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Simple Alarm System – Circuit Schematic
Simple Alarm System
The circuit presented here is a very simple and yet highly effective alarm system for protecting an object. The circuit requires no special devices and can be b...
Simple 6-Input Alarm – Circuit Schematic
Simple 6-Input Alarm
This simple alarm circuit was designed for use in a combined garage and rumpus room. It can be assembled on Veroboard and uses just one IC plus a handful.....
Room Noise Detector Circuit Schematic – Circuit Schematic
Room Noise Detector Circuit Schematic
This circuit is intended to signal, through a flashing LED, the exceeding of a fixed threshold in room noise, chosen from three fixed levels, namely 50, 70 & 85...
Remote Alarm For Smoke Detector – Circuit Schematic
Remote Alarm For Smoke Detector
This alarm circuit was designed to monitor a mains-powered smoke detector located in a shed (which is used to house dog kennels). It provides complete iso.....
Pressure Sensor Alarm – Circuit Schematic
Pressure Sensor Alarm
General purpose circuit of the simple pressure sensor alarm is built around a couple of readily available cheap components. Working of this circuit is str.....
Powerful Security Siren – Circuit Schematic
Powerful Security Siren
Simple circuit No ICs required, 12V Battery operation This circuit was requested by several correspondents. Its purpose was to obtain more power than th.....
Park-Aid – Circuit Schematic
Park-Aid
This circuit was designed as an aid in parking the car near the garage wall when backing up. LED D7 illuminates when bumper-wall distance is about 20 cm. , D7+D...
Overheat Detector Alarm/Switch – Circuit Schematic
Overheat Detector Alarm/Switch
At the heart of this circuit is a precision integrated temperature sensor type LM35 (IC1), which provides an accurately linear and directly proportional o.....
Modulated Light Barrier – Circuit Schematic
Modulated Light Barrier
The light barrier described here can be used to guard an entrance. You can use it to signal of someone is walking through the corridor, or to check if the car h...
Modem Off Indicator – Circuit Schematic
Modem Off Indicator
The modem off indicator is intended especially for serious Internet surfers. It will be seen that the circuit of the indicator cannot be much simpler, or.....
mobile bug detector – Circuit Schematic
mobile bug detector
his handy, pocket-size mobile transmission detector can sense the presence of an activated mobile phone from a distance of one-and-a-half metres. So it ca.....
Midnight Security Light Circuit Schematic – Circuit Schematic
Midnight Security Light Circuit Schematic
Most thefts happen after midnight hours when people enter the second phase of sleep called ‘paradoxical sleep. Here is an energy-saving circuit that caus....
Mains Supply Failure Alarm – Circuit Schematic
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 th.....
Mains Failure Alarm – Circuit Schematic
Mains Failure Alarm
This circuit was designed to produce an audible alarm when the mains power is interrupted. Such an alarm is essential for anyone whose livelihood depends.....
Low Cost Burglar Alarm For Boats – Circuit Schematic
Low Cost Burglar Alarm For Boats
This low-cost burglar alarm employs a 12V strobe light and a truck reversing horn as the visible and audible alarm outputs while the alarm itself is a 12V.....
Laser-Guided Door Opener – Circuit Schematic
Laser-Guided Door Opener
This automatic door opener can be made using readily available components. The electromagnetic relay at the output of this gadget can be used to control t.....
Laser Alarm – Circuit Schematic
Laser Alarm
This circuit is a laser alarm system like the one we see in various movies. It uses a laser pointer beam to secure your valuables and property. Essentially, whe...
laptop protector – Circuit Schematic
laptop protector
Protect your valuable laptop against theft using this miniature alarm generator. Fixed in-side the laptop case, it will sound a loud alarm when someone tr.....
IR Beam Breaker – Circuit Schematic
IR Beam Breaker
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 Module TSOP 1738 which sense.....
Infrared Proximity Detector Alarm – Circuit Schematic
Infrared Proximity Detector Alarm
This circuit can be built from readily available low-cost components, some of which may even be hiding in your junkbox! The indicated value of 22 ? for re.....