Yet another Arduino autopilot for wheel or tiller ($150)

[JeffBurright]

Hello,
On the subject of Arduino autopilots, I humbly submit my own winter project creation. I built two pilots - one for wheel and one for tiller - based on my own code built from the "Jack Edwards autopilot".

My rendition uses an ESP32 as the brain, with a wifi/HTML interface so it can be controlled from any phone, including PID tuning and deadband adjustment from inside the interface. This is a dead simple compass-only pilot, like an ST2000 or similar, and I have tested it on an Islander 36 and a Northwest 21.

Total project cost is approximately $150 for each version. I included a parts list with links on my GitHub page here: https://github.com/jeff-burright/Autopilot_ESP32_wifi/tree/main.

The code is still subject to tweaks, but my code allows easy over-the-air updates so owner customization is easy.

Short video of the tiller version in action this weekend:

https://www.youtube.com/watch?v=wBYxuOjN69g

Video of the wheel version while I waggled the compass at the dock: https://www.youtube.com/shorts/7anuzTAU0g8

Pic of HTML interface: https://imgur.com/7R8gE5P.jpg

Some photos of the hardware on the two boats are attached. Note that the external battery was just for testing, and the version installed on the boat is tied to the 12V system. In addition to phone control, the big boat version has an LCD screen and a big red button stuffed into an old instrument round, an IR remote control, and a rudder feedback sensor to improve efficiency. Note that I changed the wheel motor box from what's pictured to have the whole box flip up on a hinge rather than using a tension pulley. The pulley didn't work as well as I'd hoped, but the hinge box works well so far.


Hooray for lowering the bar on marine autopilots!

Use at your own risk, no guarantees, yadda yadda.

[markxengineerin]

Awesome work, I especially like the clever enclosures- filing the pill bottle idea away for future use. Thanks for posting.

[JeffBurright]

Thank you, it was a labor of love for saving money. Not pictured is the compass chip I affixed to the cabin ceiling of the Islander inside a tic tac box.

[Ryban]

Sounds like a fun project!

What are you using for a digital compass and how is that being calibrated? I was messing with this a little for one of my own projects.

[Bill O]

Jeff,
Looked at Jack's Arduino AP many years ago and looks like you may have added some nice tweeks to make it work better. Good job.
My coding skills were not very good at that time (not much better now) and decided to go with pypilot instead. Are there any features on yours that would help advance the pypilot?

[JeffBurright]

Originally Posted by Ryban

Sounds like a fun project!

What are you using for a digital compass and how is that being calibrated? I was messing with this a little for one of my own projects.

This one uses an older LSM303/L3G 9-axis compass chip like this: https://www.ebay.com/itm/202091223251

I did an initial calibration using a small Arduino sketch that reports the xyz min/max by waving the chip around, and those values are coded into the base sketch. There is also a magnetic variation variable that you can set in the base code and then modify within the HTML interface depending on your latitude. Adjusting the mag var variable can also make up for an imperfect forward-facing installation of the compass chip (ask me how I know). Jack's original code also has a drift correction algorithm that I don't 100% understand, so I just kept it.

So far I found that the pilot keeps course well on our lake, but I wonder what specific problems you were seeing with your compass. Was it a drift issue over longer heading fixes, or something else?

----

To Bill's question, I think the pypilot has more technical features (like GPS and wind tracking) and hooks into other services like openCPN. I'm just an amateur in the coding realm, and Arduino/C made more cognitive sense to me than python for some reason. I actually removed the GPS and wind functions from Jack's original code because they didn't fit my simplicity approach (and I cruised with an ST2000 before and found it to be entirely adequate for my kind of sailing). Plus, it seemed Raspberry Pis were more expensive and hard to find, so I opted for the $10 ESP32.

Personally I prefer my own user interface, and for me there is value in having an independent system where every component is super cheap, easily swappable, and simple to assemble. I might be reinventing a wheel here, but there is some pleasure in 'rolling your own'.

[Lake-Effect]

Great project! Thanks for sharing.

[mgrouch]

You do not need to hardcode magnetic variation.
You can simply integrate this
library into your code:

https://github.com/DavidArmstrong/WMM_Tinier

Thanks!