Abstract :
Many visitors at tourist areas can enter without paying. Because of
careless guarding when the visitors were quiet and there is no crossbar at the
entrance of tourist areas. To help performance of officers not to be careless with
a tool to inform the arrival of vehicles that will enter the tourist areas.
Ultrasonic sensor function base that is as distance measurement. In those
ability to measure distance, it possible to use to measure velocity with two
ultrasonic sensor. Fisrt sensor records time and second sensor also records time
when detected object. It works when there is vehicle passing through the
ultrasonic range, the wave will touch the surface of the vehicle and reflect back
to the sensor.
When the measured speed is more 20 km/h, this condition is read as a
condition that there is a vehicle will enter the tourist areas, then this condition is
informed via telephone by GSM Module to the officer handphone at the entrance
tourist areas. After the information is received by the officer at the entrance to
the tourist areas, the officer will be prepared to guard the entrance when were
are vehicle that will enter the tourist area. Average error of measured speed is
3,5 %.