Most commercial fire alarms are actually smoke detectors. These employ reasonably sophisticated technology to pick up carcinogens in the air. A straight-up fire alarm is much simpler, however, because it doesn't need to detect smoke. It only needs to detect heat. With that in mind, you can make your own fire alarm using only an inexpensive buzzer and some common household items
Things You'll Need
- 1 9v Battery and clip
- 1 Buzzer or alarm
- 1 Piece of craftsman's wax
- 2 Lengths of electrical wiring
- 2 Pieces of aluminum
- 1 Spring-loaded clothespin or wooden alligator clip
- 1 Piece of plywood
Use a length of electrical wire to connect the positive (+) terminal from a 9v battery clip to the corresponding terminal in a compatible buzzer or alarm. The alarm should have a screw that you can slip the wire through. Tighten this with a screwdriver. Some may have positive and negative wires of their own. If it does, you can simply twist the positive wire from the buzzer together with the positive wire from the battery clip. Do not place the battery in the clip yet.
Wrap a second length of wire around one jaw of a spring-loaded clothes line or wooden alligator clip. Connect the free end of the wire to the remaining terminal on the buzzer. Do this either by twisting it around the end of the wire or tightening the screw to ensure that the wire is secure.
Wrap the remaining wire from the battery clip around the second jaw of the alligator clip.
Wrap two pieces of aluminum foil around the two jaws of the alligator clip. This should cover the wires. The foils should come into contact when the jaws are closed.
Wedge a piece of craftsman's wax in between the jaws of the clip, making sure it separates the two pieces of foil.
Connect the alligator clip, battery clip and buzzer to a thin piece of plywood using glue. That will allow you to move the alarm around easily.
Attach the battery to the clip. Place the alarm near your bed or similar area you want to monitor for heat. Any nearby fire will melt the wax, completing the circuit on the wires and setting off the alarm.
Tips & Warnings
- Check the melting point on the wax when you buy it. Generally speaking, you want wax that will melt at a temperature of 120 to 140 degrees Fahrenheit: warmer than the hottest day. Yet, you don't want it so warm that the alarm won't trigger when a fire breaks out.
- Check the battery regularly if you want to alarm to stay effective. It won't run without adequate power.
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