This is an FPV antenna stabilizer to solve a problem of having very bad radiation pattern when turning with plane. Plane turns take a lot longer and they fly further away than multicopters so this was very noticeable and disturbing.
This is only 1-axis gimbal so it only helps on a roll axis, I designed this with my Mini Talon in mind so it should be good for peaceful cruising.
The design is also very slim to fit my specific need but I think this way it could be also easily embedded into a frame if needed.
Of course this could be used on a pitch axis as well but I doubt that would be as useful.
(Instructions are for INAV only, version 2.0.0 or later, I have not tested this with any other firmware. Doesn't mean it wouldn't work tho.)
Full 180 degree rotation.
What you need:
- 1x MG90S or similar 9g servo with 180 degree rotation.
- VTX with flexible cable
- 1x M3*6mm screw with one little M3 washer
- Ziptie to secure servo cable if needed
After you have printed the two parts, start by screwing the servo arm in place.
Note that you must put the little screw between the servo arm and printed part before screwing it in.
Center the servo before this!
Mount the arm assembly the the servo through hole on the other side.
Then put it all together.
I put a small washer between the two printed parts and used M3 screw as a joint.
Put the SMA connector in place and secure it with a nut, or the antenna itself.
Mounted on my Mini Talon.
Had to ziptie the VTX to the side because there was no other good place for it.
After building, setting it up and connecting the servo to free slot on your flight controller you should be good to go after these small configuration steps.
This configuration basically uses a camstab feature on INAV which is designed for camera gimbals but I don't think INAV cares what it is waving around.
There are three different things you need to do in the configurator in order to make it move.
Enable CAMSTAB from the modes tab.
It should not matter which channel it is on since you probably want it to move all the time, spread the trigger range to cover the whole range.
If, for some reason, you don't want it to move all the time then do something else.
Then go to the Mixer tab. Add new mixer rules and set them for the servo which you have connected to the stabilizator, in my case 6. Set input to "Gimbal Roll".
But why is there two of them?
For some reason as default (if there was only one mixer rule) it would transfer full 360 degree spin of the flight controller to 180 degree servo movement, so it did not move enough. INAV also doesn't accept weight or rate value bigger than 125%.
By adding two of the same mixer rules INAV seems to just add them together.
100 + 100 = 200 ¯_(ツ)_/¯
This seems weird and it is possible this is fixed or changed in the future because I already found issue posts about this on Inavs github.
However, this is how I got it to work.
Third and last is the Servos tab.
Here you need to set the MIN and MAX values according to how much you want/need the servo to move. For me it was full 180 deg turn so from 500 to 2500. I also needed to set the Rate % to 125.
If you did everything right and I didn't miss anything it should work now.
Because it's winter now I have not tested this yet in real world but I don't see why it would not work as intended.
If you make this, post a make and tell how it worked!
(Will do some DVR footage comparison when I get out to fly with this and will update it here then.)