I have just mounted a jdrones gopro gimbal to my stock 3DR quad and have a strange twitch on channel 6 for the pitch control.
When sitting on a desk, the pitch twitches once every few seconds (less than 10). If I look at the radio input I can see the twitch there most of the time but only if there are a few twitches in quick succession. A single twitch hardly shows compared to quick succession where it goes almost full scale.
If I look on the radio (Spektrum DX8) the monitor output shows nothing. Oddly, the tuning graphs also show nothing for channel 6. When I flick the switch between the three positions the graph moves as expected.
Finally, I put a spare servo directly onto the receiver channel 6 and no twitch from it. Nudda. Zip.
So, radio says there is no twitch. Server connected to the receiver shows no twitch. MP tuning graphs shows no twitch.
Radio input on setup shows twitch. Pitch servo for camera responds to twitch.
if I swap to another channel, the problem goes away...
Really confused. Any help please :)
Latest 2.4.1 firmware loaded onto APM 1 (2560)
Ch6 Opt in MP is set to CH6_NONE
What's the blue thing between your spektrum receiver and the APM? Is that something like a spektrum adaptor or something else?
That is my zigbee infront of the spektrum receiver.
Ok, the zigbee could be the problem. I've heard reports from Robert on the dev team that a zigbee can cause interference with his tail servo. Would it be possible to remove teh zigbee and see if the spikes go away?
Check if this: http://code.google.com/p/ardupilot-mega/issues/detail?id=508 seems to be related.
I've seen noisy output for no reason.
I also have twitching pitch/roll servos but I observe it became much stronger during the flight. Servos twitch all the time! Interferences or what? Everything is powered separately from other BEC, there should't be any brown outs.
I analyzed PWM signal from APM and it looks very distorted when moving the throttle stick (Even when I repleaced ESCs with servos), like that:
I have APM2 for arduplane, but i have a twiching servo (6) too, I noticed that telemetry port is very close to outputs and if a servo cable come closer than 1 mm to the telem port then it starts twiching. i wrapped and twisted my servo cable, added a ferrite to xbee cable and the twiching is gone.
By the way, servo function = 1, doesnt pass thru signal for my APM2 like i did with APM1, any ideas?