In the last few days I've done a lot of small work, but nothing big on any particular component. I have been writing quite a bit of code. I'm writing the ROV's control software in C, which I've never used before. I do have a fair bit of experience with C++, and most of the work I'm doing is pretty much the same in both languages. I've pieced together chunks of a few linux utilities and filled in the gaps with my own code. At this point I think the ROV will communicate with TCP. I've already implemented TCP and it's working just fine, but now I'm looking at DTP and some other data protocols that would probably be much faster, but the network will be a closed system with two nodes so it shouldn't be that big a deal. We'll see. I've also set up the basic framework of the control system. The control program on my laptop takes signals from the Dualshock3 and converts them to motor speeds and other control values. The laptop program sends these values as TCP messages to the Beaglebone which currently doesn't respond. I might have it send receipts, but that seems unnecessary at this point. The laptop and Beaglebone do send heartbeat signals every second. That's what I have so far.As far as mechanics are concerned, the only work I've done is playing around with the syntactic. I'm planning on cutting out 1000 small loops, about the size of cheerios, that will string over the tether like beads every one foot. I cut my first test batch a few days ago.
I cut my block of syntactic into small sheets with a table saw then milled them flat to a thickness of 0.500".
Then I cut out a test pattern with a waterjet. I figured this would the fastest way to cut out 1000 of them with the least possible waste, but then I found out the cost. $3/minute. This test batch was free and it will be the only batch I cut using a waterjet. I'll do the rest with a CNC mill that doesn't cost me anything.
On top of that, the cuts weren't particularly clean. I didn't have the board properly weighted down, so it was vibrating a bit, but the waterjet was tearing out chunks of foam instead of shearing cleanly. I wouldn't recommend cutting syntactic this way.
That's it for now. I just received my motor speed controllers so hopefully I'll have time to mount those on the Beaglebone cape this weekend.