STOP. This mosquito trap doesn't work well if at all. It was a fun project, and while I did manage to catch *one* mosquito in it in the couple weeks I ran it, it's far from being worth your time. I'm leaving this instructable up here so others can learn from my mistakes because, well, that's how science and engineering work.
Mosquito season is fast approaching - make a simple trap for cheap. The theory is that the light attracts mosquitos and the fan sucks them into the bag (usually shredding them in the process). This instructable is in experimental phase and will be updated as we go (see the Science step). I release it here as a neat community science project.I hope that folks will take the base idea, add a little twist, and then get back to me with the results. I will feature people's builds and improvements with full credit to the authors so other folks can learn from each other's mistakes and successes.
This build is darn simple on purpose. I get sick of instructables that require fancy tools like laser cutters, 3D printers, and CNC machines. I, myself, was tempted to make this super elegant with a CNC-cut or 3D printed box, but I didn't. Not everyone has the money for or access to fancy tools, and I wanted to respect that. Of course, you can fancify this to your heart's content, but you don't need to.
The only tool you need for this project is a soldering iron, and you can even get around that just twisting wires. A set of wire cutters is recommended as well, but you can accomplish the same thing with a pocket knife or a razor blade and a bit of caution.
Something I mention later but want to stress here as well: This trap will kill bugs (and possibly geckos) other than mosquitos. Think about adding a grating just large enough for mosquitos and ONLY turn this on when you are outside nearby. Use it like you might use a citronella candle: don't use it 24/7 when you don't need it.
I try to keep track of people's comments and respond to them. Before commenting on something, take a look at the "Science and Comment Feedback" step and see if I address your concern/idea ;)
Step 1: Materials
You will need a 12V power supply (you don't need anything fancy or high amperage), a standard computer fan with LEDS built in, a mesh bag with a 6 inch wide mouth (mine is a filter bag used in fish tanks), wire, superglue, and possibly magnets if you want to mount this to something steel. You will also need a long piece of scrap anything or a popsicle stick.
Solder and heat shrink are recommended, but not required (you can twist and tape around wires if needed, it's just not as sturdy).
Step 2: Superglue
Superglue (or hot glue...or epoxy...) your piece of scrap to the front of the fan on one of the corners. Superglue optional magnets to the other end. I actually added a second set so it would mount better to my airconditioner and not tip over.
Step 3: Solder
Cut two lengths of wire that are long enough to reach between the power outlet and where you plan to mount your trap and strip the ends. Lop the connectors off your 12V supply and your fan. Then solder the positive of your supply to one of the new wires and that wire to the positive of the fan. Do the same with the negative wires.
Note that red is positive and black is negative. There may also be a third wire on the fan that is usually yellow. You can snip that off and ignore it.
Tape or heat shrink the exposed wires. It is wise to add a bit of stress relief by making a small coil of wire and then fixing it to your mount with a zip tie, glue, or tape. This will keep your wires from getting pulled apart as easily.
Step 4: Fit the Bag
Simply slip the bag over the back side of the fan. You may decide to use rubber bands or tape to hold it in place.
Step 5: Mount and Enjoy!
Mount your new creation with magnets, tape, or a couple nails. Now, just plug it in and enjoy fewer biting bugs!
Step 6: Science and Comment Feedback
A few commenters are questioning whether or not mosquitos are attracted to light and whether or not this trap will work. Great question. Answer? I don't currently know, but I believe it will work. I based this idea around seeing many mosquitos hanging out on the screens of closed windows at night last summer. When it warms up here and the mosquitos are out, I will give this a more extensive try - if it doesn't work well, I will happily brand it as "Failed Quick and Dirty Mosquito Trap" so others may learn from my mistakes. I am a scientist and will turn on a dime if things don't meet a hypothesis.
A few people have suggested IR LEDs in place of the colored ones. As luck would have it, I do have a 12V IR spotlight we can try. My guess, however, is that it will do very little. IR LEDs emit a wavelength that is different than the ones things emit when hot. What would work better is to place a power resistor in front of the fan as a heating element. I will try both in a couple months and post the results :)
That said, you can turn this into a great science project and see what you can do with it. Do different colors attract more or different kinds of bugs? Does it work better if you mount it in a tube so the light only shows out one side? Will a slow stream of CO2 from a paint ball canister make it work better? How about if you stick a piece of worn, sweaty undies by the fan to see if body odor is an attractant? (Kinda gross, but hey, it's for SCIENCE!)
Try things, message me your results with pics, and I'll post them here with full credit to you and links to your Instructables profile.
On of the commentors sent me this: https://www.instructables.com/id/How-to-make-a-1-Mo...
It's a similar concept but with a large box fan. It would be kind of neat if folks combine his idea with mine and threw LEDs and/or a heat source to create a super mosquito trap. It would be interesting to see if it works better or worse :)
Step 7: Disclaimer and Front Grating
Other users brought it to my attention that this trap will kill harmless insects and possibly animals like geckos that are attracted by light.
This was not something I had thought about. Where I live in Colorado, the majority of flying insects that hover around lights are mosquitos and some moths (and we definitely don't have geckos).
It may be a very good idea to put a form of "reverse grating" over the front of the trap; something with holes large enough for mosquitos to pass through but small enough to stop larger insects and animals from getting hurt.
Also only turn this trap on when you are on the back porch and actually need it (treat it like a cintronella candle maybe). No sense shredding animals and bugs that can't hurt you while you are indoors.
jacob.cutter.10 made it!