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Raspberry Pi Automates Sustainable Farming

Twisted Fields' Acorn robot
(Image credit: Twisted Fields)

We love it when somebody builds a robot to automate a difficult task, or throw a golf club at your head, so this incredible project to create an agricultural robot that can benefit humanity as a whole really presses our buttons. Especially as there's a Raspberry Pi involved. Thanks to Hackaday for bringing this fantastic robot to our attention.

The ‘bot, known as Acorn, is the pride and joy of Twisted Fields, a 127-acre research farm in San Gregorio, California. Its fecund pastures are dedicated to the advancement of automation in agriculture so humanity can farm sustainably while still meeting the demands placed upon agriculture by a hungry population. They don’t use pesticides or GMOs, but they do use solar panels and SBCs.

Acorn has been around for a while, but recently received some interesting upgrades. The first is an emergency braking system that shorts out the geared hub propulsion motors in an emergency, bringing it quickly to a standstill. Another is a new navigation system that can follow custom complex routes, and a third is a simulation mode, so the robot’s software can be run inside a Docker container and tested, without using the robot itself.

The robot is open-source, so you can find all the software, as well as mechanical and electrical design files, on GitHub. It uses an 800W solar array to generate energy, which is then stored in a set of super-capacitors. The wheels come from a mountain bike, and each has a hub motor for four-wheel drive and steering. Farming tools and computer vision hardware are housed in the work envelope underneath the robot between the wheels. 

The brains behind Acorn are an Nvidia Jetson board to handle machine learning and automation, while the general operation of the bot is handled by a Raspberry Pi, which from the blue of its USB 3 ports looks to be a Raspberry Pi 4 This hangs on the back of a custom PCB that carries a voltage reducer, to turn the power generated by the solar panels into something the Pi can use. RS-485 signals via Ethernet cables allow the Pi to control the motors, which have been upgraded to hub motors from an earlier chain-drive system.

A future aim is for a farmer to tell Acorn what to do, and for the robot to figure out how to get there on its own. The upgrade to the GPS system helps facilitate this, as it can now be programmed to follow farm roads at high speed, before reaching rows of crops and slowly following them up and down while using any tools slung underneath it. It also provides telemetry that can reveal the contours of the land it’s traversing, making it easier to produce level rows which conserve water and reduce erosion.

All the software is available on GitHub, ready for Docker containerization and tinkering, while the farm’s YouTube channel contains footage of the robot at work, and also some cute goats.

Ian Evenden
Ian Evenden

Ian Evenden is a UK-based news writer for Tom’s Hardware US. He’ll write about anything, but stories about Raspberry Pi and DIY robots seem to find their way to him.