In this video I am going to make my own "laser alarm. I do this with an LDR, BC547 transistor, buzzer, 2k ohm weather stand and a laser. As power supply I use a usb cable.

Supplies:
- LDR
- BC547 transistor
- buzzer 5v
- 2k ohm resistor
- laser
- Usb cable 2x

Schematic: https://robbemaaktdingen.blogspot.com/