If you want to play a banana, or make a keypad from some drawn pencil marks the MaKey MaKey is the kit for you. This is a Kickstarter but it will be a product since it has raised amazingly raised over a half million dollars over an above the goal of $25,000. Looks like there is a huge demand for this cool item. It is also an open hardware project which means you can see how it was made and make your own or even improve on how it was built.Â
“MaKey MaKey is a printed circuit board with an ATMega32u4 microcontroller running Arduino Leonardo bootloader. It uses the Human Interface Device (HID) protocol to communicate with your computer, and it can send keypresses, mouse clicks, and mouse movements. For sensing closed switches on the digital input pins, we use high resistance switching to make it so you can close a switch even through materials like your skin, leaves, and play-doh. We use a pull-up resistor of 10-50 mega ohms. This technique attracts noise on the input, so we use a moving window averager to lowpass the noise in software, saving money on hardware filtering. There are six inputs on the front of the board, which can be attached to via alligator clipping, soldering to the pads, or any other method you can think of. There are another 12 inputs on the back, 6 for keyboard keys, and 6 for mouse motion, which you can access with jumpers via the female headers. If you wish to use a different set of keys, or otherwise change the behavior of your MaKey MaKey, you can simply reprogram it using the Arduino environment. By cutting a trace on the back of the board, you can disconnect the large pull-up resistors if you want to, which would be necessary in a small minority of Arduino-style projects.”
