[Jon Stratis]

Originally Posted by kmusa

I don't believe anyone restricted this to only software interlocks.

For instance, two limit switches in series (which require contact from the ball to close), and connected in series with one of the leads for the solenoid would be robust, and not open to software override.

-Karlis

And would be illegal per R53:

CUSTOM CIRCUITS shall not directly alter the power pathways between the ROBOT battery, PD Board, motor controllers, relays, motors, or other elements of the ROBOT control system (items explicitly mentioned in R64). Custom high impedance voltage monitoring or low impedance current monitoring circuitry connected to the ROBOT’S electrical system is acceptable, if the effect on the ROBOT outputs is inconsequential.

Note that R64 mentions the solenoid breakout as part of the control system.