Tidying Up The Engine Room

I’m tired of sailing my little boat
Far inside the harbor bar --
I want to go out where the big ships float
Out on the deep where the great ones are.
And should my frail craft prove too slight
For waves that sweep those billows o'er,
I'd rather go down in the stirring fight
Than drowse to death by the sheltered shore.

-- author unknown


Two weeks ago I posted a picture of the inside of AMOS after it had been driven home in the van from a test and some of the components had shifted around a bit:

Although the above picture exaggerated the usual condition of AMOS's innards, it wasn't too far from the usual reality. It had gotten to the point where I seemed to be making repairs to the wiring as often as not, and it was time to straighten things up a bit in order to save time going forward.. 

The enclosures that were designed the week before arrived from 3DHubs, so all of the wiring was painstakingly untangled, de-soldered in some cases, the components placed into their respective enclosures, and then re-wired and re-soldered. By some minor miracle, all the electronics worked as they did before the operation took place. A master wiring technician might scoff at the result, but I think that it is a huge improvement.

Without the cover plate:

And with the cover plate:

A ribbon extension cable is on order for the camera, so that it can properly reach from the outside of the boat to the interior of the box.

I had originally intended to build my own printed circuit board to replace the semi-reliable ADC board (the yellowish brown prototyping board in the top-left corner of the above 2 photos). And one morning I set out to do that, but quickly realized that it was going to take weeks. Surely there was something on the Internet already put together? There actually didn't seem to be very much that was suitable, but I did manage to find this: https://store.ncd.io/product/4-channel-i2c-0-20v-analog-to-digital-converter-with-i2c-interface/ It's only 16-bit vs. the 18-bit that I have now, but its sampling rate is 4 times faster, so by maintaining a running average of 4 samples in the software, I should get the equivalent of 18-bit precision. It also accepts a wider input voltage than what I have now, which should help to simplify some of the signal conditioning electronics.

Lastly, some good improvements were made in AMOS's software for holding a fixed heading while driving forward smoothly. The previous control software was usually able to make the boat move forward at a fixed heading, but it was not smooth, requiring the rapid on / off firing of the left and right thrusters to maintain direction, while sacrificing forward speed. The new control algorithm is smoother and faster, and still keeps the boat following a forward course through the water. It has only been tried in the pool so far, but I hope to have it out in the river soon.