FatShark HD3 FPV Goggle Fan Mod

The fatshark googles are some of the best FPV goggles you can currently get, but it is not without itsĀ nuisances. Luckily there is usually a fix, and for us one of the biggest annoyances of the goggle is with the fan.

The fan on the FPV goggles is one of the main reasons we decided to upgrade to begin with as it prevents the lenses from fogging up. But in order to use the fan you need to plug in an additional connection into the fan from the battery. Sure this isn’t such a big deal, but after doing it over and over it just becomes a small but very annoying hassle, not to mention even if you do remember to plug it in you still have to press a button to start it. So why not fix it? I mean how hard can it be to just run the fan off of the main voltage of the battery?

Well for starters the goggles can handle a higher voltage than the fan can, so connecting the fan directly to power will remove the option of using a different battery like a 3 cell. So the way to get around this issue is to use a regulator. After some googling and research through the manual we decided on a 5v step down pololu regulator, we decided to go ahead and risk the chance of it causing noise in our video feed. If we end up with some noise we will either remove it or try to wrap it with something we can ground to stop the noise.

In our research we have seen some videos and forums of other people doing this same mod, but they keep the timer and the connector on the outside of the googles, this to us looks pretty messy. We want our fan to run as soon as the battery is connected, we do not want to keep remembering to push the small button every five or ten minutes. We also want our wires to run internally so its nice and clean.

We started by removing the video receiver modules and head strap.

Remove the small screw by where your nose sits, once removed you are able to carefully pry off the fan mount.

Now remove the three screws from the bottom which hold the goggles together and open the halves carefully.

Once apart we figured out what our best option was to route the wires, we originally imagined being able to remove the timer board and replace it with the pololu in its place but it didn’t fit very well as the mounting screw would have to go through the board.

So we decided to just extend the fan wire and route it to the power input and just have the pololu board rest inside the module bay.

We drilled a hole through the fan mount bracket near where the head strap mounts as we saw there was a path into the module bay from there. We really should have used smaller wire and thinner heat-shrink but that is all we had to go with at the time.

Once we had the wire routed where we wanted we needed to solder up the pololu. We wanted the goggles to be easily opened again so we used a 2S connector we had on the pololu so we can disconnect it in case we needed to open the goggles in the future.

after adding some conformal coating and heat-shrink we needed to find a place to solder the power and ground. We used out multi-meter to confirm we were taping into the right areas but decided it would be easier to just solder right onto the barrel power input plug.

We added some hot glue to the back of the input barrel plug because it was tough getting a strong solder. We may have to go back in and solder the power lead to where the barrel plug is soldered to the board like we did with the ground.

We used out multi-meter again to make sure we had no shorts from the center pin of the barrel plug to the ground.

So now the fan runs right off of the battery with no second connector, it is 3s capable just like the googles, and its a nice and clean set up, from the outside at least.

After it was all assembled and ready to go we checked a few more times with the multi-meter and saw we had a short, we started taking off the modules and checking again and discovered that the La Forge V2 diversity module was touching the top of the power board. Not sure what caused that change as it worked before with no issue and the board was reinstalled just ad before. We used some conformal coating and kapton tape to protect the board and the issue was resolved.

Now we have a set of nice and clean FatSharks for FPV! While we did the fan mod we also ran the La Forge diversity wire internally.

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