OpenMower-V2 Carrierboard for SABO Mowers

Information

This hardware version is in beta state. Expect for things to not work at the current state!

About This Repo

OpenMower is an open-source project that upgrades off-the-shelf robotic mowers into modern, smart lawn mowing robots with RTK GPS technology. For more details, check out the OpenMower project.

This repository contains the design files for a custom carrierboard specifically designed for converting SABO based mowers to OpenMower V2.

For further infos or questions, please visit Discord

List of Compatible Mowers

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 (v0.1)	Series-II Carrierboard (v0.2)
Series-I (v0.1) @ John Deere Tango E5	Series-II (v0.2) @ Sabo MOWiT 500F

Required Additional Components

To build a complete OpenMower-V2 system, you will need the following additional components beyond the Carrierboard:

Essential Components

• 1 * xCore: OpenMower-V2 Development Board for all Low-Level processing
• 1 * Raspberry Pi CM4: System on Module (SoM) for all High-Level processing, >= 4GB RAM
• 3 * xESC mini: Electronic Speed Controller for BLDC motor
• 1 * WT-RTK-960: RTK GPS Module for precise positioning
• 1 * HA/HX-901: GPS Helix Antenna or similar

Optional Components

• MicroSD Card: High-quality MicroSD-Card (32GB+) for OpenMower-OS if CM4 is without eMCC
• RTK Base Station: If you've no public NTRIP service at your location

Usage

Meaning of the LEDs

LED	Meaning
Auto	Mow whenever possible (TODO), Semi- Auto (Mow entire map once and then wait for manual start again) (TODO)
Driving/Mowing	In autonomous mowing or driving mode (TODO), Area recording mode (TODO)
House/Home	GPS has RTK-Fix (TODO), Waiting for RTK-Fix (TODO)
Start/Play	Emergency, Waiting for ROS (TODO) Docked & charging finished, Docked & charging, Docked but no or faulty battery

Meaning of the Buttons

Button	Series-I	Series-II	Meaning
Auto	❌	✅
Driving/Mowing	❌	✅
House/Home	❌	✅
Select (left)	✅	❌
Start/Play	✅	✅	Start or Pause mowing (TODO)

Roadmap

• Hardware
  • Power/Dock
  • Networking
  • Charger
  • ESCs (BLDC Motors)
  • Emergency sensors (Front Wheel Lifts, Top-Stop, Handle-Stop)
  • Battery signal. CAN?
  • CoverUI (Series-I)
    • Buttons
    • LEDs
    • LCD Backlight
    • LC-Display
  • CoverUI (Series-II)
    • Buttons
    • LEDs
    • LCD Backlight
    • LC-Display
• Software
  • Firmware
    • Emergency (Series-I)
    • Emergency (Series-II)
    • Buttons
    • LEDs
    • LC-Display Driver
    • LC-Display GUI
  • ROS/OpenMower
    • Drive PIDs. At the moment the mower drive somehow stutter (not a big deal, but time consuming)
    • Limit blade motor to only one direction
    • Buttons 🔥
    • LEDs 🔥

Known Issues ‼️

• LC-Display is not working at all and it's doubtful if it ever will be (mainly due to missing technical specs like display controller, ...)
• Series-I CoverUI isn't connected (except LCD backlight) due to missing pinning (need a faulty Series-I CoverUI to reverse engineer the pinning). Since hardware v0.2, Series-I CoverUI is also connected.
• Series-II is only prepared for now, but not yet tested in any way

Additional Information

This Carrierboard includes more features than actually required to build an OpenMower robot. Additional features include a gigabit Ethernet switch, LiPo charger, and a 12V auxiliary power supply for extensions.

History

Carrier versions

Version	Date	Info
v0.2	2025/06	- Fix Series-II emergency osczillation issues - Support Series-I LEDs and Buttons - Support LCD
v0.1	2025/03	Initial Prototype

Patents, Local Laws, Liability

Before building a robot based on the designs published here, please make sure that you are allowed to do so in your specific regions. There may be patents and / or laws prohibiting you of doing so.

The code/schematics/PCB files are distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

This basically means: I'm just documenting a project of mine here for free and I don't have the time and resources to check that devices built using this information will be safe to use, legal to use or even work as intended. You will need technical know-how to use this project and I'm not liable for any damages your devices do to anyone or anything.

The RoHS mark on the PCB indicates presumed compliance based on supplier declarations. No third-party testing or certification has been conducted.

License

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.