It's finally here! This is a very limited-edition kit to build a 4 character split-flap display. Remember those displays that used to be in airports and train stations that made a distinct clack-clack-clack sound as they flipped to show the next departure? Now you can build your own!

You provide an Arduino Uno and a source for 12V and this kit includes all the rest of the parts you need to build your own electromechanical split-flap display. Each module can flip between 40 different flaps, which is enough to show letters, numbers, and a few symbols.

This kit is recommended for intermediate to advanced hobbyists; it requires soldering quite a few components (mostly through-hole, but a few SMD components) and involves other assembly that takes a steady hand and some patience. More details on assembly below, but my general advice would be against trying to build this as your very first experience soldering.

Here's what's in the box:

• 1 Controller PCB (also available for purchase separately)
• 4 Sensor PCBs (also available for purchase separately)
• components for controller and sensor boards (chips, resistors, etc)
• 4 neodymium magnets for calibration
• 4 motors
• 4 sensor cables
• 4 laser-cut MDF module panels
• 160+ professionally die-cut flaps (white) (also available for purchase separately)
• 2 letter sticker packs (black)
• 44+ M4 bolts
• 44+ M4 nuts

Not in the box (you'll need to provide your own):

• Arduino Uno
• 12V DC 2A+ Power Supply (2.1mm barrel jack connector, center positive)

Tools needed:

• Hex key (metric)
• Soldering supplies
• Calipers or metric ruler
• Hobby knife
• Plastic wrap and clear storage container (for applying letter stickers)

This kit includes premium white PVC flaps (the same ones that are available for purchase separately) that were custom ordered and professionally die-cut specifically for these split-flap displays.

IMPORTANT NOTE:

This kit is intended for educational purposes and personal use only. It should not be used in commercial settings or anywhere that will require continuous operation or other heavy use. This is a hobbyist kit and as such the buyer accepts all risks and liability related to its assembly and operation.

How do you build it?

I'm glad you asked, and I'll be straightforward with you: this kit requires significant assembly time. You're looking at probably 15 hours to put the whole thing together, though you can always get one module working before moving onto the others to see some results sooner. The full assembly instructions can be found in the Splitflap v0.5 Assembly Instructions document, but I'll summarize the steps below:

• Solder the hall-effect sensor breakout boards
• Solder the control board, and test the controller and sensors
• Assemble the mechanical components (press-fit MDF pieces with metal fasteners, kind of like IKEA furniture)
• Apply the letter stickers to the flaps
• Attach the flaps, hook everything up, and calibrate each module

About the design

I've loved split-flap displays for a long time but I could never find any for sale, so back in 2015 I set out to design and build my own. As a software engineer professionally and a hobbyist on the side, it was important to me that the design and iteration process was completely open source. It's finally gotten to a stage where I'm happy with the design and excited to share it with you as a kit!

View Interactive 3d Model

Even if you don't buy one of these kits I'd encourage you to check out the open source project - you can always order the parts yourself or even customize the design any way you'd like. Nothing makes me happier than hearing from makers around the world that are tinkering and modifying these designs! And of course I always welcome contributions back to the open source project. If you're curious, this kit corresponds to version v0.5 of the project.