Alarm and Security Circuits
This section contains intruder alarms for your home, car and motorcycle, power failure and water level alarms and even a snore detector. All circuits are listed...
A Battery Powered Burglar Alarm With A Timed Siren Cut-Off
This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. It will accommodate the usual types of normally-closed input d...
Two Relay-Based Motorcycle Alarm Circuits
These are two - easy to build - relay-based alarms. You can use them to protect your motorcycle - but they have many more applications. If you use relays with 6...
6 Zone Alarm System
This alarm system has 6 independent zones, 1 timed entry/exit zone, a 7 segment LED display and a test or walkthrough facility. Suitable for a small office or h...
5 Zone Alarm System
This is a complete alarm system with 5 independent zones suitable for a small office or home environment. It uses just 3 CMOS IC`s and features a timed entry / ...
Simple Motorcycle AlarmCircuit by Ron J
The following schematic shows the Simple Motorcycle Alarm Circuit Diagram designed and drawn by Ron J. It uses micro-switches to protect removable panels and.....
Mini Voice Operated Relay
This is the circuit diagram of a voice operated relay. It similar with sound activation switch circuit which will turn on and turn off (connect and disconnect) ...
Security Light & Switch with PIR Sensor Update
This is a simple update to Mr. Hareendran s PIR Sensor Security Light circuit. It has a shortcoming limits the relay voltage to approximately 3.3V. While this m...
Electronic Doorbell Light Schematic
This 6V battery operated doorbell light circuit can be connected in parallel with any existing AC230V doorbell. When anyone push the doorbell switch, the bell s...
Economy radar detector
Economy radar detector Circuit diagram This circuit uses a 1458 dual op-amp to form a radar detector. C1 is the detector of the radar signal. The first op-amp f...
Car Park Aid Circuit
Park Aid Three LEDs signal bumper-barrier distance Infra-red operation, indoor use Circuit diagram: Parts: R1 10K 1/4W Resistor R2,R5,R6,R9 1K 1/4W Resistors R3...
Siren Driver circuit
Zetex Semiconductors have a siren driver IC Type ZSD100 available that is suitable for use in alarm systems for cars and model craft. With the addition of only ...
Wireless Car Alarm
This circuit is a wireless car alarm system that is built using two circuit modules, namely modules of transmitter and receiver modules. This circuit works on F...
Wailing Alarm Siren
Here the wailing alarm circuit diagram: Component parts List: R1,R5 4.7KR2 47KR3 10KR4 100KRx *see text C1,C4 100uF/25V, electrolyticC2,C3 0.01uF (10nF),.....
Vehicle Anti-Hijack Alarm No3
Vehicle Anti-Hijack Alarm No3 this circuit was designed primarily for the situation where a hijacker forces the driver from the vehicle. If a door is opened whi...
Two Simple Relay Based Motorcycle Alarms
Two Simple Relay Based Motorcycle Alarms Circuit These are two - easy to build - relay-based alarms. You can use them to protect your motorcycle - but they have...
Simple Electronic Combination Lock
The following diagram is a very easy and simple electronic combination lock based on IC LS7220. Component Part List: C1 = 1uF 25V C2 = 220uF 25V R1 = 2.2K Ohm Q...
Power Supply Failure Alarm
This is the special circuit design of power supply failure alarm. The vast majority of the power supply failure alarm / indicator circuits require a independent...
Multitone Siren Alarm
Here the simple schematic of multitone siren alarm circuit. This multitone siren is effective for reverse horns, burlgar alarms, and many others. It generates f...
Fire Alarm with LDR Sensor
This is the fire alarm circuit which use LDR to sense the smoke from the fire, so it can be used to detect any dark smoke. With the onset of summer season, poss...