Simple Electronic Kit #1: 2-Transistor Ribbon Kit

WHAT IS THIS, HOW CAN I MAKE IT?

We're going to show you how to make the world's most bare-bones electronic music instrument – and a bunch of other things, as well.

This instrument is called a 'ribbon controller', but it's also known after its inventor, Paul Tanner, as a 'tannerin'. He called this instrument an 'Electro-Theremin'. That name didn't catch on because this is not a Theremin (the musical instrument you control by moving your hands in the air) even though it sounds like one. You are going to build a sound generator that changes pitch as you slide wires back and forth on a conductive “ribbon” we will make as part of this project..

We also discuss how you can take this same circuit and do many other experiments with things you have around your home.

Brian Wilson and the Beach Boys' song “Good Vibrations” used the magic of Paul Tanner's ribbon controller to make its distinctive sweeping wee-oo-wee sound. Wikipedia has a great page on the history of the ribbon controller: http://en.wikipedia.org/wiki/Electro-theremin

HOW DO I GET ONE?

If you aren't holding one of our “2-Transistor Ribbon Kits” in your hand, keep reading. We'll explain how to make your own kit, or how to get one from us for about the cost of a can of soda.

If you do have the kit, this page will teach you about your kit, show you how to hook it up and talk about several experiments you can do with parts around the house.

EDUCATORS: Click this link for background about using this kit if you're a teacher or group leader. This is a fun & cheap group project.

HOW IT WORKS

• Click this link for a simple description of the basic electronics in this kit, a description of what the parts of this circuit do and how they work together.
  
  
• Click this link for a more technical description of how the circuit operates, including tips on component substitutions.

Briefly, the circuit (called a relaxation oscillator) measures resistance and creates an audio tone to match. The value of the resistance determines how fast a capacitor charges. Once the capacitor gets enough charge, the transistors turn on. This causes the speaker to 'pop' and it also forces the transistors to turn off (relax!). The capacitor then starts to charge up again, repeating the cycle all over again (oscillation).

Enough theory? >>Let's make it!