The breakout boxes sit on the racks with the rest of the surface electronics. Their purpose is
- to serve as an interface between the high density water proof cables, and the variety of more standard power and signal cables
- to fan out the low voltage power and calibration sine waves
- to communicate with the LVHV slow-control modules in the water-proof housings, using CANbus protocol
- to provide an additional handle for trip monitoring and to cut power to the waterproof modules.
There will be one breakout box for each LAPPD. The box design is shown schematically below:
The breakout box houses a Raspberry Pi for communications with the slow controls and communications with the DAQ. This Rpi has two "Pi-hats": (1) a CANbus interface and (2) a power relay which enables the Rpi to cut the power to the LAPPD. The rest of the Breakout Box design consists of terminal blocks and bulkhead connectors to take the wires from the high density waterproof cable connectors and reorganize them into power lines, signal lines, CANbus lines, and RJ45s.
We currently have a candidate for the box, Rpi, and both Pi-hats. We just need to finish the rest of the design and build 5 + 2 (spare) boxes.
The chosen model for the Rpi can be found here, and the Pi-hats can be found here and here.
We are currently using over-the-counter boxes, found here, for the container. They may be too thin to fit in the box with the two needed Pi-hats. We can either use wires to move the PiHats to the side or we will need to find a thicker box. Also, holes with need to be drilled for all of the necessary bulkhead connectors.