– 31 –
2. Receiver Circuit
IRR (light receiver unit) receives the infrared signal from the wireless remote controller. The receiver
amplifies and shapes the signal and outputs it.
3. Buzzer Circuit
When the buzzer sounds, an approx 3.9kHz
square signal is output from buzzer output pin
TT
TT
T
of the microcomputer. After the amplitude of this
signal has been set to 12Vp-p by IC711, it is
applied to the buzzer. The piezoelectric element in
the buzzer oscillates to generate the buzzer’s
sound.
Q141
L201
12V
IRR
VDD
Fig.2-1
Fig.3-1 Buzzer circuit
GND
V
OUT
C212
C211
R212
0V
0V
0V
R211
0V
ZD141
R141
R611
C611
0V
RECEIVER I/P
Microcomputer
13
BZ1
R721
12V
IC711
Microcomputer
Buzzer output
16130
BZ
Sound wave
Metal diaphragm
V
Pizoelectric element
V
Fig. 3-2 Buzzer Operation
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