A Real Theremin
|Note: Q1 & Q2 could be replaced with a single CdS LDR light dependant resistor removed from a bathroom night light.|
Etch your own PC
or use the generic board.
Board size 1.6" x 1.8" (40mm x 45mm)
PDF (168k) <= Etch your board using this file.
|Due to the increase in project e-mail, time wise I am unable to give construction support to this circuit.|
You need a black plastic sleeve around the phototransistors to block the
light coming from the sides. This will make the light exposure more directional
toward the phototransistors front lenses . Thanks
Line out can connect to a medium size speaker directly without needing an amplifier.
Experiment: To modulate and drive a super bright LED then replace C2 with a 220 ohm 1/4 watt resistor and properly attach the +/- LED wires to the line out terminals. Pick up the sound remotely up to three feet away using a photo-transistor or a optical remote sensor. This also creates a volume control method.
A triangular waveform which creates a better tone is generated at pins 2 &
6 which is the top connection of C1 of the 555. This can be made useable by
tapping off here and driving the high impedance input of an additional
Op-Amp like a TL082.
Experiment: After the circuit is making noise, connect a wire where Q1, C1 & R2 meet which is pin 2 of the 555 to see if you can get a usable triangular waveform to power your amplifier. This will probably overload our 555 circuit too much.
|Value||Quan.||Radio Shack Part#||Price||Packs||Total||Special Notes|
|CdS Photo Cell||use 1||<= A Substitute for||
|Q2||< Remove from bathroom night light|
|C1||.047 uf||1||272-1068||1.29||1||1.29||Pack has two|
|IC Sockets||8 Pin||1||276-1995||0.69||1||0.69||Use a Socket !|
|PC Board||Generic||1||276-159||2.29||1||2.29||Pack has two or use PDF (168k)|
|V1 Battery||4 AA Holder||1||270-409||1.89||1||1.89||Switch in Battery Holder|
|Line Out||PC Board Term.||1||276-1388||2.29||1||xx||Optional Pack of 4|
|Prices as of Sept. 25, 2004||US Dollars||Total||=||14.30||<=Batteries Not Included (-;|