Open source Alienflight FC


@Stwspoon, I have allocated all the stm chips I have on hand, but I will be getting some more, so I can do one down the line. There are some other people building the F3’s, If you are in a hurry, they may be able to help faster than I can.


Joel, no hurry, just put me down for a quad and a hex board when they are available.



After @pedro147 had success with the F3 Hex FC I sen’t him, I built another for myself. Installed it on a SoSx Dragonfly V2 frame with MMW CL-0820-15 motors and a Lemon Satellite RX. I used a Boscam TX5826 400mW vTx, RMRC voltage regulator and Pico V2 wide angle camera for the FPV equipment and used connectors to make everything modular for easy maintenance. It’s been very windy here on the coast so I’ve only been able to do a couple of test flights inside but it flies nicely, which is a milestone for me thanks to Peter’s help for many months. Need to get it outside and record some FPV footage when the winds subside.

F3 Hex FC

F3 Hex FC and Lemon RX installed on the Dragonfly main plate

Boscam TX5826 400mW vTx, RMRC voltage regulator and Pico camera on the Dragonfly bottom plate

Finished build


A beautiful build as always @Hammer We will be praying for a let up in the windy conditions so you can show us what that Hex can do :slight_smile:


Hey guys, Thanks for providing all the info to make these boards! I have really enjoyed assembling these FCs. So I have made 3 F3 Quads and 3 of the Narrow Classic boards. All 3 of the Narrow classic’s came out successfully, but I have not been able to keep the F3 Quad boards working. The last board I made was functioning perfectly until I attempted to raise the throttle on my Taranis, and then something bad happened and now the board will not connect or allow for flashing and it is overheating. I believe it is only the Inductor overheating, and it gets hot enough to burn me. After I soldered all the motors on this board and powered it with USB the motors would start spinning immediately. I had to change Min Command to 0 in Betaflight 2.9.0 to get them to stop, and then after hooking up a Lemon RX and trying to test them the board failed. I think I changed min throttle to 0 and max throttle to 1000, so I’m not sure if any of that could have been a cause. I was just wondering if anyone had experienced a problem like this, or had an idea as to what part might be faulty. Luckily all the schematics are available so I will spend time looking over that if there are no solutions. Thanks!


Hi @hackn3y I am glad that you had as much fun as us making FC’s. I have not done any F3 FC’s yet only 8bit.

If you feel like joining a small group of guys making these FC’s and sharing their experiences and knowledge, come on over to our Facebook group FC builders and Hackers Cooperative we would love to have you join

I am Peter Newman there :slight_smile:

PS - The most active members of this thread are also over there Right guys


Yeah, come over to the groups also @hackn3y.

As for your incident/issue with the F3, not had that happen myself. Is there any visible damage? It sounds like you might have a short somewhere.


@hackn3y signed up on Hacker’s today @JG101 :smiley:


I probably commented on his welcome post too, I am a bit slow sometimes lol.


Definitely a short somewhere. I’d start probing around with a tester looking for them.


No obvious burn marks unfortunately, not sure how it happened since the motors didn’t even spin when I did it, but I will just start probing around. One of my other boards was overheating the same way, and it seemed to work fine in the GUI, but I couldn’t get it to spin the motors and the other just didn’t want to connect to the GUI even though it would go into DFU mode and flash the firmware. The 3rd board was definitely my best and came out of the oven with no shorts, but thanks the responses!


Hey @hackn3y, I have had a similar issue. Are you sure it was the inductor that was heating up and not the Buck Boost chip? Power flows through the buck boost and to the inductor, i am not sure that a short in the buck boost would overheat the inductor but essentially if too much power is going through that inductor it would get very hot and that would be a short on the upside of that inductor allowing power to flow right to ground i would think. Trace the schematic from where the power flows through the inductor to the next components if it is the inductor getting too hot, if the buck boost is shorted under the chip it will also get smoking hot is why I ask if you were sure it is the inductor.

Edit: I was looking at the .brd file for the F3 quad and if the buck boost was shorted somewhere under the chip which can happen if there is too much solder on that ground pad under the chip, power could flow directly through the inductor to ground. My experience in all this has been that even if all the connections of a chip look fine there can still be issues. A lot of the guys have been using the poor man method of building these and the advantage there is that you can place just the MPU, STM and buck boost so that they can be more easily inspected. It could be done with a reflow oven in the same way. If all the chips are placed first they are not only easier to inspect but they are also easier to rework. On that buck boost chip it is important that it only has a tiny amount of solder on that pad under the chip. I have come to the point where once these main chips are in place that I flux the pads and pins of the chips and then drag solder them before even trying to place any of the other components. Whether they look good or not because I have been rounds with these chips and when a card is non functional or acting up it has been almost 90% of the time the MPU or STM/Atmega.


It was the buck/boost converter, shorted underneath like you mentioned, and I damaged it, which made things more difficult. There was something going on with the inductor or possibly a tiny piece of solder mask that was removed underneath it preventing the converter from outputting 3.3v. I think I’ve got it fixed now, and I was able to boot back into the GUI so I just need to test the motors and hopefully strap it on a frame and take it for a spin. I’m guessing I have the same issue on my other board(s). Thanks again!


Glad you got it sorted @hackn3y

This is why Adam alias @madman1412 is The :alien: Doctor

@Jtwalkz and @JG101 are shaping up nicely too :wink:


I’d say that @Jtwalkz and @JG101 have me hands down on the technical understanding of all this and all of you in general have passed me in knowledge with all this. I am just happy that I can still help where I can from the experiences I’ve had in all this. I am no guru but I’ve had a little education in how to make these FC work. I will not give in on a non working card, maybe my downfall maybe my strength :blush: I am just a small part in all this. It’s the group effort that really makes a difference.


Appreciated but slightly overstated praise @madman1412!


Hey @JG101 we will decide what is overrated around here thanks :smiley:

Your FC building and diagnostic skills are right up with the best that we have to offer


Yeah like @pedro147 says, I am not overstating your skill :wink: You are way smarter than I think you let on mate. I have been watching.


Hi Joel,
I’m going with a couple of Microflitw pico FC boards,
so please take me off your list. Thanks



No issues. Those do look like great little FC.