It's been a while since the last update due to a number of technical issues that needed solving, not least of which was a valuable lesson on good soldering. This is the replacement power management board, the prototype worked but was missing the P-channel mosfets. These allow the Pi to shut down the rest of the head systems to save power, and should automatically shut them down when the Pi is turned off.

To try and solve the sensor fluctuations, I'm working on a seperate board to power the sensors from, with seperate lines for analog and I2C, and some capacitors to keep the noise out. Then to keep everything stable and to attach the top of the head, I've redesigned the circuit holders to use m8 bolts instead of plastic pegs.

Aside from all the rebuilding in the head, the external power connector is almost finished. This is designed to fit snugly into the battery slot and connect to a standard 12v dc plug.