1) Solder all the components on the circuit board and install the board in one of your project boxes. Solder them according to the schematic you see on the above right.
2) Drill holes in the other project box, one just a bit smaller than the photocell and one for the wires that go to the siren. Install the siren on the outside of the box. Install the backing on the project box with the siren. Glue some velcro to the outside of the box on the back of the box.
3) For the project box that holds the laser, drill two holes. Drill one for the switch, and the other for the laser. Mount the laser in the box with hot glue. Cut the end of the wire from the AC adapter, that is cut off the plastic adapter and run the wires into the project box and connect them to the wires for the laser. Install the switch in the wire so you can switch the laser on and off and secure the switch to the project box. Put a back on this project box and glue some velcro to the back of it.
4) Line up the laser with the photocell. Adjust the sensitivity using the variable resistor on the circuit board. Adjust it so the photocell operates only at night. Mount the laser box at about the level of your waist on the wall and in front of the door or window you wish to protect.
5) Turn the laser on, and get one of the small mirrors. Put handy tack on the back of the mirror and reflect the laser from this mirror to another mirror on another wall. Put another mirror where the laser is hitting the second wall. Continue to add mirrors for as many openings in your home you want to protect.
6) Mount the receiving end of the system that will trigger the siren. Make sure the laser lines up directly with the photocell.
7) If you want to test out the laser security system, just break the beam of the laser to the photocell and the siren should go off. If you have problems, make sure your circuit is exactly like described above.
This laser security system for your home may cost a maximum of twenty dollars.