Elenco Electronics SNAP CIRCUITS SKILL BUILDER - Project 78 Reflection Detector; Reflection Detector Circuit; Project 79 Music Reflection Detector; Music Reflection Detector Circuit

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Music Reflection Detector
How good of a reector is a black piece of
paper? Tin foil? How about your hand?
Reflection Detector
Build the circuit to the left. Place it where there won’t be any room light
hitting the photoresistor (RP) (such as in a dark room or under a table),
and then turn it on. The 2.5V lamp (L1) will be bright, but there should
be no sound.
Take a small mirror and hold it over the lamp and photoresistor. You
should hear sound now. You have a reection detector! You can also
use a white piece of paper instead of a mirror, since white surfaces
reect light.
Build the circuit to the left. Place it where there won’t be any room light
hitting the photoresistor (RP) (such as in a dark room or under a table),
and then turn it on. The 2.5V lamp (L1) will be bright, and one song
may play, but then there should be no sound.
Take a small mirror and hold it over the lamp and photoresistor. You
should hear sound now. You have a music reection detector! You
can also use a white piece of paper instead of a mirror, since white
surfaces reect light.
Project 78
Project 79