■ Make your very own laser burglar alarm
■ according to the image

■

Instrument:
1 photocell or LSR or LDR (as you call it) x1
2 5k variable resister x1
3 2n3904 transistor x1
4 1000uf 35v capacitor x3
5 speaker
6 9v battery x1
7 butt** cells x4
8 9v battery clip x1
9 most important of them all laser diode
10 vero board or circuit board