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A few things lead me on to this:
  • Brian the Robot (see my other Projects); I considered what I could do with it
  • "Circuit-bending" was one thing I considered
  • I recently watched a Youtube video from "Fran's Lab" where Fran talks about "Science Fairs" old and new.

The latter reminded me of the Science Fair I used to have back in the '90s (which never seemed to work right because I got it second-hand off a friend):

I decided to look on ebay for another and found this one going for a good price:

When it arrived I began reading the manual. The first few page explains the various components, one of which is a 'variable Resistor' or 'Control' knob.

I remembered this from the few videos on circuit-bending I had watched; I looked for another specifically about this, and found this one with a good explanation:

Basically, the audio circuit needs to have a resistor which can be swapped out for a variable one, such as is included in the Science Fair... perhaps; since they, like regular resistors, have different ratings and the one used in the example is a "1M pot".

The video also uses the term 'Potentiometer' for the variable Resistor, and I did a quick Google search to confirm if these terms were indeed interchangeable. Strictly speaking, they are not:

A variable resistor is a resistor of which the electric resistance value can be adjusted. ... When a variable resistor is used as a potential divider by using 3 terminals it is called a potentiometer. When only two terminals are used, it functions as a variable resistance and is called a rheostat.

The variable resistor included in the Science Fair kit, according to the illustration in the manual at least, has three terminals, so it can be used as either a rheostat or a potentiometer (pot). In the circuit-bending video he connects the left most terminal and the centre one as viewed from the rear. In this configuration, with only two terminals connected, it is technically a rheostat. There are also digital resistors which are controlled electronically. You can read more here

In the comments section of that video he refers to a book by Reed Ghazala. I looked this up and found a copy of "Circuit-bending: build your own alien instruments" published in 2005. It's pretty pricey, as are others Amazon suggested to me, but I found myself a free download to take a look at. I see it includes "Eighteen Projects for Creating Your Own Alien Orchestra."

Anyway, with my newly received Science Fair, complete with potentiometer and my understanding of how to use it, I dug out my Brian the Robot...


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