Hackaday Prize 2023: Computer Vision Guides This Farm Mower

It’s a problem common to small-scale mixed agriculture worldwide, that of small areas of grass and weeds that need mowing. If you have a couple of sheep and enough electric fence there’s one way to do it, otherwise, if you rely on machinery, there’s a lot of hefting and pushing a mower in your future. Help is at hand, though, thanks to [Yuta Suito], whose pylon-guided mower is a lightweight device that mows an area defined by a set of orange traffic cones. Simply set the cones around the edge of the plot, place the mower within them, and it does the rest.

At its heart is a computer vision system that detects the cones and estimates distance from them by their perceived size. It mows in a spiral pattern by decreasing the cone height at which it turns, thus covering the whole area set out. Inside is a Raspberry Pi doing the heavy lifting, and because it’s designed for farmland rather than lawns, it has an adaptive track system to deal with obstacles. In its native Japan there is an ageing rural population, so it is particularly suitable for being operated by an older person. See it in action in the video below the break.

A robotic mower aimed at farms is certainly unusual here, but we’ve seen a lot of more conventional lawnmowers.

Continue reading “Hackaday Prize 2023: Computer Vision Guides This Farm Mower”

OpenMower: Open Source Robotic Lawn Mower With RTK GPS

Robotic mowers are becoming a common sight in some places, enabled by the cost of motors and the needed control electronics being much lower, thanks to the pace of modern engineering. But, in many cases, they still appear to be really rather dumb, little more than a jacked up bump-and-go with a spinning blade. [Clemens Elflein] has taken a cheap, dumb mower and given it a brain transplant based around a Raspberry Pi 4 paired up with a Raspberry Pi Pico for the real time control side of things. [Clemens] is calling this OpenMower, with the motivation to create an open source robot mower controller with support for GPS navigation, using RTK for extra precision.

The donor robot was a YardForce Classic 500, and after inspection of the control PCB, it looks like many other robot mower models are likely to use the same controller and thus be compatible with the openmower platform. A custom mainboard houses the Pi 4 and Pico, an ArduSimple RTK GPS module (giving a reported navigational accuracy of 1 cm,) as well as three BLDC motor drivers for the wheels and rotor. Everything is based on modules, plugging into the mainboard, reducing the complexity of the project significantly. For a cheap mower platform, the Yardforce unit has a good build quality, with connectors everywhere, making OpenMower a plug and play solution. Even the user interface on top of the mower was usable, with a custom PCB below presenting some push buttons at the appropriate positions.

OpenMower mainboard

Motor control is courtesy of the xESC project, which provides FOC motor control for low cost, interfacing with the host controller via a serial link. This is worth looking into in its own right! On the software side of things, [Clemens] is using ROS, which implements the low level robot control, path planning (using code taken from Slic3r) as well a kinematics constraints for object avoidance. The video below, shows how simple the machine is to operate — just drive it around the perimeter of lawn with a handheld controller, and show it where obstacles such as trees are, and then set it going. The mower is even capable of mowing multiple lawns, making the journey between them automatically!

Robotic mower projects are not new around here, here’s the mysterious TK with an interesting take, another using RTK GPS for good (or possibly bad) and quite probably the jankiest one we’ve seen in a while, which uses a LoRa base-station to transmit RTK corrections. We’d recommend keeping well away from that last one.

Continue reading “OpenMower: Open Source Robotic Lawn Mower With RTK GPS”