OpenMower — Open Source RTK GPS Robotic Mower – Getting Started

Docs: Compatible Mowers

Mon, 01 Jan 0001 00:00:00 +0000

Yard Force

Check out the Git Repo Here: https://github.com/xtech/hw-openmower-yardforce

The project got started on a YardForce Classic 500(B), and there are photo guides in this documentation on how to disassemble and reassemble it. From a user’s perspective, the YardForce Classic 500(B) is the “best supported” mower.

However, there are more mowers from the YardForce brand that are compatible:

In theory, every YardForce model with the Core + Outer Frame Chassis (SA, SC, LUV, N and NX Line) that has a production year of 2019+ has compatible electronics to replace the stock mainboard with an OpenMower one.

As of today the YardForce Amiro, Compact, EasyMow, MowBest, XPower and MB series models are not (yet) compatible.
The main reason is that the OpenMower mainboard does not fit in their chassis.

SABO / John Deere

There is a dedicated mainboard for SABO MOWit 500F (Series-I & II) and John Deere Tango E5 (Series-I & II) mowers.

Check out the Git Repo Here: https://github.com/xtech/hw-openmower-sabo

This Carrierboard is compatible with the following mower models:

SABO MOWit 500F (Series-I & II)
John Deere Tango E5 (Series-I & II)

Series-I Carrierboard (v0.2)	Series-II Carrierboard (v0.2)

Series-I (v0.1) @ John Deere Tango E5	Series-II (v0.1) @ Sabo MOWiT 500F

These mowers are well supported. Even the display controller was replaced by a fully functional, modern user interface!

Your browser does not support the video tag.

Universal Board

The universal board contains all features needed for an Open Mower build (e.g., three BLDC/DC motor controllers, a LiPo charger on board, connectors for GPS, emergency sensors, etc.). It has screw terminals for easy connections and can be broken into smaller modules if it doesn’t fit as a whole board.

Check out the Git Repo Here: https://github.com/xtech/hw-openmower-universal

Other Compatible Brands

The following mower brands are known to have compatible hardware with the Universal mainboard. If you want to check your specific model, ask on Discord. The probability is high that it will work:

Husqvarna: Most Husqvarna mowers
Gardena: Most Gardena mowers
Fuxtec / Redback: Fuxtec and Redback mowers

Custom Hardware

If you have a custom chassis, there is a good chance you can get it to work with the Universal board. Ask on Discord for guidance on your specific setup.

Docs: Shopping List

Mon, 01 Jan 0001 00:00:00 +0000

If you make a purchase through the links marked with an Asterisk (*), I may earn a small commission at no extra cost to you. Thank you for supporting this project!

Warning

Read this first: Important Info

Parts for the Robot and the Charging Station

Name	Description	Quantity Required	Source Link	Notes
Mower (YardForce Classic 500(B))	The mower to modify.	1	Amazon*	Check the Compatible Mowers
Open Mower Hardware Kit	The electronics we will mount inside the robot. Consists of the mainboard (includes LiPo charger), xCore board, and 3x ESC.	1	Contact @Apehaenger on Discord, he has Hardware available (see Announcement )	Alternatively you can source and solder most of these parts yourself. Check the repositories in the Links section for PCB designs and BOMs.
Ardusimple RTK2B GPS + Antenna	Positioning system for the robot	1	ArduSimple	Some users use UM9XX chips (available from WitMotion and AliExpress ) as alternative. Compared to ArduSimple, they’re a bit cheaper and support triple-band frequencies.
Raspberry Pi Compute Module 4 with WiFi	The brain of the robot. RAM: 2GB+ for running the software 4GB+ for development 16GB+ storage (eMMC or µSD Card)	1	RPi Locator	Must plug into the xCore board — CM4 and CM5 are supported. Other CM-compatible boards may work but the pre-made OS image won’t.
µSD Card	Only for RPi CM4 Lite. The absolute minimum capacity you should buy is 16GB. But better buy a 32GB one	1	Amazon* or your local hardware store
Optional:	Optional:
USB Wi-Fi Dongle	For better Wi-Fi reception	0		Check for Linux Support
Left-Angle USB adapter	If you want to keep Wi-Fi dongle inside the mower. RPi USB is really close to the mower side wall	0	Amazon* or your local hardware store	The kit contains the wire to connect external USB port. That may be enough if Wi-Fi dongle is waterproof.

Parts for the GPS Base Station

Info

You only need a GPS base station if you don’t have access to an external NTRIP service. There are multiple free services available, so check before buying this.

Name	Description	Quantity Required	Source Link	Notes
Raspberry Pi + SD Card + Power Supply	You can basically use any Raspberry Pi for this. No special requirements.	1	e.g. Raspberry Pi 4
Ardusimple RTK2B GPS + Antenna	Positioning system for the base station	1	ArduSimple	See above

For the setup check the GPS Base Setup Guide

Docs: System Architecture

Mon, 01 Jan 0001 00:00:00 +0000

OpenMower is split into distinct layers — each with a clear responsibility — connected by well-defined interfaces. This separation means you can work on navigation logic without touching firmware, or add a new robot platform without changing ROS.

Layers

App — User Interface

The OpenMower App runs on a phone or browser and lets the user control the mower, record areas, and monitor status. It communicates with ROS over MQTT on the local network via a dedicated ROS node that bridges MQTT messages to ROS topics.

The Raspberry Pi Compute Module 4 runs the full ROS navigation stack. This is where high-level decisions are made: where to drive, how to cover an area, when to dock. ROS receives sensor data (position, orientation, odometry) from the firmware and sends motion commands back.

ROS is deliberately decoupled from hardware — it never talks to motors or sensors directly.

xbot_framework — The Bridge

ROS and firmware communicate over Ethernet using xbot_framework — a message-passing middleware that decouples the two layers. This means the navigation stack does not need to know anything about the specific hardware platform.

Firmware — Motor Control & Sensors (xCore · STM32H723)

The firmware runs on the xCore board and owns all low-level hardware: driving the motors via xESC controllers, reading the GPS and IMU, managing the battery and charger, and enforcing safety states (the emergency service can cut power independently of ROS). The same firmware codebase supports multiple robot platforms through compile-time configuration.

RTK Base Station — Centimetre-Accurate Positioning

RTK GPS works by comparing signals between a rover (the GPS receiver on the mower) and a fixed base station at a known position. The base station sends RTCM correction data to the mower’s GPS receiver — via radio or over the internet (NTRIP) — reducing positioning error from metres to centimetres. The base station must be external and stationary; this is a fundamental requirement of RTK, not an OpenMower limitation.

Docs: Hardware Versions / Known Issues

Mon, 01 Jan 0001 00:00:00 +0000

Current Hardware (v2 Hardware Platform)

For v2 Hardware Platform, please check the corresponding repository for changes and known issues:

YardForce: https://github.com/xtech/hw-openmower-yardforce
SABO / John Deere: https://github.com/xtech/hw-openmower-sabo
Universal: https://github.com/xtech/hw-openmower-universal

Legacy Hardware (v1 Hardware Platform)

Information

V1 hardware used a completely different architecture to v2 hardware which makes it hard to port to new mower models. If you currently own a v1 hardware kit, this is nothing to worry, the kit will continue to work with your mower, there is no real benefit of upgrading it to a v2 hardware kit. For new builds, the v2 hardware platform is recommended.

0.13.0 - Red

Notable changes

Custom CoverUI added to the kit
Dropped support for dfPlayer sound module

Known issues

2.5mm screws were missing (used to fasten RPi4). Affect kits shipped before June'23.
The first batch of 0.13 boards was mistakenly labeled “latest”. No action needed.
Outdated Firmware . Affect kits shipped before May'23.
IC2 chip is wrong . Affect kits shipped before May'23.
rain sensor cable is female, but needs to be male . Affect kits shipped before May'23.

0.12.0 - Black

Notable changes

IMU: LSM6DSO instead of WT901

Known issues

SPI tracks from Pico were misplaced, already fixed in firmware. No action needed.
Outdated Firmware
IC2 chip is wrong
rain sensor cable is female, but needs to be male

0.11.0 - Purple

Notable changes

Connected WT901 via I2C freeing pins for dfPlayer
Upgraded dock station PCB with extra holes and terminals (red)

Known issues

IC2 chip is wrong

0.10.0 - Green

Notable changes

Added dock station PCB (green)

Known issues

IC2 chip is wrong

0.9.3 - Also Green

First build. Experimental xESC2040 instead of xESC-mini (STM32).

OpenMower — Open Source RTK GPS Robotic Mower – Getting Started

Docs: Compatible Mowers

Yard Force

SABO / John Deere

Universal Board

Other Compatible Brands

Custom Hardware

Docs: Shopping List

Warning

Parts for the Robot and the Charging Station

Parts for the GPS Base Station

Info

Docs: System Architecture

Layers

App — User Interface

ROS — Navigation & Planning (Raspberry Pi CM4)

xbot_framework — The Bridge

Firmware — Motor Control & Sensors (xCore · STM32H723)

RTK Base Station — Centimetre-Accurate Positioning

Docs: Hardware Versions / Known Issues

Table of Contents

Current Hardware (v2 Hardware Platform)

Legacy Hardware (v1 Hardware Platform)

Information

0.13.0 - Red

Notable changes

Known issues

0.12.0 - Black

Notable changes

Known issues

0.11.0 - Purple

Notable changes

Known issues

0.10.0 - Green

Notable changes

Known issues

0.9.3 - Also Green