Ch7 and Ch8 Output Problems

I have been trying to figure this out for a while now with not much luck. I built a retractable landing gear for my hexa and I would like to make it retract through channel 7 or 8. 

If I connect the landing gear to the receiver directly, and switch the Ch8 switch on the RC transmitter, the gear retracts as it should. So we know the Transmitter and Receiver as well the gear are set up correctly.

I tried CH7 as well, because I found some posts that it has been dedicated for camera trigger control - but no luck.

Here is what I see. In Mission Planner RC Configuration I can see the input coming from channel 8 properly. I also can see that on the first screen where the Status are with the lots of numbers page. The values on Ch8in change as soon as I flip the switch as it should. However the ch8out never changes from 0. I went to the standard parameters page and I changed CH8 Function from "Disabled" to all of the possible option from that list - and none of them will give me any output on the ch8out.

What am I missing? How can I get standard PPM pulse output on Ch8 which corresponds to the PPM in coming from Channel 8 on the received? I know I can wire around the APM and do it directly - but cmon' that is not really a pretty solution.

I have the APM 2.5 version with the 2.9.1 Arducopter installed.

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  • MR60
    Just have the exact same question and issue: the ch7 camera trigger feature does not work.
    Like you when i by pass APM, i have a functional servo activated with the flip of a switch on my transmitter. As soon as i try to do it with ch7 of the receiver connected to the input 7 of APM, nothing works.
    We cannot be the only fools trying to use this basic function. Anyone who made it work could help?
  • Developer
    Try looking at this parameter to set ch7 as manual

    Also the outputs for arducopter are configured at 490Hz for faster response so are only compatible with digital servos.

    I haven't found a parameter to change the output back to 50hz, Ch11 Ch10 do work at 50hz
    But only connect the signal lines for the servos, take the 5v power/GND from the PWM outputs.
  • Nobody has any idea on this.
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