Low Voltage alarm is triggered when the voltage is at least 3sec below the min value
Makefile fix
Patched PX4IO ADC to work. See https://github.com/diydrones/ardupilot/issues/653
Moved to ArduCopter v3.1.5 release
Added Tridges patch to fix logging on PX4. See Ardupilot commit f222f2ef1e68ec528148de2bf32eb256fa00db4f