This is the diagram of heat detector circuit which already integrated with siren circuit in the output. This circuit applies a complementary pair comprising NPN […]

Here the simple schematic of multitone siren alarm circuit. This multitone siren is effective for reverse horns, burlgar alarms, and many others. It generates five […]

This is definitely an ultra-sensitive fire sensor that exploits the direct piezoelectric property of an ordinary piezo component to recognize the fire. The lead zirconate […]

This is a very simple adjustable analog timer circuit diagram. You can build this circuit just for fun, for newbie project or may be…, this […]

This is the schematic diagram of LPG gas leakage sensor alarm. The circuit operates off a 9V PP3 battery. Zener diode ZD1 is applied to […]

Here the circuit diagram of electronic siren based NE555. This circuit produces a sound like factory siren. It applies a 555 timer IC which is […]

This is the circuit diagram of beeper sound. The circuit will generate the sound of a beeper which similar with the one in pagers. It […]

The following circuit is a simple, cheap and easy build motorcycle alarm. The circuit just required 2 transistors to drive the relay the the relay […]

This is a really simple sound effect generator based single sound generator chip UM3561. The UM3561 will generate four kinds of sound effects. The basic […]

Touch alarm circuit is widely used for security, which is installed on the door. The advantages of this alarm is because the cost is cheap […]