Elenco Projects 102-305 - Manual (Page 41)

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Project #217 Fading Siren
OBJECTIVE: To produce sound of
a siren driving away into the
distance.
OBJECTIVE: To produce
sound of a siren driving away
into the distance.
Replace the 470 μ F capacitor
(C5) with the 100 μ F capacitor
(C4), the siren fades faster.
Press the press switch (S2), the
alarm IC (U2) should make the sound
of an up-down siren that gets weaker
with time. The fading is produced by
the charging of the 470
μ F capacitor
(C5). After it is charged the current
stops and the sound is very weak.
To repeat this effect you must release
the press switch, remove the
capacitor, and discharge it by placing
it across the snaps on the bottom bar
marked A & B. Then, replace the
capacitor and press the switch again.
Project #218
Fast Fade
Siren
Project #216
OBJECTIVE: To control a motor using light.
Turn the slide switch (S1) on, the motor (M1) spins and the lamp (L2)
lights. As you move your hand over the photoresistor (RP), the motor
slows. Now place finger onto the photoresistor to block the light. The
motor slows down. In a few seconds, the motor speeds up again.
Motor & Lamp
by Sound
!
WARNING: Moving parts. Do not touch the fan or
motor during operation. Do not lean over the motor.