Mike Shellim 26 April 2016
Here's a recipe for a safe arming/kill switch for an electric motor. It's designed on the premise that arming the motor should be difficult, and killing it should be easy - but not so easy that you can do it accidentallly.
It's based on the safety switch recipe with a couple of mods.
To kill the motor:
The system is implemented as a bunch of logical switches, see screenshot below. Key points:
Here's the suggested mixer setup for controlling a motor on CH3:
How it works:
[Aside: an alternative method is to have the motor active by default, and use the Override special function to disable it. However, I don't recommended this, as the Override function is applied at the very last stage in the command pipeline, and has no effect on the raw channel outputs. This can cause problems if you reference the motor channel elsewhere in your setup e.g. to detect if the motor is running. The method shown above is more explicit and easier to debug.]
The following demo shows the arming/kill switch operating on CH3.