Elenco Electronics 202 - Manual (Page 23)

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Project #15
OBJECTIVE: To show how an integrated circuit can be used as
a musical doorbell.
Build the circuit shown on the left. When you turn on the slide switch
(S1), the music integrated circuit (U1) may start playing one song then
stop. Each time you press the press switch “doorbell button” (S2) the
song will play again and stop. Even if you let go of the press switch,
the integrated circuit keeps the song playing until it has reached the
end of the song.
Musical integrated circuits are used to entertain young children in
many of the toys and chairs made to hold infants. If the music is
replaced with words, the child can also learn while they are
entertained. Because of great advances in miniaturization, many
songs are stored in a circuit no bigger than a pinhead.
Musical Doorbell
Project #16
OBJECTIVE: To show how integrated circuits can also create
loud alarm sounds in case of emergencies.
Modify the circuit used in project #15 to look like the one shown on the
left.
When you turn on the slide switch (S1), the music integrated circuit
(U1) may start playing one song then stop. The song will be much
louder than in the previous project because it is now being used as an
alarm. Each time you press the press switch “alarm button” (S2) after
the song stops playing, the song will play again, but only while you
hold the button down.
Momentary Alarm