Launch Detect From IMU

[natronics]

We're unlikely to have hardware launch detect, so it needs to be implemented as looking for high g's while in ARM state.

If g > threshold and ARM == true, then 'launch detect'

We expect threshold to be around 4 g 'up'. No debounce.

Debug: There also needs to be a debug backdoor to trigger it for testing.

[keith-packard]

Nathan Bergey notifications@github.com writes:

We're unlikely to have hardware launch detect, so it needs to be implemented as looking for high g's while in ARM state.

If g > threshold and ARM == true, then 'launch detect'

You'll actually want to integrate this a bit and look for
velocity. Bumping the rocket can easily cause a false launch detect
otherwise.

I look for height change by 20m || (accel > 2g && speed > 5m/s).

-keith