DIY Security Alarms for a Garage

Place the motion detector face down on a work surface. Measure the length of the detector with a tape measure. Cut a 2-by-4 piece of wood to the length of the measurement with a hacksaw.

Hold the wood block vertically. Place the wood against the back of the garage on the wall slightly above chest level so that you can draw an imaginary line from the wood to the garage door. Screw the wood block into the wall with wood screws using a Phillips screwdriver.

Apply a line of bonding glue to the free side of the wooden block. Hold the motion detector with the sensor on the front facing you. Place the back of the detector against the wood block and hold it there for five minutes. Let the glue set for an additional six hours before continuing.

Plug the power cord from the motion detector into a wall outlet -- if the outlet is too far away, use an electrical extension cord to bridge the distance between the power cord and the outlet.

Rotate the sensitivity knob on the detector clockwise all the way. Rotate the volume knob on the detector likewise.

Stand to the side of the detector and turn it on. Take advantage of the 30-second delay built into the detector to exit the garage. Pull the garage door open from the outside to set off the alarm in the detector. Press the "Reset" button on the detector to reset the alarm and leave, closing the garage door.