Earthquake alarm circuit schematic

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...

Key Code Combination High Security Door Lock

This project involves an electronic lock that supports numerous combinations, which can be easily modified. It unlocks only with the correct sequence of four consecutive numbers. A significant feature of this electronic lock is that the four numbers must be...

Alarm Power Supply

This power supply is suitable for a modular burglar alarm but can also serve other applications. It is designed to provide a 12-volt output with a current capacity of up to 1 amp. In case of mains failure, the backup...

House Alarm Loop Circuit

This circuit features open and closed loop contacts (switches 1, 2, 3) that activate the alarm, which remains on for a duration of 5 to 10 minutes. The triggering delay for entrance and exit is set to 27 seconds. Additionally,...

Menci alarm produced schematic circuit diagram

The alarm circuit operates as follows: When the power switch SW1 is turned on, the alarm system becomes active. If a magnet is brought close to the spring, the magnetic field attracts the spring, causing the dynamic and static switch...

Personal Alarm

This circuit, enclosed in a small plastic box, can be placed into a bag or handbag. A small magnet is placed close to the reed switch and connected to the hand or the clothes of the person carrying the bag...

Car Speed limit Alarm

This circuit has been designed to alert the vehicle driver that he has reached the maximum fixed speed limit (i.e. in a motorway). It eliminates the necessity of looking at the tachometer and to be distracted from driving. There is...

Simple Alarm circuit

A simple alarm circuit with a diagram and schematic that generates a multi-tone sound. This alarm circuit is suitable for use in burglar alarms and sirens and is designed using dual op-amps MC1458 and LM380. The described alarm circuit utilizes dual...

Pots water alarm circuit

The flowers in pots require watering, as relying solely on the observation of moist soil surfaces can be unreliable. To address this issue, a flower watering indicator has been developed. This circuit includes a field effect transistor (VT1), a second...