Airsoft antifog fan unit

This aims to eliminate fog by using two tubes to constantly blow air into your goggles to clear fog by keeping the inside temperature of your goggles the same as the outside.

This costs around £35 to build from start to finish, you can save a bit on the battery by opting for a smaller capacity as 1000mAh can last up to 20 hours on low which is overkill if you're only doing a day of airsofting.

For this project you will need:

£1.78-Small form factor step down buck converters set to 5v
https://www.ebay.co.uk/itm/165356103314

£3.49- 3 Position rocker switches (Hole size 13mmx17mm)
https://www.ebay.co.uk/itm/123247349194

£4.25- 5V 5015 fan
https://www.ebay.co.uk/itm/283565508178

£14.99- 1000mAh 7.4v lipo (Can use lower capacity, will last over 12 hours on high)
https://www.amazon.co.uk/URGENEX-Battery-Batteries-1100mah-WLtoys/dp/B08Y8ZJ94K/ref=sr_1_6

£6.49- Tubing (I've used silicone however you can use PVC but it will be harder to push onto the nozzles)
https://www.amazon.co.uk/sourcing-map-Silicone-Tubing-Transfer/dp/B085N1W9K6

£1.29- 2x 10ohm resistors in series / 20ohm resistor
https://www.ebay.co.uk/itm/263898843941

£1.95- JST male connector
https://www.ebay.co.uk/itm/283619131459

£2.59- 2x M4x20mm screws
https://www.ebay.co.uk/itm/383632777744

Total:
£36.83 +filament/resin

You can see how the wires are laid out in the image above, I've used longer wires and a larger switch to make it easier to see but that's the general idea.

Make sure when soldering to keep the wires as short as possible as there is limited space in order to keep the unit compact.

Before soldering the fan to the circuit, make sure the wires are pushed through the small hole between the fan space and the electronics space.

After this you can solder the fan to the buck converter and switch outputs.

After this the buck converter can be slipped through the switch hole and then the switch mounted in place.

Finally ensure all wires are at the bottom of the electronics box so there is sufficient space for the battery at the top.

Finally the lid can slide into position, it should initially be stiff however after sliding it in and out a few times it should be easier but also not fall out.

There is a hole so you can secure the lid in place with a M4 bolt however if the lid is tight enough it should stay in place.

I suggest making a tab to pull the battery out by taping two pieces of electrical tape on either side of the battery or else it could get stuck. This tab can be folded down when closing the lid.

When printing the nozzles, I opted to use resin as it meant the small details came out clearer and had a better chance at fitting. However if you want to FDM print the nozzles, I would suggest a strong material like PETG and a small layer height of around 0.1mm to ensure the details are kept and it won't snap easily.

I've used part of an old set of mesh eye pro with two holes cut in it as a bb guard for the fan