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Wireless alarm FM transmitter module – Circuit Schematic
Wireless alarm FM transmitter module
There are a lot of alarm systems on the market but you might be inclined to build your own. This little project can be put together using inexpensive parts read...
Circuit diagram for basic alarm with delayed trigger – Circuit Schematic
Circuit diagram for basic alarm with delayed trigger
The CD4001 quad 2-input NOR gate is a very versatile IC that can be used in an almost infinite variation. Here we will use it in the application of a simple ala...
Build an IR Beam Breaker – Circuit Schematic
Build an IR Beam Breaker
IR Beam Breaker Circuit Diagram. This is an Infrared beam breaking alarm ideal to use in entry or passages. It is based on the working of the popular IR sensor ...
Two-Zone Burglar Alarm – Circuit Schematic
Two-Zone Burglar Alarm
This is a two-zone alarm - with automatic exit, entry and siren cut-off timers. It can be triggered by the usual types of normally-closed input devices - such a...
garage door closing circuit – Circuit Schematic
garage door closing circuit
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Doorbell Warning Switch – Circuit Schematic
Doorbell Warning Switch
This circuit will light a lamp at a remote location when the doorbell switch is pressed. This circuit should only be used with the solenoid type doorbells, the ...
Smoke Alarm Circuit – Circuit Schematic
Smoke Alarm Circuit
The original smoke alarm circuit has some problems and has left some hobbyists and students disappointed. Rather than to attempt to solve its many problems, I h...
Refrigerator Alarm Circuit – Circuit Schematic
Refrigerator Alarm Circuit
When the light falls on the LDR, it becomes low ohmic. The voltage at the junction of LDR/R2 charges the C2 via the R1 slowly. After about 10 seconds, the capac...
High power siren circuit using CD40106 – Circuit Schematic
High power siren circuit using CD40106
This is a simple siren sound that high power output and very noisy. ICs, Digital ICs are easy to use number CD4046 Inverter circuit and four transistor power in...
Emergency Siren circuit Simulates Police – Circuit Schematic
Emergency Siren circuit Simulates Police
The heart of the circuit is the two transistor flasher with frequency modulation applied to the base of the first transistor. When the pushbutton is depressed, ...
12V/1.5A Residential AlarmCircuit – Circuit Schematic
12V/1.5A Residential AlarmCircuit
The following alarm circuit is designed with features which maybe suited for residential and commercial alarm system applications. It has 12V and 1. 5A regulate...
Laser Alarm fun stuff – Circuit Schematic
Laser Alarm fun stuff
So one day you wake up and you think why should I buy an alarm installation if I can just make my own. The normal answer is because you usually don`t have the s...
Detecting and locating RF bugs – Circuit Schematic
Detecting and locating RF bugs
We wrote about a phone bug in a previous post. Here`s an app note about a circuit for detecting and locating radio frequency transmitters. This design idea show...
Bugging Countermeasure – Circuit Schematic
Bugging Countermeasure
This allows a TSCM specialist the ability to "blink" a Spectronics bugging device on for a second or two to detect it, and then to shut it back down before the ...
Transmit output aid carrier alarm – Circuit Schematic
Transmit output aid carrier alarm
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Siren circuit – Circuit Schematic
Siren circuit
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Simple Small Portable Alarm Circuit – Circuit Schematic
Simple Small Portable Alarm Circuit
The system of using this circuit is positioning a little magnet close to the stalk switch SW1 while being connected to the hand or garments of the individual ho...
Simple Proximity Detector & Alarm Circuit – Circuit Schematic
Simple Proximity Detector & Alarm Circuit
This is a simple proximity switches with IC 4049th The IC4049 is a bipolar monolithic integrated circuit for use in metal-detection system / proximity sensing a...
Simple Light Sensor Alarm circuit with NE555 – Circuit Schematic
Simple Light Sensor Alarm circuit with NE555
This circuit sent out an alarm when its LDR sensor is exposed to light by sun or lamp. A 555 astable multivibrator was used here which sent signal a tone of abo...
How to Build Toxic Gas Detector and Alarm Circuit with TGS813 – Circuit Schematic
How to Build Toxic Gas Detector and Alarm Circuit with TGS813
The danger always exists, when the fuel gases such as propane or gas are confined to a small area. The alarm of toxic gases figs. 1-45 utilizes a tin-oxide-semi...