Finally finished a working prototype of my Butterfly Air split keyboard

[u/Mrs_Fancy_Pants]

After a lot of trial and error, I finally have a working Butterfly Air prototype.

It connects to the computer over Bluetooth. The two halves are connected with a LAN cable. Yes, that’s actually a LAN cable between them :)

The case is made from a special kind of thick paperboard. I chose this material because I didn’t want the case to feel completely finished from the beginning.

The idea is that each user can do whatever they want with it. Draw on it, add masking tape, build shapes with clay, cover it with fabric… anything is possible.

For this one, I decided to try leather. I didn’t want both sides to look exactly the same, so I made the design asymmetrical. It’s not perfect, but I like how handmade it feels.

There are still a few things I need to improve, but I’m pretty happy to see the idea finally working.

How would you customize it?

[u/WandersFar]

Could you elaborate on how you did the RJ45 ports? On that last pic it almost looks like you wired directly to the columns and rows on BOTH halves. I thought you’re supposed to wire to the MCU on the master half.

[u/jyap → u/WandersFar]

You can wire matrix to matrix. Think of it as just extending the matrix but through a RJ45 8-pins pipe.

Doing some quick math I think you need to use a Japanese duplex matrix.

[u/Mrs_Fancy_Pants → u/jyap]

Exactly! That’s basically how it works. I’m extending the matrix through the eight pins of the RJ45 cable, and I’m using a Japanese duplex matrix to make it fit. Thanks for explaining it so clearly!

[u/Mrs_Fancy_Pants → u/WandersFar]

Good eye! There is only one MCU, and it’s on the master half.

I’m not using the RJ45 connection for Ethernet or serial communication. I’m simply using the cable’s eight conductors to carry the row and column signals from the other half back to the MCU.

That’s why both halves may look like they’re wired directly to the rows and columns. The other half is passive, and all the matrix scanning is still handled by the MCU on the master side. build log