Elenco Snap Circuits SOUND ® User Manual
Page 41
Project 50
Super Optical
Keyboard Echo for
Headphones
Headphones or Stereo
Speaker (not included)
WARNING:
Headphones performance varies, so use caution. Start with
low volume, then carefully increase to a comfortable level. Permanent
hearing loss may result from long-term exposure to sound at high volumes.
!
Build the circuit as shown. This project requires stereo
headphones or a stereo speaker (neither is included).
Turn off the left slide switch (S1), and turn on the right slide
switch. Press some of the keyboard keys and listen to the
echo. Set the 500k
W
adjustable resistor (RV3) for most
comfortable sound level (turn to the left for higher volume,
most of RV3’s range will be very low volume). Move the
lever on the adjustable resistor (RV) to change the amount
of echo (up is maximum echo, down is no echo). Try this
at different RV settings, because the effects are very
interesting with both high and low echo amounts. The
color LED (D8) will light when any green key is pressed,
but will not be very bright.
Now turn on the left slide switch to add the photoresistor
(RP) to the circuit. Wave your hand over the photoresistor
to change the sound. Try it with different levels of light
shining on the photoresistor, and at different RV settings.
Note that the “R” snap on the audio jack is not snapped
or connected, so there will not be any sound from the “R”
side of your headphones/speaker.
You can replace the 0.1
m
F capacitor (C2) with the 1
m
F
capacitor (C7) to lower the pitch of the green keys.
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