Elenco Projects 102-305 - Manual (Page 22)

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Project #145 Radio Music
Alarm
OBJECTIVE: To build a radio music alarm.
Project #147
Night Music
Radio
OBJECTIVE: To build a dark-
controlled radio transmitter.
Put the 100k Ω resistor back in as
before and instead connect the
photoresistor between X & Y (you
also need a 1-snap and a 2-snap
wire to do this). Now your radio
plays music when it is dark.
OBJECTIVE: To build a dark-
controlled radio transmitter.
Project #149
Radio Gun
Alarm
OBJECTIVE: To build a radio
alarm. OBJECTIVE: To build a light-
controlled radio transmitter.
Project #148
Night Gun
Radio
Replace the music IC (U1) with
the alarm IC (U2). Now your
radio plays the sound of a
machine gun when it is dark.
Remove the photoresistor (RP).
Now connect a jumper wire
between X & Y on the drawing.
If you remove the jumper now,
the machine gun sound will play
on the radio indicating your alarm
wire has been triggered.
Remove the jumper wire.
Replace the 100k
Ω resistor (R5)
with the photoresistor (RP). Now
your AM radio will play the
machine gun sound as long as
there is light in the room.
Project #150
Daylight Gun
Radio
OBJECTIVE: To build a light-
controlled radio transmitter.
Project #146
Daylight
Music Radio
Remove the jumper wire.
Replace the 100k
Ω resistor (R5)
with the photoresistor (RP). Now
your AM radio will play music as
long as there is light in the room.
You need an AM radio for this project. Build the
circuit on the left and turn on the slide switch
(S1). Place it next to your AM radio and tune the
radio frequency to where no other station is
transmitting. Then, tune the adjustable
capacitor (CV) until your music sounds best on
the radio. Now connect a jumper wire between
X and Y on the drawing, the music stops.
If you remove the jumper now, the music will
play indicating your alarm wire has been
triggered. You could use a longer wire and wrap
it around a bike, and use it as a burglar alarm!
To learn more about how circuits work, visit www.snapcircuits.net or page 74 to find out about our Student Guides.