CAR SECURITY SYSTEM WITH REMOTE CONTROL SIMPLE ELECTRONIC PROJECTS

Here is an inexpensive electronic car security system with remote control that uses readily available, low-cost components. The gadget comprises a base unit, which remains fitted inside the vehicle, and a remote control handset for activating/deactivating the base unit. The base unit, in enabled state, can be used to set off an alarm device when an unauthorised person tries to gain access to the vehicle.

Remote control handset

The remote control handset is used to switch on/off the base unit installed inside the vehicle.

Base Unit

RAIN ALARM SIMPLE ELECTRONIC PROJECT

Schematic diagram for rain alarm.

GIVES BEEP WHEN WATER IS IN CONTACT WITH THE WIRE

Water is a conductor of electricity. When water is in contact with the probe then there is a flow of current which reaches to the base of Q1. Transistor Q1 is a NPN transistor which conducts. With the conduction of Q1 electron reaches to Q2 which s a PNP transistor .

Q2 also conducts and current flows through the speaker. In aspeaker there is inductive coil which causes motion in one direction and also produce induce current which is in opposite direction to the flow of current this induce current in the form of pulse flows through a capacitor, resistance and switches off Q1 and relax .

This process repeats again and again till probe is in contact with water or we can say there is a oscillation in the circuit thus speaker diaphragm vibrates and gives a tone. Frequency of the circuit depends on the value of Speaker Coil impendance, Capacitor and Resistance Value.