Our ROV build is progressing nicely. However, we have encountered a problem running the motors at full power in water. Here’s a synopsis of what we have setup.
We’ve successfully wired all our motors into the water tight enclosure, along with the ESC’s. Everything is watertight, and there are no short circuits. To control the motors, we’ve used a a CATe5 cable to transfer UDP data from a Raspberry Pi 2 on the surface to a Raspberry Pi 2 in the tube. Other electronics in the tube include an ethernet switch, an Adafruit PWM Board, and a couple of buck converters to step down the 12V for the Pi and the switch. The motors receive their power from a 12V power supply on the surface (which has a maximum output of 25A) through approximately 70ft of thick, insulated copper wire.
Running the system above water doesn’t yield any problem. When we tested it in water, the system failed. Applying continuous almost full throttle (roughly 80-85%) to more than one motor at the same time causes the code to freeze on both Pi’s. The Pi’s themselves don’t freeze and they do not shut down or reboot. Detaching the motors and sending the same signals does not cause the system to freeze.
We think the problem may have something to do with the load the motors undergo beneath the water, and the current they draw. We’ve attached the code below. Any help would be greatly appreciated!!
xbox_client (21.5 KB)
xbox_server (17.9 KB)