won't flex, and that will lead to poorer overall function. It's imperativ that the flaps are thin. If you have issues that the white is bleeding through black layers, try tuning your flow rate or changing the filament. | Setting | Value | |---------|-------| | Layer height | **0.15 mm** | | Print type | Multicolor | > tip: Make sure your first layer is well calibrated. Since the flaps are so thin, even small deviations in the first layer will have a noticeable effect on the total thickness. ## Flaps from a print shop If you need an alphabet the printed files don't cover (another language, a custom symbol set, brand colours) a print shop is the way to go. This is how the flaps on the finished displays are made. ### Material and thickness Polypropylene works well, at the same **0.3–0.6 mm** as a printed flap. Getting this wrong is the most common mistake. A 1 mm sheet feels reassuringly solid and is exactly wrong, because the flaps have to flex for the display to work reliably. Thin and slightly floppy is correct. ### Printing method UV printing and screen printing both work. The awkward part is the colour rather than the process: white on black is hard to source, and plenty of shops will quote for it and then struggle to deliver good opacity. Ask for a sample before ordering the full run. A scheme that runs dark on light is much easier. ### Cutting The outline trips up most quotes. Die punching is the traditional answer and gives clean hinge cutouts at volume, but tooling costs money and shops are often reluctant for small runs. Laser cutting works well for a one-off installation, and it's what I'd try first if a die punch stalls the schedule. Send the shop the cut and print files rather than a description. Ask on [Discord](https://discord.gg/qCBfZZhWu5) or by mail and I'll send them. ### Budget the time Flaps are the slowest manual step in a build. The module itself goes together quickly. Assembling and mounting a set of flaps takes roughly five minutes per module and doesn't get much faster with practice, so a 30-module display means a couple of hours of flap work. It's also the part with the longest lead time, so plan the print run early. ## Downloads ### Plate 1 ### Plate 2 ### Plate 3 --- ## Parts preparation — split flap display assembly URL: https://www.flipforward.de/docs/assembly/parts_preparation Summary: What to prepare before assembling a split flap display module — magnet orientation, set screw installation, and flap mounting. # Parts preparation — split flap display assembly In this chapter we'll go over everything that should be done before you actually screw your module together. ## Magnet Orientation The small magnet that goes into the flat part of the drum has to be oriented correctly for the hall sensor to register it correctly. In order to determine this orientation, the firmware comes with a small "Hall Debugging" feature. To use this, you have to * Connect the sensor PCB to the controller PCB * Power the controller PCB (using a 12V Power Source and a power injector board) * Either * Connect a Phone or Computer to the "flip forward ####" WiFi * Point your browser to http://splitflap.local * Enable Hall Debugging * Or simply press the button on the controller PCB three times, that also enables the Hall Debugging Mode. What happens is that the LED on the ESP8266 will light up if the hall sensor detects the magnet. Once you've determined the right "up" orientation, mark it using a sharpie or press-fit it right away into the flat part - and then do the test again. It's a hassle to remove the whole assembly again if you get this wrong, so make sure to get this right. Either disable the Hall Debugging Mode in the Web UI or power cycle the controller (i.e. turn it off and on again.) ## Set Screw Installation In order to fix the drum to the motor shaft, there's a slot for an M3 nut and a matching bolt that are used to create a solid connection between the drum and the motor. You should install this screw and nut before any further steps and make sure that the screw is almost reaching into the slot where the motor shaft goes. After installation, you can simply fix it then using 2-3 rotations. > If you install the standard flaps so that the A aligns with the notch on the drum, the set screw is generally between L/M - so if you remove those flaps, you can easily tighten or lose it. ![Image of the main drum with the nut and set screw shown.](https://www.flipforward.de/docs/../static/img/set_screw.jpg) ## Flap Installation Generally I recommend to install the flaps last - complete the module assembly, and then add the flaps to the already installed drum. The drum has, on both sides, a small rectangular notch - that's where the A goes. While the homing mechanic couldn't care less where the flaps start and end, it's making it easy to locate other features (like the set screw) - but of course, feel free to deviate from that best practice. The original reason for the notch was to avoid misaligning flaps. The PVC flaps, as well as the 3D Printed ones, are generally robust. You can bend them a bit so they snap in place. ![Image of the main drum with two flaps installed, showing the intended alignment between the flaps and the drum.](https://www.flipforward.de/docs/../static/img/drum_alignment.jpg) --- ## How to assemble a split flap display module URL: https://www.flipforward.de/docs/assembly/module-assembly Summary: Step-by-step assembly instructions for a single split flap display module. Covers motor mounting, drum assembly, sensor installation, case closing, and flap installation. # How to assemble a split flap display module Step-by-step instructions for assembling a single split flap display module. A complete module consists of the printed case, the drum with flaps, a stepper motor (NEMA17 or 28BYJ-48), the controller PCB, the sensor PCB, and the flap set. **Assembly time:** roughly 45–90 minutes for a first build. Subsequent modules are faster once you know the sequence. Use the interactive 3D viewer below to follow along — click **Next** to advance through each step, or use the arrow keys. Detailed notes on each step are in [Parts Preparation](https://www.flipforward.de/docs/assembly/parts_preparation) and the [Sourcing guide](https://www.flipforward.de/docs/sourcing/). --- ## Split flap display electronics — ESP8266 PCB, firmware & protocol URL: https://www.flipforward.de/docs/electronics Summary: Split flap display electronics — PCB design, ESP8266 firmware, WiFi control, daisy-chain wiring, and the serial protocol for driving multiple modules. # Electronics — PCB, firmware & wiring Flip forward display modules are powered by a small controller board that contains an ESP8266, a stepper driver and plenty of auxiliary electronics and connectors. > The boards for controlling 28BYJ-48 and for controlling NEMA-Type steppers are physically different. You need to choose a motor type before getting a board and you can't swap motor types without changing the controller board. ![The TMC2209 version of the flip forward controller board](https://www.flipforward.de/img/pcb.jpg) The design goal of the controller board is to make a single module easy to control, and to let that scale to bigger installations without extra hardware. All boards come flashed with the flip forward firmware build for the stepper driver on the board - TMC2209 for NEMA-Type steppers or the ULN2003A for 28BYJ48 Steppers. ## Installation The board fits on the back part of the case. There's two designated mounting holes and you can use M3 Screws that go directly into the plastic. ### 28BYJ-48 For this variant, you only have to connect the 5-PIN JST Connector of the motor to the connector on the top right of the board. That's really it. ### TMC2209 / NEMA In this variant, you have to connect the motor wires to the screw terminal on the board. Use the below picture for the color order. > Please note that there isn't really a standard for the colors on NEMA motors, but so far, this color scheme has consistently worked. If it doesn't for the motor you're using, please reach out. ![The TMC2209 version of the flip forward controller board](https://www.flipforward.de/img/tmc_cable_out.jpg) ## Connectivity The board runs on 12V, and the power is injected either through one of the JST-XH 5 Pin-Connectors at the bottom of the board or through the dedicated connector for Flashing firmware. We recommend either using a standard flip forward connection board to inject power or using the Flash Board with Barrel Connector to inject 12V. Each module draws up to 500mA and the daisy chaining has been dimensioned so that 3A can safely flow through the modules. Recommendation is to never power more than 5 modules from the same power injector. The module is protected against reverse polarity, but the easy way to not inject power the wrong way around is to pay attention to the text on the PCBs - if it's all oriented the same way between connectors and the boards, you're fine. Those power groups are also the fault containment for the whole display. Each injector board carries a TI eFuse, so an overcurrent or a short stays limited to the five modules behind it. [Planning an Installation](https://www.flipforward.de/docs/planning-installations.md) covers what that means for a permanent installation, and how a failed module affects the ones downstream of it. The [specifications page](https://www.flipforward.de/docs/specifications.md) has the voltages and currents. ## Talking to the module There are two designated ways to send commands to the module - using a serial connection through the dedicated Flash Board, or by connecting through WiFi. ### Flash Board When connecting the Flash Board it's imperative to connect both the 12V barrel jack, as well as USB. The Flash Board will show up as "flip forward programmer" - and you can flash the ESP or connect to it using a Serial Monitor - the baud rate of the firmware is at xxx. ### WiFi When power is applied, the LED of the ESP-Module shortly flashes in blue. After a few moments, a new WiFi is going to appear that bears the name "flip forward". You can connect to that and open a browser - it'll greet you with a setup page where you can home the module, configure the alphabet and so on. You can also enter your WiFi credentials there - the module will then connect to the specific WiFi. If the WiFi connection can't be established, the module will fall back to having an open WiFi that can be used to set new credentials. > note: WiFi is automatically terminated when commands are received via Serial - this is to ensure that there's not 50 open WiFis in the daisy chain setup of a larger installation. Once connected, the module is reachable using any browser using its IP Address as a host, allowing you to interact with the module using the same web page. ### Serial-over-HTTP There's a second option, which is to use HTTP POST from a HTTP client (Curl, Postman) to directly send commands to the module. All requests have to go to `http://HOSTNAME/command`, as POST, with a form field called `command` containing the command to be sent - like `0:BLINK` to make the receiving module blink its LED. An example in curl looks something like this ``` curl --request POST \ --url http://IP/command \ --header 'content-type: application/x-www-form-urlencoded' \ --data command=@:SHOWWORD:%m ``` This option is great for writing integrations. ## Protocol Design The protocol that the modules use to communicate between each other is almost human readable, simple and efficient. The good news is that there are facilities that ensure that it's always human writable. ### Making modules addressable A lot of open source split flap designs use established protocols, such as I2C, to communicate to multiple modules. We're taking a very different approach - the daisy chaining in the flip forward world is simply achieved by hooking up the transmitting serial pin of Module N to the receiving serial pin of Module N+1. In turn the transmitting serial pin of Module N+1 is connected to the receiving serial pin of Module N+2 and so on. That also means that communication is unidirectional. Individual modules are simply addressed by their relative position. If my first module is connected to a computer via Serial, issuing a command for module `0` means: the first module. Issuing a command for module `1` means the next module (N+1). ### Message format The messages that are sent between modules always have the same format: - One magic byte to indicate the begin of a protocol message - Two bytes that contain the length of the message - One byte module index - Payload The payload itself encodes the command, and this part is always human readable: ``` 0:COMMAND:ARGUMENT ``` The first part is the module the command is intended for. `0` means the relative first module, `1` the second and so on. If you want to run the same command on all modules (i.e. run a firmware upgrade), you can replace that with `@` and it'll be executed by all modules receiving it. Some commands do have an argument, others do not, see the list below. If you're sending commands directly to the module, either via Serial or WiFi/HTTP, you can simply use the format above and the firmware will translate it into the protocol version. The protocol is intended to be really fast - the messages actually transmit instantaneously, while still retaining some form of readability - we want debugging to be fast and not needing other tools than a HTTP client or a serial monitor. ### Supported Commands | Name | Meaning | Arguments | Comments | |------|---------|-----------|----------| | `BLINK` | Blinks the diagnostic LED | — | For diagnostics | | `DISPLAYCHAR` | Moves the display to show the indicated character | Char to display, e.g. `c` or `C`. Will automatically uppercase. | — | | `SHOWWORD` | Shows the word in the argument | — | Always addressed to all displays (`@`) for performance reasons. | | `MAXSPEED` | Indicates the speed at which the display moves after accelerating | 1–200 | Start high, go lower if something doesn't work. | ### Examples | What | How | |------|-----| | Make the receiving module blink | `0:BLINK` | | Make all connected modules blink | `@:BLINK` | | Make the N+1 module blink | `1:BLINK` | ## Homing and First Use The only mandatory step is to home the display after assembling it. This is the process of teaching the firmware where the magnet is in relation to the characters in your display. The firmware supports a homing mechanic called **smart homing**, since it takes up to 5 samples and asks you which character you're seeing - and then determines the homing position based on that. It's more robust than taking a single character and the flap point (i.e. the point at which the character changes). You start smart homing by issuing: ``` N:SMARTHOME:3 ``` (or `5` if you want 5 samples, but three is usually fine) You then wait until the display comes to a rest and type which character you're seeing: ``` N:SMARTHOME_CHAR:X ``` You do that for every sample - the display will then automatically move to Blank (if that's in your character set) and you're done. This mode is also supported on the diagnostic web page. --- ## Helpers & Accessories URL: https://www.flipforward.de/docs/sourcing/helpers Summary: Helpers and accessories that can make the assembly or operations of a module easier. # Helpers & Accessories You don't need them, but some of those might just come in handy. ## Flap Sorting Box One of the more tedious parts of assembling a split flap display is getting the flaps sorted and ready to be inserted into the drum. This sorting box (of which you'll need two) come in quite handy: They make it easy to place and remove flaps from it, and you can also put them on a piece of paper with the correct flap order to help with sorting. ![Sorting Box in action, filled with flaps.](https://www.flipforward.de/docs/../static/img/sorting_box.jpg) --- ## Planning a split flap installation — mounting, service access, load & failure behaviour URL: https://www.flipforward.de/docs/planning-installations Summary: What to settle before building a permanent split flap installation — enclosure and recess design, weight and load, service access, thermal clearance, failure behaviour and spares. # Planning an installation This page covers the decisions you make before anything gets built: how the display sits in the room, how you reach a module that stops working, what it weighs, and what happens when something fails. It's written for permanent installations in galleries, offices, lobbies and exhibitions, and for the architects, carpenters and engineers who have to sign them off. For how the boards and modules connect, see [Wiring & Power](https://www.flipforward.de/docs/display-assembly.md). The raw numbers are on [Specifications](https://www.flipforward.de/docs/specifications.md). ## Enclosure: cabinet or recess Two approaches keep coming up, and both work. A cabinet, meaning a wooden or metal box hung on the wall, is the straightforward option. It's self-contained, it can be built off-site, and it can be taken down and moved. The catch is weight. At roughly 400 g per module, a 26-module display is around 10 kg of modules before the case, and a cabinet solid enough to carry that on a wall is carpentry work rather than a weekend job. A recess in the wall, a shallow niche the display nests into, is the quieter result and mechanically the easier one. The wall carries the load instead of a hanging box, cable runs and the power supply disappear behind it, and there's nothing to swing when the flaps move. A display of moving flaps has real mechanical momentum, and a rigid mounting surface handles that better than a suspended cabinet. Whichever you choose, plan around three things: the [clearance](#clearance-and-heat) above the modules, where the power supply lives, and how you reach a module later. ## Service access Assume that at some point one module has to come out. There are two ways to build for that. Rear access is how it works today. Modules are screwed to a backboard through the three holes in the back case, and the backboard has to be reachable from behind to take a module out. That's fine for a cabinet and fine for a wall you can get behind. It's a problem for a sealed recess. Front extraction, pulling a module out through the face of the display without touching the back, is in development. The connector boards between modules double as part of the retention mechanism, so a module can be released and lifted out from the front. If you're planning a recessed installation where the back will be permanently closed up, get in touch before you build. That's the case it's being designed for. > Keep spares (tip): Order one or two modules more than your display needs. A spare that can be swapped in during an exhibition is worth far more than the module costs, and it's the reason to keep [one alphabet across all modules](https://www.flipforward.de/docs/flaps/#one-alphabet-for-the-whole-display). ## Weight and load Roughly 400 g per module, plus the backboard, case and power supply. | Display | Modules | Module weight | |---|---|---| | 12 characters | 12 | ~4.8 kg | | 26 characters | 26 | ~10.4 kg | | 4 rows of 20 | 80 | ~32 kg | Beyond a handful of modules, it's the mounting surface rather than the modules that needs engineering. ## Clearance and heat Modules need no ventilation slots and no active cooling. Under continuous heavy use they stay below 38 °C. What they do need is somewhere for warm air to go. Leave 3 to 5 mm above the modules, and avoid a fully sealed cavity behind the display where heat accumulates with no path out. A recess open at the top, or a cabinet with a gap along its upper edge, is enough. ## What happens when a module fails Every serious installation asks this first, so here it is plainly. Power is contained. Injector boards cut the 12 V rail into isolated groups of at most five modules, each with its own eFuse. A short, an overcurrent or an overvoltage event shuts down that group and nothing else, so a fault can't cascade across the display. Signal is a chain. Commands travel from the WiFi entry module down the row, module to module. A module whose controller has failed outright stops passing commands downstream, so everything after it in that chain goes quiet. Everything before it, and every other chain, keeps running. That trade-off is adjustable, and for a large or hard-to-reach installation you should adjust it. Every module can connect to WiFi independently, so a long row can be split into several shorter chains, each with its own entry point. Ten chains of ten modules mean a single failure takes out at most ten modules instead of a hundred. It costs nothing but WiFi clients and a little setup. Mechanical failures stay local. A jammed drum or a bad flap set affects only that module, which keeps passing signal and power through as normal. ## Running unattended A display in a public space shouldn't need a laptop babysitting it. A module keeps its configuration and its content, so after a power cut the display comes back up on its own with nobody opening a browser. For content that changes, push updates to the [webhook endpoint](https://www.flipforward.de/docs/display-assembly.md#receiving-updates-via-webhook) on play.flipforward.de from whatever system holds the data, or drive the display from the [local-control desktop app](https://www.flipforward.de/docs/controlling-displays.md#local-control) if the installation has to stay off the internet entirely. One thing to plan around honestly: local-control can rotate several messages on a repeat interval, but saved playlists don't exist yet. A named sequence you can store, reload and hand over is the next feature on the list, not a shipped one. If your installation depends on rotating content, [tell me early](mailto:hello@flipforward.de?subject=Installation%20enquiry). ## Getting help with a specific space If you're planning an installation and want a second pair of eyes on the mounting, the segmentation or the schedule, or you need someone to talk your gallery's engineer through the numbers on this page, write to [hello@flipforward.de](mailto:hello@flipforward.de?subject=Installation%20enquiry). Sample modules can be sent out so a mounting mock-up can be tested before the real order goes in. --- ## Split flap connector boards — connection, power break and injector URL: https://www.flipforward.de/docs/connector-boards Summary: The three small PCBs that link split flap modules — the connection board, the power break variant, and the injector board with its eFuse and 12 V terminal. # Connector boards Modules aren't wired to each other. They're bridged by small boards that snap directly between the connectors of two neighbouring module PCBs, so there's nothing to wire and nothing to crimp. Four modules or forty, the back of the display stays flat. Three boards do this job. They share an outline, four mounting holes and the same pair of 5-pin JST-XH sockets, so any of them drops into any position in a row. What differs is what each one does to the power rail, and that difference decides the layout of a large display. ## The connection board ![The flip forward backboard connection board, a small black PCB with two 5-pin JST-XH sockets and traces running straight across between them.](https://www.flipforward.de/img/connector.jpg) The default, and the one you'll use most. Completely passive: the serial line (TX of module N to RX of module N+1) and the 12 V rail both run straight across to the next module. You can see it on the board itself, where the traces go from one connector to the other with nothing in the way. Use one between every pair of neighbours that should share power. One comes included with each controller PCB. ## The power break ![The same connection board, silkscreened POWER BREAK, with the power trace between the two connectors interrupted.](https://www.flipforward.de/img/connector_powerbreak.jpg) Same board, same footprint, one deliberate difference: the 12 V trace between the connectors is cut. The silkscreen says POWER BREAK so you can tell the two apart at a glance, which matters when you're behind a forty-module display working out why one section is dark. Only 12 V is cut. Ground runs straight through, deliberately, because the serial chain needs a common reference plane along its whole length. Break ground along with the supply and the two sides of the board would be talking without agreeing on what zero volts means. Every boundary between two power groups is a power break. That falls out of how the injector works: it feeds 12 V in both directions, so the module to its left is powered as well as the modules to its right. Without a break at the group boundary, the group before it would be fed too. ## The injector board ![The flip forward backplate injector board, a black PCB with a green 12 V screw terminal, an eFuse and supporting components, marked MAX 3A.](https://www.flipforward.de/img/injector.jpg) Power enters the display here. The green screw terminal takes your 12 V supply and feeds the rail in **both** directions, left and right. That's deliberate. A one-directional injector would need a second variant for the module at the start of a row, and two nearly identical boards is exactly the kind of thing that gets mixed up on a workbench. One symmetric board covers every position. It's the only one of the three with components, and they earn their place. The TI eFuse guards its group against overvoltage, undervoltage, shorts on the bus and overcurrent, and it trips fast and locally. MAX 3A is printed next to the terminal because that's the real limit of everything behind it. Signal passes through as on the other two boards. ## Which board goes where | | Connection board | Power break | Injector board | |---|---|---|---| | **Signal** | Passes through | Passes through | Passes through | | **12 V rail** | Passes through | **Cut** | **Fed from the screw terminal** | | **Ground** | Passes through | Passes through | Passes through | | **Components** | None | None | eFuse, protection circuitry | | **12 V input** | — | — | Screw terminal | | **Marked** | — | `POWER BREAK` | `MAX 3A` | | **Availability** | One with each PCB | Ordered separately | Ordered separately | Each module draws up to 500 mA and a group is rated at 3 A, so a group holds five modules. Within a group, the injector sits at the junction **after the first module**, so it feeds that module backwards and the remaining four forwards. The junction where one group meets the next takes a power break. Everything else is a connection board. A ten-module row therefore looks like this: ``` [1]─INJ─[2]─C─[3]─C─[4]─C─[5]─BREAK─[6]─INJ─[7]─C─[8]─C─[9]─C─[10] ``` Two injectors, one power break, six connection boards. The [display planner](https://www.flipforward.de/calculator/) works this out for any size: enter rows and columns and it draws the groups and counts the boards. Signal ignores all of it. It runs as one continuous chain from the row's WiFi entry module to the end, straight through all three board types. Power and signal are independent systems that happen to share a connector; [Wiring & Power](https://www.flipforward.de/docs/display-assembly.md#signal-and-power--two-independent-systems) shows how that plays out across a whole display, and the [calculator](https://www.flipforward.de/calculator/) gives you the counts for a specific size. > Why segmenting is worth the boards (tip): Isolated groups keep a fault local. A short or an overcurrent shuts down five modules and trips their eFuse instead of propagating across the display. On a permanent installation that's the difference between one section going dark and the whole wall going down. [Planning an Installation](https://www.flipforward.de/docs/planning-installations.md#what-happens-when-a-module-fails) covers the rest of the failure behaviour. ## Mounting All three boards have four mounting holes and sit against the backboard, held between the two modules they connect. Screw them down along with the modules and the row becomes one rigid assembly, which also means a board can be released and swapped without disturbing its neighbours. Watch the orientation. Every board is silkscreened the same way up, so if the text on the connector boards and the module PCBs all reads in the same direction, the polarity is right. Modules are protected against reverse polarity anyway, but reading the text is faster than checking the wiring. --- ## Building a split flap display installation — backboards, wiring & power URL: https://www.flipforward.de/docs/display-assembly Summary: Combine split flap modules into a full installation — backboard mounting, connection and injector boards, power distribution, module addressing, and software setup. # Building a complete installation Once your individual modules are built and homed, you can combine them into a multi-module installation. This page covers backboard mounting, the two kinds of boards that link modules, how signal and power flow through a row, how to address individual modules, and the software setup for a finished installation. ## Mounting modules to the backboard Each module case has **three dedicated screw holes on its back** — designed specifically for attaching modules to a backboard. A custom-fitted backboard is the recommended way to hold everything together: it keeps spacing uniform, makes the assembly rigid, and makes it easy to take individual modules out for maintenance. ![Three modules mounted side by side, back view showing the screw holes and connector boards](https://www.flipforward.de/img/three_module_back.jpg) Screw the modules directly to the backboard using those three holes. The exact backboard material and dimensions depend on your display size — wood, aluminium sheet, and laser-cut acrylic all work well. ## The boards that link modules Neighbouring modules in a row are linked by small PCBs that snap directly between the connectors of two adjacent module PCBs, so there are no loose cables. Three of them exist, sharing one outline and one footprint, and although they look almost identical from the outside they do very different things to the power rail. Be sure not to mix them up: | | Connection board | Power break | Injector board | |---|---|---|---| | **Signal** | Passes through | Passes through | Passes through | | **12 V** | Passes through | **Cut** — ends a power group | **Fed** from the screw terminal | | **Ground** | Passes through | Passes through — common reference for the signal | Passes through | | **12 V input** | — | — | Screw terminal for the supply | | **Safety electronics** | — | — | TI eFuse: over-/undervoltage, short-circuit and overcurrent protection | | **Availability** | One included with each PCB | Ordered separately | Ordered separately | Photos of all three, and how to choose between them, are on [Connector Boards](https://www.flipforward.de/docs/connector-boards.md). A **connection board** is a passive bridge: it carries the serial data line (TX of module N → RX of module N+1) and the 12 V power rail straight through to the next module. Use one between every pair of neighbours that should share power. An **injector board** is where power enters the display. It provides a screw terminal for a 12 V supply and feeds the rail in both directions, so it sits at the junction after the first module of its group, powering that module backwards and the rest of the group forwards. The boundary to the next group is a **power break**, which is what keeps the two groups electrically separate. Each injector board also carries a TI **eFuse** that guards its power group against overvoltage, undervoltage, shorts on the bus, and overcurrent — ensuring the rating of any component on the bus is never exceeded. Signal passes through unaffected; only the power rail is interrupted. ## Signal and power — two independent systems Two distinct systems run through these boards: **signal** and **power**. They share the same physical connectors but follow completely different rules, which is why a connection board and an injector board can look alike yet behave so differently. Use the sliders above to explore how different configurations change the layout. For a specific display size, the [display planner](https://www.flipforward.de/calculator/) counts the boards and the power groups you'll need. ### Signal: one continuous chain per row Signal runs uninterrupted through every module in a row, regardless of how power is segmented. The first module in the row connects to your WiFi network and acts as the entry point for commands; all commands addressed to downstream modules arrive via WiFi and are forwarded along the chain using a very fast serial protocol. Downstream modules don't need their own WiFi credentials — a 10-module row only needs one WiFi client. Different rows are fully independent: each row is its own signal domain with its own WiFi entry point. A 40-module display with four rows of ten has four WiFi clients and four independent serial chains. The design also supports a more granular approach. Every module has the same PCB and can independently connect to WiFi — so you could split one long row into multiple independent segments, each with its own WiFi entry point. This increases fault isolation: a problem in one segment doesn't affect others. This flexibility is intentional and can be useful for very large installations or in environments where network reliability matters. ### Power: isolated groups of at most 3 A Power is shared along the row too, but it is **segmented into groups** by the injector boards. Each group must draw less than 3 A in total, and groups are electrically isolated from each other. This isolation matters for two reasons: - A short circuit or overcurrent event is contained to a small number of modules and triggers a fast shutdown in the affected group only. - A fault can't cascade across the whole display. Each module draws up to 500 mA under load, so the practical rule is one power group **every 5 modules**, since five modules approach the 3 A group limit. Each group gets one injector after its first module, and each boundary between groups gets a power break. [Connector Boards](https://www.flipforward.de/docs/connector-boards.md) shows the pattern. ## What happens when a module fails The answer differs for power and for signal, which is worth knowing before you build something permanent. Power faults stay in their group. Each injector board isolates at most five modules behind its own eFuse, so a short, an overcurrent or an overvoltage event shuts down that group and nothing else. A fault can't travel across the display. A dead module breaks the chain behind it. Signal is forwarded module to module, so a module whose controller fails outright stops relaying commands, and everything downstream of it in that chain goes quiet. Modules upstream of it, and all other chains, carry on as normal. That's the trade-off of a daisy chain, and it's adjustable. Every module can act as a WiFi entry point, so a long row can be split into several shorter independent chains. Ten chains of ten modules means a single controller failure takes ten modules offline instead of a hundred. On large or hard-to-reach installations that's worth the extra WiFi clients. Mechanical failures stay local. A jammed drum or a bad flap set affects only that module, which keeps passing signal and power through untouched. ## Taking a module out again Modules are screwed to the backboard through the three holes in the back case, so removing one currently needs access to the backboard from behind. That's fine for a cabinet or an open wall, and a problem for a display recessed into a sealed wall. Front extraction is in development: releasing a module and lifting it out through the face of the display, with the connector boards doubling as the retention mechanism. If you're planning an installation where the back will be permanently closed up, [get in touch](mailto:hello@flipforward.de?subject=Installation%20enquiry) before you build. Either way, order a spare module or two. Swapping one in takes minutes, rebuilding one during an exhibition does not. [Planning an Installation](https://www.flipforward.de/docs/planning-installations.md) covers the rest of the questions a real room raises: enclosures, load, clearance and service access. ## Addressing individual modules Because signal is one continuous chain, every module in a row is individually addressable through the row's single WiFi entry point. Modules are addressed by their **relative position** in the chain, using the command format from the [serial protocol](https://www.flipforward.de/docs/electronics#protocol-design): ``` N:COMMAND:ARGUMENT ``` - `0` addresses the module that receives the command — for a command sent to the row's WiFi entry, that's the first module. - `1` addresses the next module downstream (N+1), `2` the one after that, and so on. - `@` addresses **all** modules in the chain at once — useful for things like firmware upgrades or showing a whole word. So to make the fourth module in a row blink its LED, you send `3:BLINK` to the first module — for example via the Serial-over-HTTP endpoint: ``` curl --request POST \ --url http://IP_OF_FIRST_MODULE/command \ --header 'content-type: application/x-www-form-urlencoded' \ --data command=3:BLINK ``` The first module relays the command down the chain until it reaches its target. The full list of supported commands lives on the [electronics page](https://www.flipforward.de/docs/electronics#supported-commands). ## Configuring a multi-row display with play.flipforward.de A single display that spans multiple rows is configured at [play.flipforward.de](https://play.flipforward.de). There, you can: - Define which rows belong to the same logical display and in what order. - Map character positions across rows so the display behaves as one coherent unit. - Send text updates and see them reflected across all rows simultaneously. - Render images across the grid, and build and preview alternative alphabets. play runs virtual twins alongside hardware displays, and the two behave identically, so a multi-row layout can be built and tested in the browser before the modules for it exist. It's the intended way to drive displays with more than one row. The [local-control desktop app](https://www.flipforward.de/docs/controlling-displays.md#local-control) does the same job without an internet connection, and [Controlling Displays](https://www.flipforward.de/docs/controlling-displays.md) compares the two. ## Receiving updates via webhook Once your display is set up on play.flipforward.de, you can integrate it with external systems using the **webhook** endpoint. Send an HTTP POST to your display's webhook URL with the text you want to show, and the platform pushes the update to all rows. This is useful for dashboards, arrival boards, notifications, or anything else that benefits from a programmatic trigger — no open browser tab required. --- ## Controlling a split flap display — web UI, play.flipforward.de and local-control URL: https://www.flipforward.de/docs/controlling-displays Summary: The three ways to drive a flip forward split flap display — the built-in module web UI, play.flipforward.de virtual twins and hardware displays, and the local-control desktop app. # Controlling your display Underneath everything sits one idea: a display is driven by short text commands, addressed by position. ``` 0:DISPLAYCHAR:A ``` Module `0` is whichever module received the command, `1` is the next one downstream, `@` is all of them. That's the whole interface. Every tool below is a client speaking that protocol, so nothing here does anything you couldn't do yourself with `curl`, and nothing locks you to one piece of software. The full command list is on the [electronics page](https://www.flipforward.de/docs/electronics/index.md#supported-commands). Three ways to drive a display exist today. They aren't stages you graduate through. Pick whichever fits what you're doing. | | Module web UI | play.flipforward.de | local-control | |---|---|---|---| | Where it runs | On the module itself | In the cloud | Desktop app, macOS, Windows & Linux | | Needs internet | No | Yes | No | | Finds displays | You type the IP | After pairing | Automatically, on your network | | Homing & alphabet setup | Yes | Yes | Yes | | Multi-row displays | No | Yes | Yes | | Images & custom alphabets | No | Yes | — | | Firmware updates, logs | No | No | Yes | | Cycling through several messages | No | — | Yes, on a repeat interval | | Saved playlists | No | — | Not yet | | Open source | — | — | [Yes](https://github.com/flip-forward/local-control) | | Best for | First power-up, quick checks | Getting going fast, remote control, testing without hardware | Installations, maintenance, working offline | ## The module web UI Every module runs its own small web interface. On first power-up it opens a WiFi network called "flip forward". Connect to it, open a browser, and you get a setup page. Once you've given it your WiFi credentials, the same page is reachable at the module's IP address on your network. It's deliberately minimal: home the module, configure the alphabet, set a character. No playlists, no multi-row displays. Enough to get a module working and to check one that's misbehaving, and it's always there, with no app, no account and no internet. ## play.flipforward.de [play.flipforward.de](https://play.flipforward.de) is the easiest way to get going, and the only one that works without hardware. It runs two kinds of display, and this is the part worth understanding: virtual twins and hardware displays behave identically. A virtual display in the browser and a wall of real modules take the same content, the same alphabets and the same commands. So you can design a display, build the alphabet, load an image and get everything right before a single module exists. When the hardware arrives, the same configuration drives it. Virtual displays let you build and test any display size in the browser, with sound. Pair a module with your WiFi and play drives it remotely over MQTT from anywhere. Multi-row displays get defined here too, including which rows form one logical display and how characters map across them. Images render across a grid of modules, alternative alphabets can be previewed before you have flaps printed, and [webhooks](https://www.flipforward.de/docs/display-assembly.md#receiving-updates-via-webhook) push updates in from any external system. It's free, and it's the intended way to drive displays with more than one row. ## local-control [local-control](https://github.com/flip-forward/local-control) is a desktop app for macOS, Windows and Linux, and it has quietly become the way most people run their displays. It's open source, and installers for all three platforms are on the [releases page](https://github.com/flip-forward/local-control/releases). It finds displays by itself. Point it at a network and it discovers every module via mDNS/Bonjour (service type `splitflap`), so there are no IP addresses to write down and no pairing step. Where discovery is blocked, add a display by IP instead. From there it does the things the other two can't. Firmware gets flashed from a local `.bin` file, served by a small HTTP server the app runs on your own machine, or from a public URL, so updating an installation doesn't mean touching each module one at a time. A live activity log records every command sent and every request received, which is how you debug a module that won't behave. A guided calibration flow walks through aligning a module's flaps step by step. Individual modules can be told to reboot, blink, home or show a single character. Text can be sent as a list that cycles on a repeat interval. It's also fully local. Nothing leaves your network, and nothing depends on an internet connection or on play.flipforward.de being reachable. For a gallery, an office, or anywhere the network is closed off, that's usually what decides it. [Download local-control](https://github.com/flip-forward/local-control/releases/latest) for macOS (Intel and Apple Silicon), Windows, or Linux as `.AppImage` or `.deb`. The source is on [GitHub](https://github.com/flip-forward/local-control) if you'd rather run it with `npm start`. > Saved playlists aren't there yet (note): local-control can cycle through several messages on a repeat interval, which covers a lot of installations. What doesn't exist is a proper playlist: a named sequence you can save to a file, reload later, and hand to someone else. That's next on the list. If you're planning an installation that depends on rotating content, [say so](mailto:hello@flipforward.de?subject=Installation%20enquiry), because it helps to know what shape it needs to take. ## Building your own The protocol is simple enough that writing your own control software is a small job. Send an HTTP POST to a module and it forwards the command down the chain: ``` curl --request POST \ --url http://IP_OF_FIRST_MODULE/command \ --header 'content-type: application/x-www-form-urlencoded' \ --data command=3:BLINK ``` Every tool above uses that same path. Home Assistant, a cron job, a shell script or your own app all work equally well. The [electronics page](https://www.flipforward.de/docs/electronics/index.md#talking-to-the-module) has the commands and the serial route. --- ## Split flap display FAQ URL: https://www.flipforward.de/docs/faq Summary: Common questions about building, buying, and operating split flap displays — with honest answers on cost, difficulty, tools, and how flip forward compares to alternatives. # Frequently asked questions Honest answers to the questions that come up most often about building, sourcing, and running split flap displays. --- ## Cost & Difficulty ### How much does it cost to build a split flap display? A single module costs roughly **€15–90 in parts**, depending on the motor and case you choose. Every figure on this site, including the [display planner](https://www.flipforward.de/calculator/), prices parts only: your own assembly time isn't in it, and neither is anything bought ready-assembled. | Build path | Parts cost per module | |-----------|----------------| | Minimal (28BYJ-48, 3d-printed case, 3d-printed flaps) | ~€15–30 | | Mid-range (NEMA17, 3d-printed case, 3d-printed flaps) | ~€30–40 | | Finished (NEMA17, sheet-metal case, screen printed flaps) | ~€80–90 | A four-character display runs roughly **€60–360** in parts, depending on which path you take. Ordering modules assembled costs more than the parts and is quoted per project, since flaps, case, power supply and shipping depend on the build. Either way it stays well under the commercial alternatives, which start at ~€1,000 (Vestaboard) and scale to €10,000+ for custom installations from specialised vendors. ### How hard is it to build? **Intermediate.** If you've assembled 3D-printed parts and connected a microcontroller before, you'll be comfortable. Specific things that are *not* required: soldering, programming, a laser cutter. The main variable is 3D printer calibration — flaps need to come out at 0.3–0.6 mm total thickness. A well-tuned printer makes this easy; a poorly tuned one will cause problems. First build takes **45–90 minutes per module**. Subsequent modules are faster. There's also an active community on discord, supporting the build journey for every maker. ### What tools do I need? - An FDM 3D printer (any bed size that fits the parts — roughly 150×100 mm minimum) - M3 screwdriver or hex key set, as well as a small philips driver for the NEMA module. - A 12V power supply (any 12V, 2A+ supply works for a single module) That's it for a minimal build. No soldering iron, no oscilloscope, no laser cutter. --- ## Motor & Parts ### Which stepper motor should I use — 28BYJ-48 or NEMA17? **Start with a 28BYJ-48** if you want the cheapest build (~€3) or are just testing. It produces a working display and is available everywhere. **Upgrade to a NEMA17** (specifically model **17HS08-1004S** — the 20 mm height, lead-only version) for faster, more reliable motion. This is what the displays on the flip forward YouTube channel use. Cost is ~€8–12 per motor; Stepperonline ships to Europe at scale pricing. The 20 mm height matters: taller NEMA17s won't fit inside the drum. ### Do I need a laser cutter? No. The flip forward design is fully 3D-printer-first. All structural parts print without supports. For permanent installations, the cases can be ordered as powder-coated sheet-metal — but that's optional, not required. ### Can I print everything on a standard FDM printer? Yes. PLA and PETG both work. All parts are designed to print without supports at 0.28 mm layer height. The flaps are the only precision-critical prints: they must be 0.3–0.6 mm thick, which requires a 0.15 mm layer height and well-calibrated first layer. --- ## Firmware & Control ### Does the firmware need to be programmed? No. The controller PCB ships pre-flashed. On first power-up, the module broadcasts a WiFi network called "flip forward". Connect from your phone or laptop and the setup page handles homing and configuration. No IDE, no uploads, no code. ### How do I control a split flap display? Three ways, all free, all speaking the same simple command protocol: 1. **The module's own web UI.** Every module serves a minimal page over WiFi for homing, alphabet setup and setting a character. No app, no account, no internet. 2. **[play.flipforward.de](https://play.flipforward.de).** The easiest route once a module is paired with your WiFi: multi-row displays, images, alternative alphabets, and remote control over MQTT from anywhere. Virtual twins and hardware displays behave identically, so you can build and test a display before you own one. 3. **[local-control](https://github.com/flip-forward/local-control).** An open-source desktop app for macOS, Windows and Linux that finds every display on your local network via mDNS/Bonjour. It also does firmware updates, live logs and guided calibration, and works with no internet connection at all, which is why it's become the most-used option for permanent installations. [Installers are here](https://github.com/flip-forward/local-control/releases). You can also send commands via HTTP POST from any HTTP client (curl, Postman, Home Assistant, etc.). Full detail on [Controlling Displays](https://www.flipforward.de/docs/controlling-displays.md). ### Can a display cycle through several messages? Partly. local-control can send several messages that rotate on a repeat interval, and a module keeps its configuration through a power cut and comes back up without anyone touching it. What doesn't exist yet is a saved playlist: a named sequence you can store as a file, reload later and hand to someone else. That's next on the list. For content that changes on a schedule today, push it in from outside via the [webhook endpoint](https://www.flipforward.de/docs/display-assembly.md#receiving-updates-via-webhook). ### Can I customize the character set? The standard set is **43 characters**: A–Z, 0–9, and a handful of symbols (€ . ? ! - :) plus a blank. The homing firmware learns positions by asking which character is currently visible, so you can print a custom flap set with any alphabet and the firmware adapts. The 3D-printable flaps are designed in the typeface Oswald, but the `.3mf` files can be modified. ### What size are the flaps, and can I have them printed instead? Flaps are **44 × 30 mm** plus material for the hinges. That one isn't adjustable, because the whole hardware design is built around it. They finish at **0.3–0.6 mm** thick either way, printed or cut from plastic sheet (polypropylene works well). Flaps have to flex for the display to work reliably, and a 1 mm sheet is far too rigid. UV printing and screen printing both work. The hard part is sourcing white on black, so ask for a sample before committing to a run. The [flaps page](https://www.flipforward.de/docs/flaps/) has the detail. ### How many flaps fit on one module? The standard alphabet is 43 characters, and **52 is the highest count I've tested**. There's a minimum too, which catches people out. Below roughly **30 flaps** the topmost flap loses the pre-tension it needs to fall cleanly, so if your display only needs ten characters, repeat them until the drum holds at least 30. ### Can I build a colour or pixel display? Yes. Fill the drum with solid colours instead of characters and each module becomes one large mechanical pixel. Stay above the 30-flap minimum (six colours, printed five times each) and you get a useful side effect: with every colour repeated around the drum, the nearest instance is never far away, so a colour change completes in well under a second. ### Can it show a clock or live data? Yes. Unlike a flip clock, a split flap module is addressable, so clocks, countdowns, arrival boards and dashboards all work. Program the content directly, or push updates to your display's [webhook endpoint](https://www.flipforward.de/docs/display-assembly.md#receiving-updates-via-webhook) from whatever system has the data. --- ## Scaling Up ### How many modules can I chain together? As many as you like. The serial daisy-chain protocol has no firmware module limit. In practice: **inject power every 5 modules** (each module draws up to 500 mA; the chain is rated at 3A continuous). A 20-character display needs 4 power injection points. ### What does a full installation look like? Modules snap onto a backplate via the back case mounting holes. For larger displays, a metal rail system keeps everything aligned. The connector boards that link modules handle both power distribution and serial communication — there are no loose cables between modules. ### How much does a module weigh? Roughly **400 g**, with a metal case and a NEMA17 motor. A 26-module display is about 10.4 kg of modules before the backboard, case and power supply. For anything larger, it's the mounting surface rather than the modules that needs thinking about. The module front face is 116 × 60 mm, and the [specifications page](https://www.flipforward.de/docs/specifications.md) has the rest of the numbers. ### Do the modules need ventilation? No. Under continuous heavy use they stay below **38 °C**, so no ventilation slots and no active cooling. Do leave **3–5 mm of clearance above** the modules, and avoid a fully sealed cavity behind the display where warm air has nowhere to go. ### What happens if one module fails? Power faults are contained. Each injector board isolates at most five modules behind its own eFuse, so a short or an overcurrent shuts down that group and nothing else. Signal is a daisy chain, so a module whose controller fails outright stops relaying commands and everything downstream of it in that chain goes quiet. Modules upstream, and every other chain, keep running. Any module can act as a WiFi entry point, so a long row can be split into several shorter independent chains: ten chains of ten means one failure takes out ten modules instead of a hundred. A mechanical failure, a jammed drum or a bad flap set, only ever affects that one module. ### Can I pull a module out from the front? Not yet. Modules are screwed to a backboard through three holes in the back case, so today a module comes out from behind. Front extraction, with the connector boards doubling as the retention mechanism, is in development. If you're planning a recessed installation with a permanently closed back, [get in touch](mailto:hello@flipforward.de?subject=Installation%20enquiry) before you build. [Planning an Installation](https://www.flipforward.de/docs/planning-installations.md) has more. --- ## Comparing Alternatives ### How does flip forward compare to scottbez1's splitflap project? Both are open-source DIY split flap display projects, and both work well. The differences: | | flip forward | scottbez1/splitflap | |--|--|--| | Structure | 3D-printed + sheet metal option | Laser-cut MDF or acrylic | | Lettering | 3D-printed multicolor flaps | Vinyl stickers | | Controller | Custom PCB (ESP8266) | Custom PCB (ESP32) | | Firmware | Pre-flashed, WiFi setup + MQTT | Open source, requires flashing | | Best for | FDM printer, no laser cutter | Laser cutter access, full open source | If you have a laser cutter and want maximum openness, Scott's project is excellent. If you have an FDM printer and want a polished out-of-the-box experience, flip forward is the better fit. ### Why not just buy a Vestaboard? Vestaboard is a finished product starting at ~€1,000 for a small unit. It's a real split flap display and the fastest path to something on your wall with no building involved. flip forward is for people who want to build it themselves — because of the process, the price, the customizability, or because they want a display size that Vestaboard doesn't offer. The two aren't really addressing the same audience. ### What's the difference between a split flap display and a flip clock? A flip clock cycles through a fixed sequence (hours and minutes) in one direction, forever. A split flap display is **addressable** — it can jump to any character in its alphabet on demand. This requires a home sensor (a hall effect sensor detecting a magnet in the drum) so the firmware knows where the current position is and can motor to the right character. Flip clocks don't need this because they always move forward. --- ## Sourcing in Europe ### Where can I buy parts or kits in Europe? The flip forward shop at [shop.flipforward.de](https://shop.flipforward.de) (launching soon) will sell PCBs, hardware kits, and flap sets — all shipped from Germany. No customs fees for European buyers. In the meantime: - All 3D models and documentation are free to download - Stepper motors and hardware are linked with European suppliers in the [Sourcing guide](https://www.flipforward.de/docs/sourcing/) - Sample kits are available on request via the [Discord server](https://discord.gg/qCBfZZhWu5) ### Can I buy assembled modules instead of building them? Yes, and for installations that's usually the sensible route. Assembled modules, connection boards and injector boards can be ordered directly by mail at [hello@flipforward.de](mailto:hello@flipforward.de?subject=Installation%20enquiry) while the shop is being set up. Quotes are per project and net of VAT. Everything around the module varies: flaps (especially with a custom alphabet), the case, the power supply and shipping are quoted separately, because they depend on what you're building. Tell me the module count, the alphabet and roughly when you need it, and you'll get a number back. --- ## Community mods & remixes for flip forward URL: https://www.flipforward.de/docs/sourcing/community_mods Summary: Community-made and remixed parts for the flip forward split flap display, including lonci's fully 3D-printed case — compatible with both 28BYJ-48 and NEMA17 builds. # Community Mods Here you find parts created or modded by the community. Usually their authors are also on the flip forward discord, and they're just as eager to get feedback as we are. > Please note that we don't provide support for community mods - but feel free to discuss them in our discord. ## Full 3D Printed Case by lonci Lonci is the first person to ever receive a flip forward kit - and he went right into action, tuning parts and coming up with great ideas on how to improve the existing parts. ![image of Loncis Remix 1](https://www.flipforward.de/docs/../static/img/lonci_1.jpg) His 3D Printed Case come with a number of benefits, like a dedicatd cable guide, integrated flap guide and flap stop as well as a nice finish. Compatible with both the BYJ and the NEMA Version of flip forward. ![image of Loncis Remix 2](https://www.flipforward.de/docs/../static/img/lonci_2.jpg) --- ## flip forward changelog URL: https://www.flipforward.de/docs/changelog Summary: Significant updates to the flip forward split flap display project — new and improved 3D-printable parts, model fixes, and documentation changes. # Changelog You'll find significant changes to the project and project files here. ### 12.7.2026 Adds Flap Sorting Box / Accessories section. ### 12.6.2026 * Reworked the Building Displays section into "Building Installations" — clearer structure, sharper distinction between connection boards and injector boards, and a new section on addressing individual modules ### 8.6.2026 * Added Section on Building Displays * Major new Kraken Part for BYJ (much better fit) ### 25.5.2026 * Improved Flap Guide * Additional End-Piece Back Case Part * Added our first community part! * Added installation instructions to the Electronics section ### 4.5.2026 * New front case with better support on the right side. ### 3.5.2026 * New universal back case with alignment guides ### 2.5.2026 * Updates Front Case model for better printability * Added built plate * Added sourcing instructions for the motors ### 26.4.2026 Changed Back Case and Drum Models to move from Heat Inserts to screwing the fasteners directly into plastic. Same mechanical properties, smaller BOM. ---