Introduction: Laser Alarm

To make this simple alarm not even need more time. Yes we should have an NPN transistor that I have chosen them BC547, a rsistor100k and a consumable that you should inform you of any cases dagger .But I also used a plate with two transistors to pass on the issue of sound stood is you can even without the sign that can function.

Step 1:

  • Here you have been given schematic for a better information

  • Here's what else you need.

  1. transistor NPN
  2. resistor 100k
  3. buzzer,led etc
  4. pcb and bred board for testing