Elenco Snap Circuits® Deluxe Sound & Light Combo - Manual (Page 96)

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Project 188 Optical Theremin
A theremin is an electronic musical instrument where
you change the sound by moving your hands around
near it (without touching it); using the tiny changes
your hands have on the electromagnetic field of an
antenna. This circuit is an optical theremin because
instead you adjust the sound by changing the amount
of light reaching a photosensor (the photoresistor).
Project 189 Keyboard Slider
Modify the preceding circuit to match this one. Turn on both slide
switches (S1), and move the lever on the adjustable resistor (RV)
around to change the sound. At some settings there may not be any
sound.
You can play the keyboard (U26) keys while changing the sound with
the adjustable resistor, to get a combination of sound effects. Turn off
the left slide switch to disable the adjustable resistor sound effects.
Build the circuit as shown. Turn on both slide switches (S1), and move
your hand over the photoresistor (RP). You can adjust the sound just
by moving your hand around. See what range of sounds you can
produce, then change the amount of light in the room, and see how
sound the range of sounds has changed. There may not be any sound
if there is too much or too little light on the photoresistor.
You can play the keyboard (U26) keys while adjusting the sound using
the photoresistor, to get a combination of sound effects. Turn off the left
slide switch to disable the photoresistor sound effects.
SCC-350_Manual_Part_B.qxp 7/25/14 2:06 PM Page 40