Need Help: Automated Reel / Winch

Hello! I own a small business building unmanned boats and an opportunity has arisen to use these to raise/lower a water quality monitoring sonde; I need to find or build a reel system to facilitate this. The sonde communicates via an RS485 interface, so this will need a slip ring of some sort. I’ve been all over the place on my thinking, but my thinking now is as follows:

  • Probably based on some type of ardunio, teensy or SBC type controller, with encoder, and brushed motor controller which ahs current sensing feedback.
  • Controlled via PWM signals, so it can connect to the autopilot in the boat without a lot of dev effort. I am thinking something like pwm 1000us = fully retracted, 2000us = fully deployed; the specific amount length metered out being defined later; but probably no more than 100ft, and likely closer to 50. This PWM method would allow me to get a proof of concept out being tested fast, as I can just set the servo output to a whatever I want on that channel, script it in a mission or use a lua script. Later, a WebUI could be setup to allow more user-friendly control, but for now; whatever. I need to get something going ASAP.
  • I am not sure I can afford to reinvent the wheel so perhaps buy something like ths:Reel 200/300ft 5000psi Electric 12v Cox (68-102): Cox Reels | J. Racenstein Company, LLC – controlled with the brushed motor controller and with the cable going through a pully with encoder. It it gets stuck or upon being fully retracted, it can stop based on a current spike OR perhaps some type of stop switch or both.
  • Need to add a slip ring or terminate the connection to a small device (which receives and retransmits wirelessly) on the rotating portion of the reel. A 2-wire slip ring to power that might be easier than one for the RS485 cable; or it could even be battery powered for now, or maybe adding a slip ring is easy?

These are just the rantings of a nerd redneck, so I’m not above someone saying “that’s a stupid way to approach this” and correcting my ignorance. Whatever path is taken, I need to find someone to help setup the controller portion of this, so please let me know if interested!

Here is the boat I built for this, though I usually use it for bathymetry. I can weld up a different mid-section as needed to accommodate whatever we come up with.