- on Audio/Video/Photography
- Published in issue 7/2012 on page 21
Simple generation of complex sound effects
These days there are many types of intelligent LEDs available. These LEDs flash or change their colour, slowly or quickly and with different colour combinations. Those LEDs that gradually change from colour to colour (so-called rainbow LEDs) were found to be particularly suitable for an alternative application. They happen to produce incredibly complex sounds when they are connected as shown in this circuit.
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R1 = 100Ohm
R2,R3 = 10kOhm
P1 = 100kOhm
C1 = 22µF 16V
C2 = see text
D1,D2,D3 = rainbow LED, preferably mixed types
1 ‘Elex’ type experimenter’s board