Circuit diagram of miniature wireless alarm transmitter

Today I will share with you the circuit diagram of a miniature wireless alarm transmitter. The circuit of this alarm is simple. By changing the sensor at the transmitting end and setting the address code and status code of VD5026/5027, the uses of this alarm can be greatly expanded (such as multi-channel alarm, data transmission, etc.).

As shown in the figure below, a small magnet and a normally closed contact reed switch E form an intrusion detector. The small magnet is installed on the door leaf of the storage room. The reed switch E is close to the small magnet and installed on the opposite door frame. Normally, the door is closed. Since the small magnet is close to E, the two normally closed contacts inside E are disconnected by external magnetic force. The micro transmitter does not work due to no power supply. Once a theft occurs, the small magnet will move away from E with the door leaf, and E will lose the effect of the external magnetic field. Its two internal contacts will be closed by their own elasticity. When the micro transmitter is powered on, it will immediately send out a coded alarm signal.