Mains Supply Failure Alarm
Whenever AC mains supply fails, this circuit alerts you by sounding an alarm. It also provides a backup light to help you find your way to the torch or the gene...
Latest British Police Car Siren circuit
The 555 on the right is wired as an alarm sound generator and the second 555 timer on the left is a 1 Hz astable multivibrator. The output of the left timer is ...
Photodiode Alarm
This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam o...
Alarm Digital Clock Schematic Diagram
after SCL is high at hand must be refusal chande voguish SDA line lone followed by the data is legally binding, the data loose change be supposed to be there ma...
british police car siren circuit
The 555 on the right is wired as an alarm sound generator and the second 555 timer on the left is a 1 Hz astable multivibrator. The output of the left timer is ...
Electronic Combination Lock
Electronic Combination Lock. This circuit is very basic to build. To open a the lock which is connected to the K1 Load you must press each momentary switch in t...
One-IC two-tones Siren
One-IC two-tones Siren. Double-tone Police sound. Single-tone old ambulance sound. Circuit diagram: Parts: R1,R3 470K 1/4W Resistors R2 680K 1/4W....
Siren Circuit
Siren Circuit. This circuit is to generate sound siren when S1 is pressed and increate sound frequency because charged C1, S1 is released when the frequency dec...
Doorbell for the Deaf
Doorbell for the Deaf. Circuit : Andy Collinson Email: [email protected] This circuit provides a delayed visual indication when a door bell switch is....
Assortment of Siren Circuits
Assortment of Siren Circuits. This month I am making 3 different types of siren circuits based on the 555 timer. The first circuit simulates the siren of a Br...
Motorcycle Alarm Number 4
Motorcycle Alarm Number 4. This is a simple - easy to build - transistor based motorcycle alarm. It`s designed to work at 12-volts. But - if you change the rela...
Rain Alarm
Rain Alarm. This circuit gives out an alarm when its sensor is wetted by water. A 555 astable multivibrator is used....
Fire Alarm Circuit using LDR (Light Depending Resistor)
Fire Alarm Circuit using LDR (Light Depending Resistor) as ablaze sensor. It warns the user adjoin blaze accidents. It relies on the smoke that is produced in t...
Simple Alarm Circuit Keeps Wandering Children
The receiver circuit in Figure 1 sounds an audio alarm when the transmitter (Figure 2) moves beyond a designated perimeter. The transmitter, a voltage-controlle...
Fire Alarm Circuit Using 555 IC
This is a design for fire alarm circuit. This circuit is based on a LDR and lamp pair for sensing the fire. The alarm will works by sensing the smoke produced d...
Door Knock Alarm Circuit
In the some building is need to using good security. For some example is using this design circuit. The door knock alarm is a simple design for the simple secur...
Car Speed Alarm Schematic
When we are driving sometimes we do not know the speed of our car, especially when we are in the course of the highway so nice and straight, if the cars speed i...
touch alarm system
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 and difficult to dete...
electronic combination lock LS7220
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 ...
Pyroelectric Fire Alarm System Diagram
Pyroelectric Fire Alarm System Diagram. The front end of the circuit contains a sensitive signal amplifier constructed close to IC1 (CA3130). It delivers a high...