DIY Lightning Detector

Lightning can be predicted by measuring a build up of static electricity in the air.

Famous American scientist Benjamin Franklin first invented a device that could warn of impending thunderstorms. Franklin's Bells converted static electrical energy in the atmosphere into mechanical energy, moving a bell clapper continuously between two oppositely charged bells. Using this scientific principle, it is a relatively straightforward task to construct your own version of Franklin's device with a few household materials and a few items of hardware.

Things You'll Need

• Wooden base, approximately 6 inches by 6 inches, 1 inch thick
• Wooden upright, approximately 12 inches by 3 inches by 1 inch
• Saw
• Screw
• 2 Bicycle bell tops
• 2 Emptied plastic pen barrels
• Large-headed tack
• Screw hook and eye
• Insulated wire
• Duct tape
• Screwdrivers
• Glue
• Hammer

Instructions

1. Cut the wood to size and drill a screw hole through the center of the wooden base. Drill a centered pilot at one end of the wooden upright, and proceed to screw the two pieces together. Make sure the screw does not protrude from the base so that the structure will remain level and stable.

2. Attach the bicycle bell tops onto two of the pen barrels with glue.

3. Drill two holes part-way through the wooden base. When locating these holes, bear in mind that when in place there should be a gap of about an inch between the bells. In turn, both the bells should be an equal distance from the wooden upright.

4. Attach the bells to the device by fitting their improvised pen-barrelled stands into the holes.

5. Push the large-headed tack through the plastic tip of the third pen barrel.

6. Twist a screw-eye into the opposite end of the barrel and hang it from a screw fitted in the wooden upright. This barrel has to hang down centrally, be able to swing freely within striking distance of each bell.

7. Attach a length of wire to the underside of one of the bells. Using duct tape, secure the other end of the wire to an indoor water pipe or a metal spike stuck into the earth outdoors, in order to ground the connection.

Tips & Warnings

• As a thunderstorm approaches, there is a build up of static electricity in the atmosphere. This static will collect on the ungrounded bell and charge it with electrons. The hanging tack-headed pen barrel is neutral and attracted to the charged bell. The tack-head hits the bell and is infused with the same charge, and is immediately repelled and pushed toward the grounded bell. When the improvised clapper then hits this bell, it loses its charge and will swing back and begin the whole process again. Continuous ringing will indicate that lightning is on its way.

• Do not use any other sort of external electrical supply in conjunction with this device.

References

• The World Around Us: Build aThunderstorm Predictor