Cut Phone Line Detectors
#phone line
#detector
#security
#surveillance
#circuit
#alarm
#monitoring
#telecommunication
#sensor
#home automation
No description available.
Surveillance Transmitter Detector
The site features several low-power transmitters, but until now, there has been no receiver. This circuit can be utilized to scan an area or room, indicating whether a surveillance device is active. The challenge in creating an effective detector lies...
Power disconnection alarm circuit diagram
The circuit operation principle of the device illustrated in Figure 13 is as follows: When the barbed wire (Fe) remains intact, the output pin (O) of the LSE is at a high state. Consequently, the transistor (VT) remains off, and...
Phone line indicator using BF256B
With this circuit can determine whether any of the phones of the same line is busy (it's up the handset), with the help of a LED. The circuit has no measurable effect on the telephone, so that there are problems...
Two HiJack Alarms
The first circuit was designed for the situation where a hijacker forces the driver from the vehicle. If a door is opened while the ignition is switched on - the circuit will trip. After a few minutes delay - when...
Single Zone Alarm
A single zone alarm circuit with entry and exit delay and other facilities. The circuit features automatic exit and entry delays, timed bell cut-off and system reset. It has provision for normally open and normally closed switches and will suit...
Locker Guard Locker Security Alarm Circuit Anti Theft
Locker Guard Circuit Diagram. This compact circuit is designed to protect a locker or almirah from burglary. If the locker is opened while in the armed state, the circuit triggers a loud police siren to deter the burglary attempt.
The Locker...
Mini Alarms
This is a selection of small self-contained alarm circuits. They have a very low standby current; and are suitable for battery operation.
The described alarm circuits are compact and designed for low power consumption, making them ideal for battery-powered applications. These...
Single Alarm Circuit
This is a single alarm circuit. The circuit includes automatic exit and entry delays, a timed bell cut-off, and a system reset. It has provisions for normally open and normally closed inputs.
The single alarm circuit is designed to provide security...
Automatic Turn-Off Alarm With Delay
In this circuit, IC1A and IC1B serve as a monostable multivibrator. Any input from the sensors SI through S5 triggers IC1A to produce a logic low signal, which activates IC1B, turning on Q1 until the capacitor C3 discharges through resistor...