Autonomous mini-tractor

Description

Tractors became useful on small farms in the 1940s-50s when they became small, maneuverable and powerful. Add a 3 point hitch and every farmer could gain from owning one.

This project aims to build a powerfulish autonomous tractor with a simple web platform. Eventually, I hope to make this a useful way to automate small scale farming. My dad has a few acres of fields that sit idle because there's no cost-effective way to exploit it.

Details

The mini-tractor is going to be about 2 1/2 feet long. It's going to need to be quite heavy to pull any useful loads or tools, so I'm building the frame out of pretty chunky steel. The first iteration will be 2WD and powered by a hoverboard's innards. Hoverboards can supposedly haul around a full grown adult, should be lots of power for a V1 if it doesn't explode in a ball of flame.

By far the riskiest part of this build is the deep learning component. Over the winter I built a web app that can use a mobile device's camera to look at a League of Legends game and predict where enemies are hiding ungank.com. It was a fun experiment and I'm going to use it as a basis for this mini-tractor project. I'd like to thank the folks at fast.ai for providing an awesome deep learning library and course.

All CAD files and code can be found in the linked github repo.

Project Logs

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It's ALIVE!!!
a man • 07/09/2020 at 00:43 • 0 comments

I whipped up a quick web server and the mini-tractor moves!
Speed Controllers & Pi Hookup
a man • 07/08/2020 at 01:54 • 0 comments

I finally received the new speed controllers. They're now wired up to the Pi through a quick resistor bridge I made to do the DAC conversion for the throttle.

From here on out the project will be mostly focused on coding the web server and training the deep learning algorithm.
Teardown Complete!
a man • 06/01/2020 at 00:13 • 0 comments

The teardown of the hoverboard is done! I laid out electronics and wheels to get an idea of what it'll look like.
Very Hacky Wheel Control
a man • 05/30/2020 at 22:53 • 0 comments

My kids finally got bored of the hoverboard and I've started tearing it down. I wasn't sure how to control the wheels, there are a few projects where folks use custom firmware. At this point I really don't want a solution that requires that much effort, and even down the road I'll probably just buy a proper ESC.

For now I decided to stick a relay board on the wheel's power lines and leave the current hardware/firmware intact. As long as the pcb is mounted at an angle the hoverboard will always try to send power to the wheels, which I can start/stop with the relays.
Welding and Articulation Test
a man • 05/09/2020 at 16:10 • 0 comments

I got the frame welded up and threw on some lawn mower wheels and threaded rod to test the double-articulation. I was afraid it might be too sloppy, but it's actually very solid and should ensure that the mini-tractor has good traction. The turn radius is super tight as well.

I should receive the hoverboard this week.
Cutting the frame steel
a man • 05/03/2020 at 18:51 • 0 comments

I scavenged some angle iron and tube and cut up the parts for the frame. The articulation moves the right way, I'm happy I didn't screw that up.

Unfortunately I'm waiting on an order of welding rods, coronavirus restrictions in these parts don't allow us to go to stores unless it's essential.

There's my old 1952 Fergy TEA-20 in the background, she still pulls out my firewood every spring and hauls a wagon around for rides. She's part of the first generation of tractors which replaced horses and runs great even after 68 years of hard work.