Gaming on a Bus-Sized Keyboard

If you search through Guinness world records, you might be surprised to find that many of the records seem easy to beat or simply don’t exist. Rkade noticed that Guinness doesn’t have an official record listed for “the world’s largest computer keyboard,” though Guinness also states that the current record is 2.5 meters long (about 8.2 feet). Rkade figured that would be easy to beat, so they built this bus-sized keyboard to set the new world record and then used it to play a game.

At its most basic, a computer keyboard is just a bunch of switches connected to a microcontroller through a matrix circuit. If you’re building a normal size keyboard, you can choose from a wide variety of key switches that work with mass-produced key caps. To enlarge that to a size that works with this massive keyboard, Rkade had to get creative. The actual switches are just standard commodity momentary lever-arm switches, but Rkade had to make those work with the gigantic key caps. To accomplish that, he built mechanisms using PVC pipe, 3D-printed brackets, and bungee cords. When someone pushes on a key, one PVC tube slides inside of another like a piston until it makes contact with the switch. The bungee cord acts as a spring.

Rkade had to build 70 of those scaled-up key switches and then 70 key caps. Each key cap is constructed from five pieces of cardboard sheet stuck together with hot glue. Rkade designed the shape of the key caps in Autodesk Fusion 360 CAD to get it just right, and then used that as a template to cut the cardboard. Each cardboard key cap then got a coat of black paint and big alphanumeric legend stickers. The PVC pipe switches fit into a series of holes drilled into a wood frame. That was originally made of simple 2x4 boards, but Rkade had to switch to MDF sheet to avoid warping. Every switch connects to an YMDK keyboard PCB through long Ethernet wires. That YMDK PCB has its own onboard microcontroller to connect to a computer via USB.

To test out the keyboard, Rkade and partner played one of those educational typing games. To fire at an enemy ship, the player must tap the correct keys. That’s easy for an experience typist on a normal keyboard, but very difficult when one has to run 10 feet to reach the next key. Unfortunately, Guinness rejected this as a record entry because their rules are stupid. But as far as we’re concerned, Rkade earned the Hackster World Record for largest computer keyboard.