Price: ₹700 - ₹499.00
(as of Nov 26, 2025 19:00:33 UTC – Details)
This simple door-opening alarm uses a hall sensor to produce sound when someone opens the door. The circuit can be installed at a workshop, office or home for security purposes. The 3-terminal hall sensor is easily available in the market. Hall sensor MH183 is a magnet-operated solid-state sensor. When the magnet is brought near the sensor, its output goes low. This low output is amplified by NPN transistor. NPN transistor inverts the operation. The magnet should be fitted on moving part of the door and the sensor at the door frame. When the door is closed, the magnet comes close to the sensor and the alarm is off. But when door is opened, the alarm makes a sound. The buzzer can be replaced with a 5V relay to control a mains alarm. When the door is closed, neither the buzzer sounds nor LED glows. But when the door is opened, the buzzer sounds and LED glows. ADDITIONAL INFORMATION – 1. Videos Tutorials (in Hindi) are available on YouTube (free of cost), No separate CD will be provided. 2. One complete DIY set, Including Relevant PCBs, Battery Cap, Passive Components, ICs, Sensors, Modules etc. 3. Full documentation, includes Circuit diagrams, Testing document, PCB Specifications, Reading Material etc. 4. Documentation will be provided on email 5. Power Source: We will not provide any Battery with all the kits as they are not allowed in the shipments by Air 6. How to make this DIY Kit, please see the video
DIY Kit – Door opening alarm (Hall Sensor)
This simple door-opening alarm uses a hall sensor to produce sound when someone opens the door.
The circuit can be installed at a workshop, office or home for security purposes