LIFE FOR FLIES JUST GOT MORE DANGEROUS.
This is a Special Weapons And Tactics device designed to eliminate insects with clinical precision.
100% accuracy due to precision laser targeting.
100% kill or stun due to overwhelming kinetic energy pulse.
THIS IS NOT A TOY (But it's damn good fun.)

Step 1: Tools and Materials

To make the SWAT Flykiller, you will need :-
A long, thin piece of wood - I used a piece 3 foot by 3/4" x 1/2" (900mm x 10mm x 12mm). Size not critical, but it needs to be light and not too flexible.
A length of 2.5 or 3mm elastic shock cord. This is the thin elastic which runs through the middle of long fibreglass tent poles. You can get it from eBay or any camping shop. Mine was a 2 foot piece which came in the 'repair kit' for our tent.
A pocket laser pointer - any colour you like.
A short length of plastic tube to hold the laser pointer. Mine slides sweetly into a piece of 5/8" (15mm) tube from the DIY store.
One strong clothes peg (clothes pin) for the trigger.
A few small screws and a short piece of thicker wood for the handle.

Required tools are a hot-glue gun, cyanoacrylate (10 second) glue, saw, small file, screwdriver.

Step 2: Trigger, Handle and Laser Mount

Cut the end of the wooden strip (barrel) so it's slightly sloping (pic 1), and file a rounded notch in the end (pic 2). The side with the notch is the top of the gun.

Use a small file to roughen up the jaws of the clothes peg and file away the front edge to increase the angle so it will grab the cord better (pic 3). Hot-glue the peg to the wood on top and at the other end to the notch.

Cut a piece of the plastic tube 3 1/2 inches long and hot-glue it to the bottom of the barrel 1 1/2" back from the sloping end (pic 4). It must be exactly in line with the barrel.

Hot-glue the handle to the underside of the barrel, 15" back from the notch end (pic 5).

The SWAT Flykiller should now look like pic 6, and sliding the laser pointer into the tube should press the stud and turn it on.

Step 3: Attaching the Elastic

The elastic needs to be prepared by slightly flaring one end and dribbling superglue in to a length of half an inch or so (pic 1). This will stop it fraying, make it easier for the trigger to grab and have more impact when it hits.

Make up a clip from a piece of scrap plastic and 2 screws to fit to the barrel, just in front of the laser tube (pic 2). Clamp the elastic in the clip so there's 17" loose to the prepared end. Don't cut the excess off, but take it around another screw and lightly glue it to the barrel out of the way (pic 3).

Step 4: Testing and Calibration

Slide the laser pointer into the tube and the operating stud should be pressed down, turning the laser on. Insert it so the stud is pointing either directly up or down. Take the elastic up through the notch, and grab it in the jaws of the clothes peg. If the elestic slips out of the peg, beef up the spring with an elastic band around it (pic 2). The weapon is now ready for testing . . .

Find a piece of flat polystyrene foam and make several small splodges on it with a marker pen. From a distance of around two feet, centre the laser dot on the splodge and fire by gently pressing the end of the peg. The elastic will hit with a satisfying 'THWACK' and you should see a dent in the polystyrene, or possibly the elastic will embed itself.

If the elastic consistently hits either left or right of the spot, you've probably not been careful enough gluing on the laser tube. If the elastic hits high or low, turn the pointer over so the stud is the other way up. If that's no better, you may have to unstick and re-glue the tube with a slight slant to it. (Mine was dead on first time.)

Once you can consistently hit the splodges dead-centre, it's time to go hunting . . .

Step 5: Notes

I was recently camping with the family and after a tent-pole failure, discovered the spare shock cord elastic in the repair kit. I spent an enjoyable afternoon twanging and tormenting the kids with the Elastic of Doom {evil grin}.
Once back at home, I found the elastic still in my pocket, and as we had a few annoying flies buzzing around, found you could twang them quite effectively (but not too accurately) with the elastic. Later that evening I saw my laser pointer sitting on a shelf and the idea was born . . .

I did wonder if this could be developed into a commercial product but found that someone has patented a device which uses the same elastic method to kill flies (but doesn't have my innovation of the laser targeting).

The elastic lasts about 100 twangs. You need to cut it back by a couple of inches, then loosen and pull more through the clamp.

Flies seem totally oblivious to red or green laser light shining on them.

I was going to do more pics and a video of this in action but I dropped my laser pointer on a concrete floor and broke it. New laser time, methinks.