TURN A CHEAP STORE LAWN MOWER INTO A SELF-DRIVING ROBOT WITH CENTIMETER GPS ACCURACY
Replace a cheap mower's electronics with a Raspberry Pi and RTK GPS — it mows autonomously with centimeter accuracy and no boundary wire.
GardenRobotics
Built withRaspberry Pi
- difficulty
- ●●●●○
- time
- a long weekend
- license
- CC BY-NC-SA 4.0
- repo
- repo ACTIVE6,720 stars
●●●●○ · a long weekend · CC BY-NC-SA 4.0 · 6,720 stars · repo ACTIVE
WHAT YOU’LL NEED
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COMPAREE VERDICT
OpenMower turns a cheap off-the-shelf robotic mower, the YardForce Classic 500 being the reference model, into an RTK-GPS-guided mowing robot. Instead of bouncing around randomly inside a boundary wire, it follows mowing areas you record in the app, with centimetre-level positioning when it has an RTK fix. The electronics are replaced with the project's own hardware: a mainboard with LiPo charger, an xCore board with a Raspberry Pi Compute Module, three xESC motor controllers and an RTK GPS receiver. You can buy the hardware kit through the community or source and solder the boards yourself. The docs put the conversion at around 700 euros, not counting the mower and an RTK base station, and a weekend of work for a YardForce-class mower. The catch: you need RTK corrections, from your own base station or an NTRIP service (some countries have free ones), and good sky view, because trees and buildings hurt reception. You also need to be comfortable with Linux, a Raspberry Pi and electronics. The licence on the design is non-commercial: no selling it or products based on it without the author's consent.
IN THE REPO
GOOD TO KNOW
- —Full ROS stack, mainboard firmware, PCB designs and a step-by-step guide are published across the project's linked repositories and openmower.de.
- —The design documentation is CC BY-NC-SA 4.0: private and educational use is fine, selling the design or products based on it needs the author's consent. Software repos are GPL or MIT.
- —You supply the base mower (YardForce Classic 500 or equivalent) — the project replaces everything inside it.
- —RTK GPS base station is required for centimeter accuracy; you can build one or subscribe to a correction service.
- —Active Discord community (2,000+ members) and regular updates.
- —A hardware kit (mainboard, xCore and three xESC boards) is available through the community on Discord; alternatively you can source and solder the boards yourself from the published PCB designs and BOMs.
Parts to buy
5 itemsFrom our check of the build. Exact quantities and part numbers are in the creator’s BOM.
Can I build this?
Build at your own risk. Projects involve tools, electronics and sometimes mains voltage — follow the creator’s safety notes.
Videos
OpenMower - The affordable Open Source DIY Smart GPS Robotic Mower
The creator's own overview video, linked from the README; the full step-by-step guide is on openmower.de.
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Start here
Navigation into the creator’s own docs — we don’t rewrite the guide, we route you to the source.
- 1.Read the compatibility page on the wiki to confirm your mower model is supported before buying anything. (YardForce Classic 500 is the reference model, but others work — check first.)
- 2.Get the OpenMower hardware kit, or build the boards yourself(The kit (mainboard, xCore, three xESC) is available via the community Discord; to build your own, use the PCB designs and BOMs in the xtech hardware repositories.)
- 3.Set up the RTK base station or sign up for an NTRIP correction service.(This is the step people skip and then spend a weekend debugging poor GPS accuracy.)
- 4.Follow the assembly guide in the wiki to gut the mower and install the new electronics.(Take photos as you disassemble — reassembly is easier with a reference.)
Resources
Documentation, files and community threads for this build — we link straight to the original sources and never rehost the creator’s files.
KNOWN ISSUES
- Buying a mower that is not on the compatibility list: check the Compatible Mowers page first; YardForce Classic 500(B), SABO and John Deere models have dedicated carrier boards, others need the universal board.
- Skipping the RTK base station setup and expecting GPS accuracy to work anyway — it will not, and the mower will wander.
- Underestimating the Linux side: the app simplifies configuration, but you may still need to debug over SSH and adjust settings by hand.
- Buying a plain GPS module: you need an RTK-capable receiver. The docs use the ArduSimple RTK2B; some users run cheaper UM9xx receivers instead. Ordinary GPS without an RTK fix is not enough for precise mowing.
- Skipping configuration: set up the xESC motor controllers and ROS parameters (including the GPS antenna offset) as described in the knowledge base, or paths will not line up with your recorded areas.
- Mounting the GPS antenna too low or under tree cover — even RTK needs a clear view of the sky, and signal dropouts under branches are the most common complaint.
Can I use a different mower brand?
Possibly. YardForce Classic 500(B) is the reference model; other YardForce SA models, SABO MOWit 500F and John Deere Tango E5 have dedicated carrier boards, and many other models work with the universal carrier board. Check the Compatible Mowers list before buying.
Do I need my own RTK base station or can I use a correction service?
Either works. Check first whether there is an NTRIP correction service near you (the troubleshooting guide assumes a node within about 30 km); some countries have free ones. If not, build a base station from any Raspberry Pi and a second RTK2B receiver.
What happens if GPS signal is lost?
Precise mowing depends on a continuous RTK fix and correction data. Trees and buildings can interfere with reception, so check your garden with the GPS troubleshooting guide before you commit.
Can I sell a finished mower or offer mowing as a service?
Not without permission. The design documentation is CC BY-NC-SA 4.0 and the README says not to sell the design or products based on it without the author's consent. Software repos are GPL or MIT, so check each one.
Community builds
No community builds yet — be the first, we feature the best ones.
Discussion1
FROM THE COMPAREE TEAM
RTK GPS is the unlock here — but it also means you need a base station or a subscription before the mower will hit centimeter accuracy. Did you go local base or NTRIP service, and what surprised you about the setup?
Clemens Elflein
Clemens Elflein started OpenMower by taking apart the cheapest robotic mower he could find, a YardForce Classic 500, and replacing its random-bounce brain with custom hardware and open-source software. It grew into a full platform with dedicated boards for several mower brands, documentation at openmower.de and an active Discord community.
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DISCLAIMER
- Comparee is not the author of the projects featured here. All rights to each project belong to its creator — every page links to the original source, and we never host creators’ files.
- Information is provided without warranty and may become outdated as projects evolve. Prices are indicative bands only — always check the creator’s parts list for current costs.
- Building and operating any project is at your own responsibility. Protective equipment, safe workshop practice and compliance with local regulations are the builder’s responsibility.
CompareeTEAM2mo agoedited
Practical notes from our verification: the repository is active and acts as the entry point — the actual code and hardware live in linked sub-repositories, and the full step-by-step build guide is at openmower.de. The README links an overview video by the creator and his YouTube channel, and the Discord (2,000+ members) is where builders get help. The docs put the hardware shopping list at around 700 euros, excluding the mower and the RTK base station. The single biggest trip-up is the RTK base station: people assume the GPS module alone is enough, but without RTK corrections, accuracy drops to meters instead of centimeters, and the mower's autonomous navigation falls apart. If you have never worked with ROS, budget extra time for the Linux setup and firmware flashing. Licences differ: the documentation in this repo is CC BY-NC-SA 4.0, while the software repos carry their own GPL or MIT licences. Correction (4 October 2026): we re-checked this page line by line against the project's own repository, documentation and videos, and fixed errors in earlier versions.