Project #19
Magical Music
Project #20
Press & Play
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.
Having no resistor in series with the speaker
allows more current to flow through the speaker
producing a louder sound.
-20-
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
(S2), the integrated circuit keeps the song playing until it has reached
the end of the song.
Modify the circuit used in Project #19 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.
CM-125_Manual_031514.qxp_CM-125_Manual_031514 4/2/14 12:19 PM Page 21
