Elenco Electronics 202 - Manual (Page 63)

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Project #128 Radio Music
Alarm
OBJECTIVE: To build a radio music alarm.
Project #130
Night Music
Radio
OBJECTIVE: To build a dark-
controlled radio transmitter.
Put the 100k Ω resistor (R5) back
in as before and instead connect
the photoresistor (RP) 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 #132
Radio Gun
Alarm
OBJECTIVE: To build a radio
alarm. OBJECTIVE: To build a light-
controlled radio transmitter.
Project #131
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 4-snap wire
between X & Y on the drawing.
If you remove the 4-snap wire
now, the machine gun sound will
play on the radio indicating your
alarm wire has been triggered.
Remove the 4-snap 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 #133
Daylight Gun
Radio
OBJECTIVE: To build a light-
controlled radio transmitter.
Project #129
Daylight
Music Radio
Remove the 4-snap 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 variable capacitor
(CV) until your music sounds best on the radio.
Now connect a 4-snap wire between X & Y on
the drawing, the music stops.
If you remove the 4-snap wire now, the music
will play indicating your alarm wire has been
triggered. You could use a long wire instead of
the 4-snap and wrap it around a bike, and use it
as a burglar alarm!