Auto disarm does not work after landing if throttle is above zero

I just found out the hard way that there is a problem with disarm and now have some nice razor slices on my arm. I have the “spin props while armed” thing disabled.

What happened is the battery low warning came on. I was in loiter mode and took the drone in to land. Usually the drone will auto disarm. This time, however, it did not as the throttle was slightly above zero. Let me be clear: the drone had landed (and Arducopter told me so) and the props were not spinning.

I went to pick up the drone, assuming that it would have auto disarmed (yes, I know this is extremely bad to do without checking the drone is disarmed first, or using the disarm switch - a bad habit I have unlearned!), and the props started spinning despite it having landed.

This appears to be a bug. If the drone thinks it is in the landed state, it should ALWAYS disarm after the set interval.


Please attach a log.

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Password is my username. The disarming issue happened right at the end of the flight a minute or so before I disconnected the battery. Thanks.

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The props were not spinning because you engaged the Motor Emergency Stop (on Rc7). It was not disarmed at this time. Then it was disengaged and presumably picked up starting the props spinning. After chewing on your arm it disarmed from crash detection, perhaps when you dropped it. That’s what I see anyway.

This a bad idea:

I have motor emergency stop set to a momentary switch. I’m certain I was not holding the motor stop when I went to pick up the drone.

I engaged the motor stop as sometimes my landings bounce so I get ready to kill the motors to speed up the landings and make them more effective.

So are you saying the motor stop may have prevented the auto disarm, or delayed the auto disarm?

I have seen that if the throttle is above zero after landing (no emergency stop involved), there is no auto disarm. This is what I consider a bug…

Also, surely ARMING_CHECK=0 is a good idea because it means all checks are done before arming can proceed?

Yes, I think so. You momentarily pushed it but as soon as you released the button the motors are active again. I don’t think it makes sense to use a momentary switch for this function.

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It means NO checks are done if it’s set to zero. 1 is all checks.

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Wow, I have no idea how that came to be. I do not recall ever changing ARMING_CHECK from the default. I have fixed that now.

I would still argue that this is a bug.

Killing motors with emergency stop should not cause the auto-disarm to fail.

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If you want this feature just setup a mixer so that the kill switch also disarms the aircraft.

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That would work - thanks, good suggestion. I don’t have the time (or maybe knowledge) to make a patch to the source at the moment but I really think emergency stop should not prevent auto-disarm.

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