Quote Originally Posted by VictorV View Post
The parts I used are:
Ray Allen G405 Stick Grip: https://www.aircraftspruce.com/catal...clickkey=41355
Ray Allen REL-1 Servo Relay Deck: https://www.aircraftspruce.com/catal...lickkey=852685
Garmin GSA-28 Servo: https://www.aircraftspruce.com/catal...h_11-11450.php
TCW Safety Trim Booster: https://www.aircraftspruce.com/catal...clickkey=17761
Kitfox-supplied Pitch Trim Servo

Note that the Pitch Servo (Garmin) and Pitch Trim Servo (Kitfox-supplied) are 2 different devices. This design only applies the devices listed above.
The system is based on the G3x Autopilot. The key problem that has to be solved is to convert the stick grip button signal (depressed=signal to ground)
to the reverse polarity signal needed by the pitch trim servo.

The key points that drive the design are:

1) In the Ray Allen grip when a button is depressed it connects the signal to ground.
2) The Ray Allen grip buttons can only handle 1 amp and the pitch trim servo draws 2.5 amps which is
why the servo booster is needed.
3) The pitch servo has trim outputs so that the autopilot can control the trim as well.
4) The trim outputs from the Ray Allen servo deck are combined with the autopilot trim commands
in the Garmin pitch servo.
5) The combined pitch servo trim outputs are then fed into the TCW Safety Trim Booster to create the signal to
drive the pitch trim servo.

The simplified diagram is:

Screen Shot 2024-04-30 at 10.26.41 AM.jpg

I skipped trying to figure out how to use the Kitfox-supplied trim switch along with the stick grip switches because
it seemed too complicated to implement.

If you're not using the Garmin Autopilot/Servos you can connect the output of the servo relay deck directly to the
TCW Safety Trim Booster.

The installation instructions for the 4 devices provide enough info to create the wiring diagram. I don't have one
that I can attach unfortunately. If you need more detailed help let me know and I'd be happy to help out. Since
I have not flown my KF yet I don't know for sure if everything is correct but the trim up/down buttons on the
stick grips are working as expected.

Victor
This is perfect man. I'm going to copy your design here, only difference is substituting the Ray Allen relay for the VPX, otherwise same same.