Posts with «fruit» label

Fruit piano uses a different circuit than the Makey Makey

[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.

You can see there’s a fair amount of circuitry built on the breadboard. Each piece of fruit has its own channel to make it into a touch sensor. 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. You can see the schematic as well as a demo clip after the break.

This use of hardware frees up a lot of your microcontroller cycles. That’s because projects like this banana piano use the timers to measure RC decay. [Hasbi's] setup provides a digital signal that at most only needs to be debounced.


Filed under: arduino hacks, peripherals hacks

MaKey MaKey: how to turn anything into an input-device controller

Jay Silver from SparkFun and Eric Rosenbaum from MIT kickstarted a very nice project, which lets you to convert almost everything into an input-device for your computer.

According to SparkFun:

MaKey MaKey allows you to turn almost any common object into an input-device for your computer. The front side of the MaKey MaKey board has six inputs: up/down/left/right arrow keys, spacebar and a mouse left-click. Using alligator clips you can hook those inputs up to anything that’s even slightly conductive – fruit, play-dough, water, pencil drawings, whatever you can dream up – which becomes a keyboard or mouse input to your computer. So you can play a banana piano, play-dough Mario, or even create custom webcam triggers.

As for the technical side, MaKey MaKey is based on Arduino Leonardo’s bootloader and on ATMega 32u4. From its kickstarter page:

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.

A longer introduction to MaKey MaKey can be found on SparkFun, while a more comprehensive description can be found here, together with some funny videos about its use.

[Via: Sparkfun and Kickstarter]