This is a less cost and easy laser security system.
Step 1: Circuit Diagram
This is very easy laser security system.to built this we need ,
100ohms , 6.8k resisters
2n 7000 transistor
Step 2: Build the Circuit
Step 3: Place the Circuit
LDR is the main part of this circuit. Cover the LDR with the pen grip , because when other lights appear to the LDR it is not working good.When the switch on the LED is glowing and buzzer is working. When the laser's light appear to covered LDR the LED and buzzer is stop working. And something go through the laser's light the LED and the buzzer is working.