DIY All in One Flying Critter Catcher and Humidifier/Air Freshener

Picture this: you're staying on a friend's farm for a few weeks doing some work for him, but the flies in your room just won't leave you alone. You lie there, staring at the ceiling, and you count over 13 flies! And then you discover that there are even more on the walls! And when there aren't any flies, there are 50 moths...

Well, this is my story right now.

As I was thinking for days of a good product idea to make with my new 3d-Printer, it hit me like a ton of bricks (or a ton of flies diving into my ears). I should make a fly catcher!

Well, since there are plenty of fly traps and pest-control methods out there, I wondered, "how can I make a more effective method of not only getting rid of flies, but also freshening up a room?"

After smacking about 11 flies with a fork (yes, I really spent half an hour doing that don't judge me), I decided that this fly catcher needs to be hassle-free, low maintenance, and easy to clean so you don't ever have to deal with cleaning fly guts off a window again :D

Justification:

Why not just use a regular fly zapper?

Your average fly zapper will need bulb replacements every few months to maybe a year depending on your usage. And cleaning them can be a huge pain- especially for those bugs that get extra sticky! Not to mention their power consumption- anywhere between 15-85 watts when averaging out online accounts- which really isn't too bad, but we can do better. And lastly, aesthetically they are just highly inconvenient for indoors in a household, a small apartment, and especially dorms. And by inconvenient I mean ugly.

Why not just use a DIY solution using a plastic bottle?

If you search online for a DIY and cheap solution to the expensive fly zapper problem, you will find many people who have made one with a plastic soda bottle by inverting the lid-side down. The trick is to use an ultra-pungent bait to lure the flies into the bottle where they proceed to drown. I have heard of people doing this with meat, fish, and even vinegar. The problem once again, is that it is incredibly unaesthetic to have a 1 cm thick layer of dead flies floating dead in a yellowed soda bottle. Not to mention the pungent smell, wasting of kitchen goods every refill, and the risk of spilling a pool of wet and dead flies everywhere!

So, the birth of this flying critter catcher resulted! It lures flying insects using blue and/or UV LEDs, sucks them in with a fan, and freshens the air using a humidifier with some scents added!

I pulled the prices off Amazon listings just for a general reference.

1. Access to a 3D printer. Or you can use an online 3D printing service. You can make these parts using wood or cardboard if you want, but 3d printing is the easiest.
2. 120mm PC fan x1 ($5-10). Look for a high static pressure fan if you can as they will have better suction.
3. 12V Blue and/or UV LED strip. x1 ($7-14). I got mine for about $2 at a local China shop.
4. Humidifier/mister module. x1 ($2-8 for a set) Again, I got mine from a local China shop by taking apart an existing humidifier.
5. 12V power supply $6-10- make sure you are okay with cutting the end off it to connect it to the fan and LEDs.
6. Wires/Arduino jumper wires (depending if you want to solder or not)
7. Wago connectors x2 (optional) ($10 for a box) - This is not sponsored, but I personally love these and think they are the best solution. They make everything so much quicker!
8. Soldering iron - If you don't use Wago connectors.
9. Electrical tape (preferably black)
10. Cable ties (Zip ties) x2
11. Header Pins (optional)
12. Side cutter x1 (for removing support)
13. Hair spray can lid (to be used as a container for the humidifier's water)
14. A strong annoyance towards the flies and insects in your house.

Quick disclaimer. I have been testing my catcher for a couple of weeks before finishing this Instructable, but right before taking the pictures, the mister module burnt out due to using an unreliable power supply. As a result, the cover image has fake mist (gasp). Please make sure you use a proper power brick to power up your mister module!

*The fake transparent mist image is an AI edited picture of arso74's mist image from freepik. Just thought I should share this for transparency (see what I did there).

If you're not interested in learning about how this design came to be, feel free to skip to the next step!

The design of this flying insect catcher features a cylindrical housing with a PC fan and blue lights to lure the insects. It sucks in the air from the top and blows it out the bottom through a grid filter on the inside to catch the insects. It works extra efficiently as it has a stand to allow more airflow.

Note: the reason for the gap between the white grid holding the blue cone and the body of the fly catcher at the top (as indicated in the second image above), is due to the design process. I originally wanted to put the led strip above the white grid, but ended up putting it under as that would encourage the flies and other critters to actually go inside towards the fan. It works like a charm!

I designed it mostly using Blender for the complex shapes that required modifiers, and Tinkercad for the rest. I am still learning modeling, so don't criticize too hard!

There are some nice ones online that work similarly, but the problem is that they only have small LEDs which are only visible at certain viewing angles, so a design challenge was trying to include a mister module along with a less obstructive view of the LEDs.

But now that you have a method to rid your air of filthy pests, you now want to freshen it up a bit! So, I found a cheap $3 humidifier (200 milliliter) and took out the ultrasonic sensor and controller pcb. Alternatively you could just buy the humidifier module online, but this was the quickest solution for me.

You can really use whatever settings and filament suits you, but this is what I used for optimal strength/infill ratio:

Slicer: Creality Print

Filament material: ABS

Infill density: 15%

Nozzle Temp: 260C

Bed Temp: 100C

Speed: 200 mm/s (250mm/s for outside walls and certain parts of the infill)

Infill pattern: Adaptive Cubic (after slicing in all of the patterns, this one used the least filament).

Fuzzy Skin: 3mm, 3mm

Note:

For the fan filter mesh provided by wafflecart, I printed the one with the larger holes because the other one was not able to slice for some reason. Print this one a little slower at a .2mm resolution or else it will end up looking like mine... not great... Warning you in advance-this one is a tricky print.

Alternatively, you could still use the fly_basket_cone to hold an actual computer fan mesh in place instead of printing one!

Once finished printing, you should have these parts:

1. top_half_catcher x1
2. fly_basket x1
3. base x1
4. humidifier_cone x1
5. humidifier_liquid_container_lid x1
6. humidifier_absorber_holder x1
7. fan-filter-mesh x1 --Thanks to wafflecart on Thingiverse for providing this model.
8. fan_guard_and_trap_lid x1
9. fan_cone_and_seal x1
10. fly_basket_top x1
11. fly_basket_cone x1

fanGrill is provided here if you don't have one!

Please put the pieces together following the order of the images above!

For the fan filter mesh by wafflecart, just cut the corners off so that it will fit into the cylinder and cut a small hole in the center for the wires.

Take the fly basket, put the fan filter mesh in. Next, put the fly_basket_cone on top of the mesh to hold it in place and close the gaps. After that, put the base piece in the hole of the basket. You may need some electrical tape to secure the fit.

Then, take the wire from the power supply, cut off the end and strip it. Put it through the hole at the bottom of the basket extending at least 7cm (2.7in) out on the other side. Tape it on the bottom of the base ensuring that the wire goes through the groove.

Once you have that prepared, take the LED strip and put it in the top_half_catcher piece. Line up the strip's wires to the groove as shown in the picture. Make sure to put it in the groove that is straight with the sphere- not the ones at an angle!

Finally, insert the fan_guard_and_trap_lid part into the top half. Line up the groove on the fan guard with the wires on the LED strip.

For this step, you need to connect the fan wires and the 12V LEDs in parallel to the power supply as shown in the pictures and the super detailed and fancy diagram above :D

Note: I highly recommend using Wago connectors as it requires no soldering and it only takes a couple of seconds. The Wago connectors are connector blocks that allow you to just join two cables together instead of soldering them together and isolating the finished product.

The first image above shows how the Wago connector block works. However, you can solder the wires if you feel like you need to brush up on your soldering skills :D

After you have connected the positives of the LEDs to the positives of the fan and the negatives of the LEDs to the negatives of the fan, connect them to the 12V power supply using Wago connector blocks as shown above. The negative wire on the power supply should have white stripes on it.

Once that is done, go ahead and organize it a little bit using cable ties to keep the wires out of the way of the blades.

Next up, using your soldering iron, extend the wires of the humidifier module. Be careful with this as too high of a temperature for an extended time on the pcb can kill it. If you need help with soldering, reach out to someone who can help you or ask your parent/guardian.

Pro tip: when soldering on a pcb, a temperature of 360C (680F) is a good temperature if you don't want to kill your board!

Also, your wires to extend the humidifier's ultrasonic sensor need to be longer than mine for an easier experience. Mine were about 13cm (5.11in). It would be best if you can cut your wires to at least 20cm (7.87in).

Next step shows where to put the ultrasonic sensor + module.

Once you have cleaned up the wiring, insert the humidifier's ultrasonic sensor into the hole in the fan guard. Make sure to have the riht side facing up!

Next, take the fan_cone_and_seal part and slide it into the bottom of the top half. Line up the groove with the wires so you don't pinch them!

Once you have that sorted out (if you mistakenly used shorter wires like I did then it can take some patience), take the fly_basket_top part and attatch it to the fan. Then insert the fan into the top_half_catcher part under the fan cone. It should just slide right into the 4 corners in the top half part.

Close up the catcher by joining the two halves together using the interlock grooves. Twist anti-clockwise to lock it.

To setup the humidifier module, remove the fan guard. Put the spring and the absorber piece that came with your humidifier module and put it into the humidifier_absorber_holder part (spring first).

Next, fit that onto the humidifier_container_lid and close the container (hair spray lid) with it. Fit this onto the fan guard and slide the fan guard back into place. Be careful if you have this filled to the brim with water as it is easy to spill when inserting it!!

After just a couple hours of first testing this device, I managed to catch 6 moths, 2 flies, 2 mosquitos, and a flying ant! Using a sweet flower aroma in the air freshener/ humidifier really helps to attract flies as they are attracted to 3 things:

1. Decaying organic matter (and other pungent things)
2. Sweet scents
3. Blue/UV lights

So not only does it release a sweet smell (contrary to cheap DIY solutions with a plastic bottle) - it rids your air of filthy pests and humidifies it a little.

Now you have an aesthetic, quiet, low-cost, and low-maintenance fly catcher that runs on a .7w PC fan!

Enjoy your pest free life!