Abstract:
The project is to design an intelligent traffic monitoring system that takes decision according to the flow of traffic on each road. Inductive loop sensors have been designed and implemented to detect the vehicles on the road. The sensor works on the principle of magnetic field induction. A round wire (AWG# 22, 1.2mm diameter) is used to form a number of loops (turns) which is placed in the road at a depth 2 to 5 cm. A 100 kHz, 10V p-to-p signal is applied to the loop wire. When vehicle passes over the loop wire it induces eddy currents in the metal parts of the vehicle which decreases the voltage of signal. This decrease in voltage is detected by the electronic part of the sensor. The electronic unit comprises of a rectifier and a comparator. Rectifier converts AC signal coming from loop, into the DC voltage and comparator is used to give a positive pulse if vehicle passes over the loop.
Algorithm is implemented in PLC. Once the algorithm is started the signal for one road is green for fixed time. In the mean while when signal for one road is green the counters for other roads are ON and continuously count vehicles for their respective roads. When green signal of road turns to yellow then the number of vehicles counted by the counter of next road, till now, is given to timer of road A for green signal. In this way the algorithm works. Ladder Diagram programming is used to implement the algorithm in PLC. Any vehicle trying to cross the red signal is detected by the system and a picture of the vehicle can be taken by a camera for further actions.
