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Laser diode emits a intense beam of visible red light. This module can be used with photo resister module/light dependent resistor(LDR) to remote or receive signals.
In this exercise, the alarm will turn on when detect the object between the laser diode and the LDR. Low power laser device will use, and connect touch switch to turn off the alarm from the buzzer and to reset the whole program.
Do not point the laser to eyes!