Door opening alarm using hall sensor circuit. The circuit diagram of the door opening alarm is shown in Fig. 1. It is built around hall sensor MH183 (IC1), pnp transistor BC557 (T1), npn transistor ...

Assemble the circuit on a general-purpose PCB and enclose in a suitable case. Fix the Hall sensor at the corner of door frame and the magnet on the door, keeping its north pole (N) oriented towards ...

IR sensor Module. Components. IR pair (IR LED and Photodiode) IC LM358; Resistor 100, 10k, 330 ohm; Variable resistor – 10k; LED; You can see the connections in the IR sensor circuit diagram. Photo ...