Here is a brief overview of the circuit board found on the ROV. Perhaps the best way to start is with the schmatic.
A higher resolution version of the schematic can be found here
Aside from the PIC16F1937, the three additional ICs on the board are the MAXIM RS232 transceiver as well as two quad AND gates. One of the AND gate ICs handles forward PWM signals and the other reverse. Being that there are four of these AND gates on each chip, each of the 4 corner mounted thruster motor ESCs is connected to both a "forward" AND gate and a "reverse" AND gate. Since only two different PWM signals are ever needed at one time (not including up/down movement) the AND gates are a simple way to direct these signals to the appropriate thruster ESC.
The board is currently bakelite/perfboard material with the hopes of having a pcb fabricated once further testing and additional features are added. Additionally, the board is mounted on a tray made by Blue Robotics that fits neatly inside the 4in. diameter waterproof acrylic housing.
The underside of the tray contains all of the ESCs and corresponding connections.
The ESCs are towards the front of the tray and held in place with a crude, makeshift holder.
Each ESC contains a protective fuse as well.
All wires entering both the main and battery compartments are sealed with the Blue Robotics pass-through penetrators and Loctite marine epoxy. There is also a pressure release valve for each housing to allow for pressure equalization prior to submerging.
That is the general concept behind the physical aspects of my ROV circuit. There are certainly an endless number of methods that could have been used besides the one shown here so feel free to experiment. Next up we will begin to look at the microcontroller code for the ROV vehicle.