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Project #43
Motor Magic
Project #44
Spin &
Shoot
Project #45
Spin Out
Siren
Project #46
Whirl Out
Warning
Project #47
Turn a
Tune
This project shows how a motor can be used to
convert mechanical energy to electrical energy and
sound. The speaker uses electromagnetism to
create changes in air pressure, which your ears feel
and interpret as sound. Think of the speaker as
creating pressure waves in the air just like waves in
a pool. You only see waves in the pool when you
disturb the water, so the speaker only makes sound
when the voltage changes.
This circuit is controlled by spinning the motor (M1) with your hands.
Turn on the switch. A police siren is heard and then stops. Spin the
motor and it will play again. Note, however, that music can be heard
faintly in the background of the siren.
Modify the last circuit by
connecting points X & Y with the
2.5V lamp (L1). The circuit
works the same way but now it
sounds like a machine gun.
Now remove the connection
between X & Y and then make a
connection between T & U with
the 2.5V lamp (L1). The circuit
works the same way but now it
sounds like a fire engine.
Now remove the connection
between T & U and then make a
connection between U & Z. The
circuit works the same way but
now it sounds like an
ambulance.
Now remove the connections
between U & Z and between V &
W, then make a connection
between T & U. The circuit
works the same way but now it
sounds like a familiar song but
with static.
CM-125_Manual_031514.qxp_CM-125_Manual_031514 4/2/14 12:19 PM Page 29
