Car Anti theft System Project using Microcontroller PIC16f73

Here is an outstanding one that is not only suitable for electronics engineering but mechanical engineering students too. This vehicle anti-theft system will lock the wheel when it rotates more than preset cycles whenever the key is in OFF condition. The main component of the circuit is PIC16F73; it’s compatible with PIC16F877A also but here we have used PIC16F73 as it’s comparatively small (28 pins). It uses an IR sensor system to detect the rotation of the wheel.

Circuit diagram of an anti-theft system for cars

Components Required

1. PIC 16F73
2. Transistor BC 548 X 2
3. Zener diode
4. Photodiode
5. IR Led
6. Capacitors (33pFx2;10uF)
7. Resistors (1k x5; 330 ohmX2)
8. Buzzer

Working

• An IR LED and photodiode pair are used to detect the rotation of the wheel. It’s attached to a disk that has openings; IR rays will pass through these openings.
• When the wheel is rotating, IR rays will be cut by the disk openings which will make a pulse output on the photodiode.
• The output of the photo diode is connected to the external clock input pin of TIMER0/COUNTER0 of the PIC.
• Pulses from the photodiode are counted by the counter. Each time the counter value is compared against the pre-set value and it will set the RC1 (1st pin PORTC).
• The relay used to control the locking device is connected at RC1. RC0 is used to check the key condition, locking is done only when the key is under OFF condition.
• The input from the key can be +12V, it is regulated by a 5.1V Zener diode connected in the circuit as PIC can’t connect +12V.
• RC2 is used to indicate that the system is working; here we connect a green LED which will start blinking when the system is ready.
• RC3 is used to connect an LED to indicate that the locking device is ON or OFF; it will set when locking occurs.
• RC4 is used to connect a buzzer to indicate that the preset rotation cycle has reached and the system is going to lock the wheel, it will be ON for 1 second and after that, it will reset.
• I have used the HITECH C compiler to compile the program. The crystal frequency used is 20 Mhz.

Conclusion

This project is simple and easy to fabricate, but capable of saving thousands of dollars for you. It can accurately detect any unusual activity and ensure anti-theft protection of your beloved car.