USB Powered Bug Catcher

Inspired by, and designed for, the Printables Summer Camping Contest. The idea behind this device is to attract and capture any mosquitos or gnats that have gotten into your tent while you sleep because no one likes waking up covered in bites. The bug catcher can be powered by any portable 5V power supply that you would use for your phone.

The way it works is by attracting bugs to the UV LEDs at the top then sucking them down into the lower chamber using a small cooling fan. The bugs are then trapped in the bottom chamber with some sticky fly tape.

Main Post: Printables

Electronic Components/Hardware (I'm providing some links but these are all standard parts so feel free to source them from anywhere):

1. 5V Mini Fan (comes with some M2.5 pan head fasteners and nuts that are used in the hinge)
2. UV Purple 3mm LEDs
3. USB C Female Chassis Power Cable
4. 220Ω Resistor (the value can vary, this is just for the LEDs)
5. M3x4 Heat Set Inserts
6. M3x5 SHCS
7. M3x14 SHCS

Printed Parts (part stl files): Printables

The circuit for this project is straightforward with the fan and LEDs all in parallel. The trickiest part is soldering up the LEDs on the perf/prototype board to fit in the top section of the bug catcher. If this project gets enough interest I might design a simple open source PCB to make life easier, so let me know if that's something people would be interested in.

If you're using a perf/prototype board like I am then I'd recommend the following LED arrangement (ignore the orientation of GND here, this is just to show the location). Ultimately the number and placement of the LEDs is not overly critical, they just need to be able to fit in the mount opening.

First thing that needs to be done once all of the parts have been printed is to press in the heat set inserts into the LED mount and main body.

For the LED mount only 3 of the legs get the insert, the other leg is hollow to allow for the power cables for the LEDs. This is then secured to the fan cover with the shorter M3 Fasteners.

The main body gets 4 inserts in the holes surrounding the tapered funnel. At this point we can also press in the USB C female chassis as shown.

Secure the LED circuit to the mount with some hot glue or other adhesive (verify that the top cap can sit flush with the body prior to gluing). Then secure to the fan cover using the shorter M3 fasteners as shown below. There are three holes on the underside that are counterbored to fit the socket head. The remaining hole is for the circuit power cables.

This is where things start to get a bit tight. The power and GND cables are soldered together then wrapped around the outside area of the fan. The upper assembly is then secured with the longer M3 fasteners through the mounting holes in the fan into the heat set inserts. The top cap can then be secured in place with hot glue or other adhesive.

The bottom cap hinge utilizes the M2.5 pan head screw and nut that comes with the fan (if your fan didn't come with this hardware you'll need to order some). Note that in some of the images above the bottom cap is already installed; the order of operations here for the assembly is not critical.

The final step of the assembly is to add some mesh. To print the mesh be sure to turn off top and bottom layers and use an infill of 60% to create the mesh you see below.

You can also use screen mesh or any fabric mesh that is small enough to prevent the bugs from escaping will work. Just cut to size and insert into the bottom section of the main body and secure with some glue.

Once the bug catcher is fully assembled, some sticky fly paper or tape can be placed in the bottom cap to trap the bugs for good. I also tested this by placing the device next to some fruit in the kitchen to get rid of some fruit flies (so bonus this works great inside a house and inside a tent).

Add a carabiner or hook to carry around and hang the bug catcher in your tent or wherever you'd like it. It's small and light which makes it a perfect fit for camping.