[KenWittlief]

when the robot is powered but disabled by FIRST field control system at the start of the match, the inputs are still being fed to the robot, the inputs from the user interface, and any analog or digital inputs on your robot itself. Only the outputs are disabled, that is what keeps the robot from moving until auton mode is started

so you could have your bot look for the auton or regular play bits to not be set yet, and use that time to calibrate your sensors. Your bot will always see several seconds of 'disabled time' after its been turned on, and before auton modes starts.