Connecting mower to USB makes it start mowing

[thomasloven]

When the mower is connected to a computer using USB, the arduino starts running the normal program.
Depending on the choice of motors, this might make the weels turn, or even start the cutter - probably not something you want hapeening on your computer desk.

A possible solution might be to check the battery voltage at startup, and if it is below some threshold, start debug mode. The threshold should probably be chosen a bit higher than USB standard 5.0 V to accomodate for a badly adjusted trimpot.