I made a little flying bug trap out of a box, a fan, and UV light strip. I decided to make it a 3D printed thing. I have them plugged into a cheap 3 port USB charger.

I used a centrifugal squirrel cage USB fan and a USB UV light strip. https://www.ebay.com/itm/264840828852 https://www.ebay.com/itm/323889059134?var=512919305048

I don't know if it works yet or is cost effective but it was fun to make.

The screen is just a 3D printed mesh and it seems to be a good size. I figure once a fly gets inside, it will be hard for them to get out with the airflow. Eventually, they should get blown into the holding area. I added a cone at the beginning in case a fly gets in the box and doesn't go to the holding area at least it will be hard for him to find his way out if the power goes off.

The door and the bottom lid snap in place so no screws are needed. I just superglued the fan to the box so no screws are needed for that either (but superglue is needed). The UV light strip I just sort of wound around inside. There's a finger that stands up so if you want to put one led pointing directly out, it can be stuck or glued there. I taped a little loop of paper over the front to make the UV beacon easier to see. The whole box actually glows which may or may not be good. It might be worth painting the outside with black spray paint if you think that's a problem. I think it looks neato so I don't mind. You may wish to put some glue or tape around where the wire opening is to keep any bugs from getting out there around the wires.

Anyway, if you print it, or mod it, or catch any bugs, please share! I'm curious to know your results good or bad if you tried it out.

I haven't tested it over time yet, so it may not work at all, so I'll try to add some results after I let it run a while.

I figure there's probably a better way to make it but I'm satisfied with this first initial iteration I think. Hopefully it works and is good enough.

Update: OK, well, it caught a few fruit flies but not many. I think the idea is solid to attract with uv light and then suck them in with a vacuum, but really this thing needs to be a lot bigger to do any good. wonk wonk.