Radio Shack Photo Theremin
May 12, 2005 @ 6:22 pm
I've done it! My Radio Shack faux theremin (aka photo or optical theremin) is alive!
I was able to follow the wiring digram and get all the parts online from RadioShack.com.
Here is the wiring diagram and parts list (with Radio Shack catalog numbers in parentheses). Thanks to this guy for the wiring diagram and parts list. I've updated some of the catalog numbers with equivalent parts.
B1: 1.5 Volt Battery in Battery Holder (270-401)
C1: 0.1µF 50V Hi-Q Ceramic Disc Capacitor (272-135)
PC1: Cadmium Sulfide Photoresistor (276-1657)
Q1: 2N3904 NPN Transistor (276-1617)
Q2: 2N3906 PNP Amplifying Transistor (276-1604)
SPKR: 8-Ohm Mini Speaker (273-092)
Optional:
J1: Panel-Mount Jack (274-280)
Printed Circuit Board (276-170) or
Modular Breadboard (276-175)
Replies: 7 Comments
nerd. p.s. cool! that rocks!
eliz said on May 12, 2005 @ 7:40 pm
Yeah, it's a long spiral down into total geekdom but so much fun along the way!
Nick Baker said on May 13, 2005 @ 1:31 am
I built one of those back when Radio Shack published the original plans back in the 70s. The only difference in the schematic was that it did not include the jack. I put some in small enclosures and gave them to my brothers Fred and Alex in the 90s and replaced the speaker with earphone jacks and attenuated the earphones so my brothers would not deafen themselves and not drive my dad and step mom insane. A few years ago my brother Alex showed his to a fellow having great trouble building a theremin from a kit. Alex then teased the fellow about the fact his had only a few simple parts.
Rod Sprague said on April 29, 2006 @ 10:37 pm
Yeah, it's pretty simple. Now if I could just figure out how to do a sine wave instead of a square wave...
Nick Baker said on May 1, 2006 @ 11:54 am
Well, good plan. I did make the thing, but it's way too quiet. I tried substituting a 9V battery instead of the 1.5, but it just didn't work at all. Is it supposed to be this quiet? Also, does the volume have anything to do with the capacitor? Because I couldn't get the exact right one, it might be a higher voltage.
Jamie Muir said on March 2, 2007 @ 3:37 pm
Yeah, mine is very quiet too, and it's got nothing to do with the voltage. You'll need an amplifier to take the signal and make it powerful. I plugged mine into the car stereo using a tape deck adapter.
Nick Baker said on March 5, 2007 @ 12:52 pm
I made a similar using a transistor tuj 2n2646 as oscillator and result and very interesting circuit!
nilton cristiano said on September 28, 2007 @ 10:22 pm
