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Build An Optical Theremin

The Theremin That Uses Light

An Instructables by Sacred

Instructables Logo What is a theremin? It is an instrument that can be played without being touched. Traditional theremins use antennas and oscillators to sense a person's hand and generate a tone. Ours will use light instead. Because of this, it is not an actual theremin, it just uses similar principles. As a side note, this is my first instructable, so please be nice.

A Real Theremin

Original Optical Theremin The Original Optical Theremin

Step 1: Gather Materials

This needs very few parts, I made mine for under $20.
Here is what you need:

Part Description Manufacturer Part Number
Phototransistors UT1893-91-0125-R
TLC555 Timer IC TLC555CP
.047µF Capacitor DC.047B
100µF Capacitor RA100/16-R
1MΩ Resistor CF1/4W105JRC
10kΩ Resistor CF1/4W103JRC
Battery Pack (to fit 4 AA) SBH-341-1AS-R
AA Batteries ALK AA (EN91)
Hook-up Wire #9313-0-R
Breadboard WBU-301-R
Small Speaker KWT2340F12L-2E
Wire Stripper JE-2022C-R

Phototransistors These are not LEDs. They are phototransistors.
Make sure you get the right thing!

Resistors 1MΩ Resistors and 10kΩ Resistors

IC Socket The TLC555 IC timer. Mine is an IC socket.
I recommend getting a socket for your chip.

.047µF Capacitor The .047µF capacitor reminds me of chiclets.

100µF Capacitor 100µF Capacitor

Battery Pack and Breadboard My battery pack has an on/off switch built right into it.
Very convenient. Above is a breadboard.

Wire Wire! I got mine from telephone line and when you strip off the outer casing, there's four strands of wire inside.

Speaker My cheap little speaker. It's terrible, but it manages.

Step 2: Putting it Together

This is a really easy circuit to build. Just make sure you follow the directions, and yes, the image came from

RS Optical Theremin

Step 3: The Finished Product and Video

At this point in the game, everything should be working. Congratulations on the build, have fun with it!

Optical Theremin

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