Motor arm/disarm with a radio switch

Good day i know this topic has been brought up before, feature requests have been submitted. I wanted to ask again. Its 2016, ArduCopter 3.4 is in development. Has the ability to motor arm/disarm with a radio switch been added yet? I use other flight controllers with different operating systems for example Cleanflight and LibrePilot. They all have the simple ability to arm/disarm your motor anyway you like. Please don’t ask why i would want to do this, my reasoning doesn’t matter. Its a standard feature with other operating systems; i don’t understand why i cant do this yet with ArduCopter…

Does any know if this can be done yet?

Is this what your are looking for ?

There is the Motor Interlock and Emergency Stop Motors functionallity but i did not test it.

1 Like

Very close to what i am looking for. Did you notice the throttle down and to the right for 5 seconds. I do not want to arm that way. I would like to arm /disarm with the a switch just like he shutdown the motors.

Hi James,

ok i am not 100% sure but i think we dont have such feature for arming / disarming with a switch. I could be wrong though but didnt find it with google’s help.

Hopefully someone else can shine some light on this.

You can send the arm command from a ground station. Mission Planner and Tower for example have buttons you can click to arm. But there is no way to map an RC input to arm/disarm


I am familiar with the ground station and tower app arm/disarm feature. I was hoping by now 3.4 dev version would have the capability to perform the arm/disarm with a switch in your radio. So many other flight control operating systems have this capability.

I can definitely understand the desire of the OP for designated arming/disarming via switch. IMHO this would be good usability improvement, best combined with a Stabilize mode that is zero-throttle proof for emergency descents without losing attitude control.

1 Like

I’m hoping one day this will be a possibility.

This branch implements arming/disarming uby setting CHn_OPT to 39:

Essentially it attempts to arm (once only) if it sees the switch asserted. If arming fails you can re-try by de-asserting the switch and then asserting it again.

If the copter decides that it has landed and the arm/disarm switch is de-asserted then it will immediately disarm. Since we have had incidents where the vehicle has thought it was landed while merrily flying around, it would be a bad idea to have the arming switch de-asserted while flying.

Flown only in SITL. Considering bugs will cause your vehicle to plummet onto nearby cute fluffy bunny rabbits, fly with caution.

Would this meet your expectations for such a switch?

1 Like

I think it will. When will this feature be added?

Well, I’ve created a PR, so now it’s up to Randy:

I put this on a vehicle. While I couldn’t fly due to a bodgy ESC, it did seem to behave as expected/described.

1 Like

I would expect the switch to instantly disarm the vehicle, without regard to the landed state. Reason: I had quite a few crashes ending with the vehicle digging for gold for a dozen of seconds, at the 2kW power setting, roasting motors and ESCs and smashing everything else that survived the crash itself.

1 Like

The ESC Humane society requests you investigate the motor interlock feature. I’ve always got that on my multicopters now-adays.

I would prefer people who want to arm their vehicle with a switch to then have a one-switch-kill button on their vehicle. That’s what interlock is for.

That being said, apparently a lot of the other autopilots out there do just fall out of the sky when the switch is toggled in-flight.


Patch has changed so that the vehicle doesn’t need to be landed to disarm.

Your vehicle will fall out of the sky if you toggle the switch in-flight. If you inadvertently invert your vehicle on the ground you can stop the props with the switch.

Just to get it right… If i take this function on a switch and trigger this switch the copter will stay armed as long as the switch is in the high position? As soon as i switch it back to low the copter will disarm right away?

I s there possibility to change method of arming/disarming motors ? I would like to arm motors by putting two sticks on radio to lower right and disarm motors by putting two sticks to lower left corner.

I agree with this, switch-arming is extremely useful. On the FC, it should be implemented as just a channel being high meaning “armed”, and the channel being low means “disarmed”. Then each user can configure their radio however they want so they can arm, in my setup, for example, I need to flick the “arm” switch and hold down the momentary switch for two seconds to arm, and flicking the “arm” switch back immediately disarms. It has saved my hide more than once, and I just wouldn’t fly a quadcopter that couldn’t be disarmed immediately.

We have this… near enough. It’s the transition which is detected, not
the position. So if the vehicle fails to arm (e.g. no gps lock) then you
need to move the switch to disarmed and then back to armed to try to arm
again. You can probably imagine why it is done this way.

Yes, that is the right way to do it. Thank you!

Is it available now? Can I use it?