DIY from the archives: a humane bug zapper from 1971

Build an indoor insect trap from our August, 1971 issue, fully updated for today.

By Joel Barnard | Published May 28, 2009 12:25 AM EDT

On the left, a homemade bug zapper glowing in the dark, with the word "now" over it in red text. On the right, the August 1971 Popular Science article with the original plans for the zapper, with the word "then" over it in red text.

A little more modern than 1971.

Our third updated DIY project from the Popular Science digital archives involves luring and then trapping bugs that have managed to find their way inside your house—a truly universal problem. Follow along as we update a circa-1971 trap for today’s smarter, more intelligent insects for less than $20.

A bug trap you can make

An article about a DIY bug zapper, from the August 1971 issue of Popular Science magazine. — The inspiration: This vacuum-style bug zapper project’s design was first introduced in the August 1971 issue of Popular Science magazine. *Joel Barnard*

What you’ll need

A coffee can, a light bulb, wires, and other materials for building a DIY bug zapper from 1971. — Here’s what you’ll need. (Cheap and easy PopSci DIY projects with step-by-step instructions: Priceless.) *Joel Barnard*

The motor (pictured below) can be any small 10- to 20 watt, 120-volt AC motor that runs at 1,500 to 3,000 rpm. Old record players or small fans are a good source for these. If you can’t find anything lying around or at a thrift store, purchase a new small desk fan for around $10.

A small 120-volt AC motor on top of some black grid paper. — The motor. *Joel Barnard*

Instructions

1. Use the base of the coffee can to create the propeller. Make it 1 inch wide at its widest point and 3 inches long (assuming your coffee can is 4 inches in diameter).

A coffee can with a propeller drawn on the bottom. — Where the propeller will go. *Joel Barnard*

2. Attach the propeller to the shaft of the motor using glue, rubber bands, or, if it’s threaded, washers and a nut. In this example I was able to utilize part of the fan’s original plastic blades for a more precise fit. The less movement you have in the blades, the more efficiently (and quietly) they will move the air. Once secure, bend the fan blades so normal rotation of the motor causes downward air flow. The blades’ pitch should be 30 to 45 degrees.

A motor with a propeller on it, on top of black grid paper. — The motor and propeller together. *Joel Barnard*

3. Form the motor and lamp support bracket from perforated pipe-hanger iron. Lay out your fan and light bulb (in socket) as a measuring guide. The width of your bracket should be the same as the interior or your coffee can. Its height should allow for 1/2- to 1-inch clearance between the bulb and the fan blades.

A blue light bulb inside a bracket with a motor and a propeller under it. — The bracket, bulb, and motor. *Joel Barnard*

4. Attach bracket ends to the motor, using the screws holding it together.

A person attaching a metal bracket to a small motor with screws. — Close-up of the screw installation. *Joel Barnard*

5. Attach about a foot of lamp cord to the motor and tape up any exposed wires to prevent electrical shorts.

A motor and a bracket with an electrical power cord coming out of it. — The wires for the zapper. *Joel Barnard*

6. Tape the lamp cord halfway up on the inside of the bracket, and make sure it’s clear of the fan blades.

An electrical power cord taped to a metal bracket on top of black grid paper. — Cord: taped. *Joel Barnard*

7. Cut the cover from the bottom of a bleach jug that is slightly wider than your coffee can. The height of your cover should allow for the light bulb to be exposed 1 1/2 to 2 inches. Once your cover is cut, place the socket on top and mark where the bolt holes will need to be drilled.

A person using a small screwdriver to attach a light bulb socket to the top of a cut-off bleach jug. — Attaching the bulb socket to the jug. *Joel Barnard*

8. You will also need a hole in the center for a hook eye, and one for the outlet cord to enter.

An electrical power cord going into the bottom of a plastic jug. — The power cord. *Joel Barnard*

9. Attach both the motor wires and the outlet cord to the lamp socket.

A light bulb socket and a motor with a propeller inside a bracket on top of black grid paper. — Everything’s coming together. *Joel Barnard*

10. Install two 3/4-inch bolts and a hook eye through the top of the cover.

The bottom of a plastic jug with two bolts and a hook eye in it. — The hook eye and bolts in place. *Joel Barnard*

11. Line up the bracket and the socket over the bolts, then tighten them down with nuts.

A bracket and bulb socket inside half of a bleach jug. — The bulb socket and bracket going into the bleach jug. *Joel Barnard*

12. Screw in the bulb. Pretty straightforward.

A homemade bug zapper from 1971. — The bulb, bracket, and power cord are in now place. *Joel Barnard*

13. Slip the coffee can up over the motor and fan so that the blades are just below the surface. Use extra pipe-hanger iron to determine where holes should be drilled. Be sure not to place the screws where the fan blades will knock into them.

A person sliding a coffee can into a plastic jug over a bulb in a homemade bug zapper. — Positioning the coffee can. *Joel Barnard*

14. Check that everything is solidly tightened-down, and test the unit to make sure the fan blades spin clear of all screws, the cord, and the bracket.

A coffee can over a blue light bulb that's inside a plastic jug as part of a homemade bug zapper. — Testing, testing. *Joel Barnard*

15. For the bag, cut out an 18-inch-long section of undamaged pantyhose. Tie a knot in one end, turn the bag inside out and slip it over the end of the coffee can.