How to hibernate for 2 hours w/o disarm and then fly

PX4 Autopilot
1

Hello - my son and school mates are working on a project where a drone will be shot in a rocket. From the time they have to put it in the payload to ejection is about 2-3 hours. Their current plan is to arm the copter, let GPS lock and stabilize, and then hit the “kill” switch so that no props are spinning.

Once the copter is ejected, it will fall via a parachute at which point they will let the parachute loose and start the motors to fly to a target.

In their testing, they have determined that after a period of time (15 minutes or so), the flight controller and ESCs make tones and the props twitch. When the kill switch is undone nothing happened until it was disarmed and then armed again.

So, questions:

  1. is there a timeout on the Kill switch? If so, is that configurable?
  2. is there an alternative method you would suggest? The presumption was that arming in free fall wouldn’t work and it would need to be pre-armed. Perhaps turning the PWM on throttle down so there is no spin and leaving it armed.
  3. Others?

Thanks in advance. They are using a Pixhawk 1 with the latest firmware.

2

Hi @jrowe88 ,

Yes, there is a safety timeout that disarms the vehicle when it is killed for more than 5 seconds. I would have to check if this is hardcoded or if it can be disabled by a parameter.
You are right to think that the risk of the drone refusing to arm while suspended to a parachute might be quite high.