Different throttles for switch and stick arming

I’ve been building a minimal 3D printed quad with ArduCopter 4.1.5 on a Matek H743 slim board, and I tried setting up an arm/disarm switch by setting the relevant channel option to 41. Which works, arms/disarms nicely, and disarming is faster than stick disarming.
The one strange thing is that when arming with the stick, the motor turns at the throttle % set in the motor test section, but when arming with option 41, the motors at a lot higher rpms. I have no idea what causes this and how to change it. Any thoughts?

Interesting observation. I don’t use an Arm Switch for Multirotors but I tested this on a 4" on the bench and see the same thing. On this quad ~1000 rpm stick arm and ~5000 rpm switch armed. Not enough to lift-off but troubling anyway. I believe what you are seeing is expected behavior for 4.1.5. Switch arming=Airmode.

On my quad, which is running 4.2.0 beta 3, If you enter 41 it updates this to 154 (Arm/disarm with Airmode) with a reboot. Then it’s running at Throttle Min at Arming. If you use 153 it will Arm at Arming throttle.

@rmackay9 perhaps you can check this out. Should this be updating to 153 and not 154? Perhaps so to keep the same logic as 4.1.5?

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As @dkemxr pointed out the difference is airmode.

Pre 4.2 arming with switch always gives airmode.

On 4.2 you now have two options, Arm/disarm with Airmode which is the same a 4.1, and Arm/disarm this is the same a stick arming, no airmode.


Thanks, that seems to explain it. So I’ll just stick arm/disarm and add a motor kill switch for emergencies.

Or update to latest Beta and use the new setting!

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Might play around with that later, but for now I’ll stick to the stable release :slightly_smiling_face: