Makey Makey guitar
https://www.youtube.com/watch?v=NvunbL9qSUE

Like a 32-bit Makey Makey, Meow Meow is an adorable SAM D21-based dev board that turns anything into a keyboard.

When it launched in 2012, the Makey Makey was the golden child of the maker movement. It was a simple, easy to use board with holes for alligator clips and a USB socket that would present capacitive touch pads as a USB HID device. Thus, the banana piano was born.

The Makey Makey is a device specifically designed to introduce kids to electronics in a way the Arduino can’t match; even with an Arduino, most of the work is with code. If you’re introducing electronics to a class of 10-year-olds, that might be a bit too much.

Now there’s a new Makey Makey on the block. It’s the Makey Makey Go, and it’s the same user experience as the Makey Makey classic made cheaper and much more rugged.

Makey Makey GO: Invent Everywhere, Invent Now!
https://www.kickstarter.com/projects/joylabz/makey-makey-go-invent-everywhere-invent-now

Manolins MaKey MaKey HID Board Deluxe Kit Invention Toy Gift for Kids – Red + White
US$ 34.90
http://dx.com/p/manolins-makey-makey-hid-board-deluxe-kit-invention-toy-gift-for-kids-red-white-240421?r=85273703

While most people spent their holiday playing with toys, Irish maker Conor O’Neill was busy daisy-chaining a Raspberry Pi, MaKey MaKey invention kit, and slices of cheese — yes, cheese — to create a uniquely controlled RC car.

He came across the “i-Racer” a £19.99 (about $32.50) RC car with a Bluetooth radio, rack-and-pinion steering and a rechargeable battery. The car is supposed to be controlled with an Android phone, but O’Neill figured that with a little MaKey MaKey hacking it could be steered with something more unique.

The MaKey MaKey breakout board allows everything from bananas to pails of water to become inputs for a computing device. Paired with a $2 Bluetooth dongle and Raspberry Pi board, the toy race car could potentially be controlled with anything in a pantry. O’Neill took on the grating task of connecting and debugging the various components, sharing his recipe in a very detailed blog post.

MaKey MaKey + Raspberry Pi + iRacer + Bluetooth = Cheese Controlled Car (CCC)
http://conoroneill.net/makey-makey-raspberry-pi-iracer-bluetooth-cheese-controlled-car-ccc/

[Hasbi Sevinç] is using perishable goods in his electronics project. The orange, tomato, and two apples seen above act as keys for the virtual piano. The concept is the same as the Makey Makey which is often demonstrated as a banana piano. This implementation uses an Arduino to read the sensors and to connect to the computer running the piano program.

The signal produced when your finger contacts the food is amplified by transistors connected in a Darlington pair. That circuit drives the low side of a optoisolator transmitter. The receiving side of it is connected the I/O pin of the Arduino.