ten dalla keyboard

[lifeis@song]

so i bought this ten dollard keyboard at target hoping to bend it (im new to all of this by the way) and im not sure that i can get good sounds out of it. its got two really small circuits . one circuit has like one capacitator on it and a whole bunch a solder points that control all of the keys and pitches and stuff. the other circuit board has two transistors, some more capacitators and resistors. to which points should i conecct wires, and how would i go about putting in a pitch control and or looping knob? do i use both circuits in order to do this?

[mikmo]

This sounds like a very very simple circuit. Does'nt it have a little round black blob chip on it ?

To find the pitch resistor (if there is one) try to play sounds, and touch different points on the circuit board, if you hear a change in pitch you found it.

Go here http://www.anti-theory.com/soundart/   read and learn.

But most of all just dive in and experiment.

[lifeis@song]

what about a loop? is it possible to do that some how?

[mikmo]

There's really only one way to find out. Try

Try  to check the "underside" of the circuit board to see if theres a black blob chip.

One way that you can sometimes make a circuit loop is to use the audio out signal to retrigger one of the switches that makes a sound.

[lifeis@song]

what do you mean by black blob? there is some sort of bloby looking thing that is black, there is nothin attached  to it though. al there is no imput or out put

[Timoty777]

Actually ive heard a couple of people recommend using the "black blob" chip and I have one keyboard that i cant seem to get any cool sounds out of, but it has a black blobby chip, what exactly does one do with those? Could someone post pictures on how to bend the blobby chips?

[mikmo]

Black blob chips are really called COB chips (Chip On Board), its basically like an ordinary IC, except it is made on the actual circuit board and covered with a "blob" of black epoxy. This is a cheap way of mass producing a circuit board with a specific (but limited) set of functions.

There will usually be coppertraces on the circuit board going to the black blob, these can be treated like the pins on any ordinary IC.

Theres no "general bending rules" for black blob chips, as allways there's trial and error.

Many black blob chip toys does not have too much bending potential, because the functionality you would typically spread over 2 or more IC's in a traditional design is now all under the black blob where it is inaccessible to bending.

This doesen't mean that they are useless for bending, try to take a look at my site http://www.mikmo.dk most of my instruments are actually of the black blob type. There's also examples of what you can do to expand the possibilities of balck blob toys by adding a little circuitry of your own.

Frequently there is a pitch resistor close to the blob. This is especially true if the toy is of the type that plays back samples. This resistor controls the playback rate and can be replaced with a potentiometer to give you pitch up / down control. sometimes it's not close to the blob. Sometimes it's not there at all.


Hope this helps a bit.