Picture of Bananaphone: A Touch Capacitance Synth
I was recently inspired by a Kickstart project which used Bananas as sensors to control a video game on a PC.  I've done some video game controls using the Propeller in the past, but I thought this would make an interesting synthesizer project.

Introducing: Bananaphone: A Touch Capacitance Synth

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Step 1:

Picture of
Parts List:
  • Your favorite Propeller board.  (I used a Quickstart board w/Terminal Module)
  • A couple packs of alligator jumper wires. (Radio Shack)
  • Nine Bananas (8 notes & 1 to snack on)
  • A 220ohm resistor (Radio Shack)
  • An amplified speaker w/connector
  • The spin source archive

Step 2:

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Make a connection from each of the Propeller's P0-P7 I/O pins to the stem of each banana using the aligator clip jumper wires.

I used a Gadget Gangster QuickTerminal to make my connections to the Propeller Quickstart, but you could just as easily plug jumper wires into the Quickstart's P0-P7 I/O.

You'll also need to hook a 220ohm resistor to P11.  This will become our audio out connection to the amplified speaker.   Connect one side of the speaker to the 220ohm resistor, the other side to Ground.  Using a single resistor as an audio output will be a little noisy, but will work fine for the purposes of this project.  

Here is the recommended audio circuit if you want to reduce the noise and put this project into long term use:

rockerape3 years ago
monkey ate bananas
dreamberry3 years ago
It would be ironic to play "Yes, We Have No Bananas!" with Bananaphone. You made The Humongous laugh. He salutes you.
Did you try to play some Velvet Underground tunes with it ? I think that John Cage will be pleased.
srilyk3 years ago
This, sir, is very Gangster ;)
I'm picturing a "banana contest" in the future.
V1P3 years ago
awesome !!!
I'll keep this instructable printed and locked into a folder just to allow my daughter tell her friends in school that her father can make bananas sing!
merijnvw3 years ago
luckadoo423 years ago
When will I start seeing these in music stores near me?
mrmerino3 years ago
Well that's it. This is the best instructable ever.
birdboy II3 years ago
I'll have to try this with an Arduino.
dennison-m3 years ago
that is amazing! how useful are bananas?! the skins are also great for removing insolubles like metals from water - great for the wastes management industry.
kirtatastan3 years ago