The Ultimate Volume Control

Ultimate 2b 2 Voices	The Ultermen 5 5 Voices
I have researched several types of Optical Volume control: CdS photo resistor volume Photo Cell (most natural) Modulated LED Light Beam listening with a solar cell, photos below.

The Hand Held Solar Cell is a promising Volume & Staccato control concept.

staccato2.mp3 (260k)
Ultermen 5 sample using modulated LED light beams
I am flipping my fingers open & closed in this mp3 sample

My solar cell is sanded to 1/2 size, you should use the full size.
I used a table belt sander to find the maximum it could be reduced.

Place the Solar Cell more towards the tip of your fingers facing outward held in place with a ring or elastic band. This will allow for better Staccato with rapid up & down finger movement. The modulated LED beams should be 12" to 18" below your hand.

The hand mounted Solar Cell output will drive an amplifiers microphone input (sound card) easily, but lacks the power to directly drive a computers amplified speaker input. See the pre-amp below.

You could plug the solar cell directly into a waist mounted wireless microphone transmitter.
I think this is the best all around so you are not tied to anything!

Here is simple pre-amp to boost your solar cell output.
A good generic board to use is the Radio Shack #276-150

Your volume hand can play 12" to 24" away from the Theremins output LED's

Four AA batteries at a 10 ma. drain will last a long time!

This circuit will drive headphones for privacy, computer amplified speakers or your home stereo.
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I designed a solar cell pre-amp PDF with a 100/120 hz notch filter to minimize the hum picked up from incandescent bulb lighting powered from 50/60 hz house wiring. This is accessible on the "Postcard Club Hints & Tips" webpage.

Indirect Halogen Lighting is much better for room lights to minimize hum pickup.

Solar Cell

Lowe's Hardware Store - I removed it from a Malibu sun-powered yard light - Model LZ1 D $9.98

The Malibu Model LZ6 $8.98 USD will work also.

Note: Take the Solar Cell out of the box, tap on it with a coin and make sure it is epoxy, not glass!

The above solar cells are the most sensitive and noise free I found, most others just don't work!

The Radio Shack solar cell 276-124 will not work
The Malibu LZ403 L will not work, it is made of glass.