23-05-2012, 04:12 PM
Speed Checker for Highways
[attachment=22917]
While driving on highways,
motorists should not exceed
the maximum speed limit
permitted for their vehicle. However,
accidents keep occurring due to speed
violations since the drivers tend to ignore
their speedometers.
This speed checker will come handy
for the highway traffic police as it
will not only provide a digital display
in accordance with a vehicle’s speed
but also sound an alarm if the vehicle
exceeds the permissible speed for the
highway.
The system basically comprises
two laser transmitter-LDR
sensor pairs, which are installed
on the highway 100 metres apart,
with the transmitter and the
LDR sensor of each pair on the
opposite sides of the road.
Circuit description
the circuit of the speed
checker. It has been designed assuming
that the maximum permissible speed
for highways is either 40 kmph or 60
kmph as per the traffic rule.
The circuit is built around five
NE555 timer ICs (IC1 through IC5),
four CD4026 counter ICs (IC6 through
IC9) and four 7-segment displays (DIS1
through DIS4).
Construction and working
Assemble the circuit on a PCB. An actual-
size, single-side PCB layout for the
speed checker is shown in Fig. 4 and its
component layout in Fig. 5.
Before operation, using a multimeter
check whether the power supply
output is correct. If yes, apply power
supply to the circuit by flipping switch
S3 to ‘on.’ In the circuit, use long wires
for connecting the two LDRs, so that
you can take them out of the PCB and
install on one side of the highway,
100 metres apart.
[attachment=22917]
While driving on highways,
motorists should not exceed
the maximum speed limit
permitted for their vehicle. However,
accidents keep occurring due to speed
violations since the drivers tend to ignore
their speedometers.
This speed checker will come handy
for the highway traffic police as it
will not only provide a digital display
in accordance with a vehicle’s speed
but also sound an alarm if the vehicle
exceeds the permissible speed for the
highway.
The system basically comprises
two laser transmitter-LDR
sensor pairs, which are installed
on the highway 100 metres apart,
with the transmitter and the
LDR sensor of each pair on the
opposite sides of the road.
Circuit description
the circuit of the speed
checker. It has been designed assuming
that the maximum permissible speed
for highways is either 40 kmph or 60
kmph as per the traffic rule.
The circuit is built around five
NE555 timer ICs (IC1 through IC5),
four CD4026 counter ICs (IC6 through
IC9) and four 7-segment displays (DIS1
through DIS4).
Construction and working
Assemble the circuit on a PCB. An actual-
size, single-side PCB layout for the
speed checker is shown in Fig. 4 and its
component layout in Fig. 5.
Before operation, using a multimeter
check whether the power supply
output is correct. If yes, apply power
supply to the circuit by flipping switch
S3 to ‘on.’ In the circuit, use long wires
for connecting the two LDRs, so that
you can take them out of the PCB and
install on one side of the highway,
100 metres apart.