Rangkaian sensor parkir

Rangkaian Sensor Parkir
Mobil
Rangkaian ini dapat mendeteksi jarak
antara bemper mobil dengan dinding
atau apa saja yang menghalangi
kendaraan baik yang berada di depannya
maupun dibelakang mobil. Jarak bisa
diketahui dari kombinasi antara LED D5
dan D7. Misal bemper berada pada jarak
25cm atau kurang maka D7 akan
menyala, jarak berada pada 20cm maka
D7dan D6 akan menyala, dan jarak pada
5cm makanD7, D6, dan D5 akan menyala
semua. Pada jarak kurang dari 25cm tidak
ada Lampu Led yang menyala, ini
mengindikasikan masih pada jarak aman
atau masih jauh dengan benda atau
rintangan yang menghalanginya.
Rangkaian sensor parkir mobil ini memiliki
2 buah rangkaian yakni rangkaian
receiver dan transmitter. Dan sebagai
sensornya digunakan LED Impra Merah
dalam hal ini D1 pada transmitter dan D2
pada receiver.
Note:
D1 & D2 must be
mounted close (~2cm)
D1 can be a general
purpose IR LED.
D2 can be general
purpose IR photo diode
with sun filter.
Transmitter as well as
receiver can be powered
from the car battery.
For proper working of
the circuit, some trial
and error is needed with
the position of D1 and
D2 on the dash board.
Two ICs are used in the circuit. The IC1
(NE555) is wired as an astable
multivibrator for driving the IR Diode D1
to emit IR pulses. The operating
frequency of the transmitter is set to be
120Hz.The IR pulses transmitted by D1
will be reflected by the obstacle and
received by the D2 (IR photo diode).The
received signal will be amplified by
IC2a.The peak of the amplified signal will
be detected by the diode D4 and
capacitor C4.R5 and R6 compensates the
forward voltage drop of D4.The output
voltage of the peak detector will be
proportional to the distance between
car’s bumper and obstacle. The output of
peak detector is given to the inputs of
the other three comparators IC2b,IC2c
and IC2d inside the IC2(LM324).The
comparators switch the status LEDs
according to the input voltage their
inverting inputs and reference voltages at
their non inverting inputs. Resistances
R7 to R10 are used to set the reference
voltages for the comparators.
Lay out IC LM324
Features
Internally frequency compensated for
unity gain
Large DC voltage gain 100 dB
Wide bandwidth (unity gain) 1 MHz
(temperature compensated)
Wide power supply range:Single supply
3V to 32V or dual supplies ±1.5V to ±16V
Very low supply current drain (700 μA)—
essentially
independent of supply voltage
Low input biasing current 45 nA
(temperature compensated)
Low input offset voltage 2 mV and offset
current: 5 nA
Input common-mode voltage range
includes ground
Differential input voltage range equal to
the power supply voltage
Large output voltage swing 0V to V+ −
1.5V.