DIY a laser anti-theft system
1. First understand the circuit diagram
2. Solder the components according to the circuit diagram
A round row seat can be used at the triode and photoresistor to facilitate the replacement of components in the future.
3. Link the relay with Dupont wire and power on
4. As shown in the figure, the laser is aimed at the photoresistor, the relay light is on, and the normally open end is connected.
Remove the laser, the relay light is off, and the normally closed terminal is connected
A buzzer can be connected to the relay to form an alarm circuit