If you were at Comic Palooza over the weekend or have attended a recent Raspberry Pi Meetup, you probably played Super Mario World and Mario Kart with a giant game controller. And instead of actuating plastic buttons you simply dipped a finger in a jar of water or simply touched stainless steel arrows.
How It Works
The Raspberry Pi, a thirty dollar computer is running an SNES emulator with Retropie. A MakeyMakey circuit board is then used to convert resistive touch signals to button presses, allowing us to play Mario with non-traditional game controller materials such as water.
Sounds complicated? It's simpler than you think! In fact, the MakeyMakey is a children's invention toy (TxRx offers a Young Makers coding workshop based on the MakeyMakey). It works by converting a completion of a circuit to a keyboard stroke. The board is simply detecting if two conductive materials have made contact, and if it has turns that signal into a keyboard input for a computer. Anything just slightly conductive will work, other things that you can turn into a button include:
- Doggos and Puppers
- Play Doh
- Aluminum Foil
The MakeyMakey works on any desktop or laptop computer, but why use those when you have a much cheaper and portable option - Raspberry Pi.
A Raspberry Pi is a full-fledged computer - I tell kids all the time that the Pi is faster and better than the laptop I used in high school (cue "when I was your age jokes"). And since it’s so affordable at $30, there is a huge maker and eduction community around it. Every distribution of the free linux-based operating system - Raspbian comes with Minecraft and Mathematica. Retropie is simply a specialized flavor of the operating system that allows us to turn the Pi into an emulator for a variety of retro gaming systems:
- SNES (the one we used!)
- Atari 2600
- Commodore 64
How It's Made
This was relatively inexpensive to make. Most of the cost came from the Raspberry Pi and the MakeyMakey board. The rest of the materials are cheap - 1/2 inch copper tubing that were used as standoffs, bolts, mason jars, and cheap plywood from Home Depot, etc.
- 3D CAD drawing made similar to a retro SNES controller made in OnShape. CAD skills are crucial to transferring your ideas to a CNC machine, whether that's a 3D printer, router table, plasma cutter, or mill. TxRxLabs offers a 3D CAD workshop → Fusion 360 CAD
- Routed out plywood in the shape of an SNES controller with CNC wood router.
- Stainless steel arrows cut with a Water Jet through the TxRxLabs Request for Work Service.
- Assembled Plywood cutouts with bolts and copper tubing standoffs, dropped in the stainless steel arrows.
- A Raspberry Pi disk image with RetroPi was set up with ROM with this Retropie tutorial. Configured the controller buttons to the MakeyMakey keyboard.
- Copper Bracelet made in the Jewelry Studio connected MakeyMakey ground with stainless steel conductive thread (special thanks to Ali for making the ground bracelets!)
- Stainless steel keys and Water Jars wired to MakeyMakey circuit board.
This was a super fun project, and I learned that playing a video game with a giant controller doesn't make it any easier!