Monday, 20 August 2007

mtf - week 04 - circuit bending I

For circuit bending I went to a local op-shop and invested in 5 McDonalds toys for a total of 20c each, woohoo. 2 were cars which had nothing but engines in them :( but at least I have 2 engines :) The other 3 all made various noises, and had little speakers/piezo's, so I figured even if they're all crap I still scored!!!

The lion king below makes a growl noise when you push a button, but the entire circuit board is smaller than a $1 coin, which made getting any wet fingers in a difficult proposition. And in terms of exposed circuitry, there's one resistor and a black lump... but still woo hoo said I and started connecting different sections.
I managed to make it pitch up, by bypassing the resistor (first part of the sample). So I decided to try and try variable voltages to its other side. It used 3V as standard, so I decided that if I connected a 3V source in parallel to a 1.5V source it wouldn't be 3V anymore, it made a different noise !!
Then I whacked in the 1Mohm pot in with the voltage (3rd section of mp3), only a very small section of the pot made the lion roar or make any noise so I probably need a lesser pot

here's a sample of the lion king.mp3

or try

Below is a basket ball game, it bipped when you scored a goal, about 1 second after you pushed the button. I managed to make it vary its pitch (bip) but didn't get enough value out of to even bother recording it. I'll have to try it again with some three way connections :)

Below is an xbox, you can see the green cross :)
It made a constant tune which made it a bit easier to do something with, but again just seemed to be able to vary it's pitch. this one also had the largest circuit board so I could get a wet finger in there, and hold a wire on the other end to get a 3 way connection.
And I enjoyed waggling that finger, tremolo :)

Also in the picture is a walkman I pulled apart. I couldn't get the radio to make any noise other than radio (it is only fm with a digital receiver - I think), but looking at the tape mechanism makes me think of manipulating the power to the motor to vary the playback speed .. should be straight forward and quite easy but I need to work out what sort of pot to use for varying the voltage.

here's a sample of the xbox.mp3
you may well notice a baby crying in the background, that's either a) because my fingers were too big for the tiny circuit boards, or b) just another ambient noise that I hardly notice when I'm amazingly engrossed in having fun....

or try

Haines, Christian. MTF - Electronics, Instruments and Improvisation - Outline (Mod 1) (Comp).pdf

pp 3-23, 103-129. Reed, Ghazala 2005, Circuit-bending : build your own alien instruments, Wiley
Publishing, Indianapolis.

pp 59-63. Collins, Nicolas 2006, Handmade Electronic Music: The Art of Hardware Hacking, TFROUTL.

1 comment:

Sebastian Tomczak said...

Hi Edward,
I thought I would let you know that there is a voltage regulation tutorial now up on It should be pretty easy to change the voltage that is applied to a DC motor using this circuit.

Be aware that the circuit can provide up to 1.0 amps without heat sinking or 1.5 amp with adequate heat sinking and that the input voltage must be at least 1.5V above the output voltage.

You can use a single pot to change the regulated output voltage.

If you want to keep the voltage output between certain values, perhaps try placing resistors in series on one or both sides of the pot.

Sebastian Tomczak