OpenMower v1 Documentation – Knowledge Base

Docs: Compatible Mowers

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

The project got started on a YardForce Classic 500(B) and there are (photo) guides at this documentation on how to dissassemble and assemble it again.
So the YF Classics 500(B) is from a users perspective the “best supported” mower.

The YF SA650ECO is the second model officially supported but there are no model specific guides yet.

Howerver there are more Mowers from the YardForce brand 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+ have compatible electronics to replace the stock mainboard by 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.

Confirmed convertable mowers

YardForce
- Classic
  - 500, 500B
- SA
  - 650ECO, 900ECO

Docs: Configuring xESC

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

If you bought the kit the xESC are preconfigured with VESC firmware 5.x"

device	xESC
/dev/ttyAMA2	drive motor
/dev/ttyAMA3	mow motor
/dev/ttyAMA4	drive motor

the config of the mow motor differs from the config of the drive motors, the configs of the two drive motors are equal

Configurations for each xESC can be found at https://github.com/ClemensElflein/OpenMower/tree/main/configs/xESC

Configuring the xESC

Prereqs:

VESC Tool (https://vesc-project.com/vesc_tool)

Connecting to the xESC:

sudo systemctl stop openmower
socat tcp-listen:65102,reuseaddr,fork file:/dev/ttyAMAx,raw <- replace x with devicenumber
start VESC Tool
Go to Connection -> TCP and insert openmower IP, leave port at 65102
Connect

To change xESC just Ctrl + C in the openmower terminal replacing ttyAMAx with a new device number and reconnect in VESC Tool.

Loading XML motor configuration:

Download XML configuration files from repo
File>Load Motor Configuration XML
Select file named motor for the xESC you connected to
On the right toolbar click “Write Motor configuration” (the M with a arrow pointing down)

Loading XML app configuration:

Download XML configuration files from repo
File>Load App Configuration XML
Select file named app for the xESC you connected to
On the right toolbar click “Write App configuration” (the A with a arrow pointing down)

Finally hit Ctrl + C in the openmower terminal and start the openmower service again. sudo systemctl start openmower

Docs: Firmware Update

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

Prerequisites

This update guide assumes that you have the following:

A mower with the OpenMowerOS running on it.
Important: verified that the /boot/openmower/mower_config.txt file has the correct hardware version set (OM_HARDWARE_VERSION). If this is wrong, the wrong firmware will be installed on your device. Check the Manual Firmware Installation guide on how to find that value.
The Raspberry Pi is running, and you are able to connect to it via ssh
The mower is connected to the internet

Step 1: Run the Firmware Update Script

The OpenMowerOS image contains a firmware update script which will download and install the latest firmware version for you.

In order to run the script, execute the following commands:

# Make sure that you are in your home directory (the script is located there):
cd ~/
# Execute the script:
~/fetch_and_upload_firmware.sh

If everything works as expected, the output should look like this:

Step 2: Done 🎉

That’s everything you need to do.

Docs: GPS / Coordinate System

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

Positioning / Coordinate System

Positioning in the Open Mower project is done in a local 2D coordinate system. This means that the robot’s current position can be described by the coordinates (X / Y) of the VRP and the current orientation.

The origin of the coordinate system can either be chosen freely by the user or can be set to the base station. If an external correction service is used, the origin has to be specified manually.

Open Mower uses a right-handed ENU coordinate system.

Docs: GPS Base Setup

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

This part of the documentation is work in progress. There are many ways of setting up the RTK base, here is one using RPi 0W, ZED-F9P and a web based software RTKBase. On discord you may ask karl.ranseier for support.

Prerequisites

Raspberry Pi 0W
µSD card
Power supply for RPi
Ardusimple ZED-F9P
A cable or combinatin of cables to connect micro usb male to micro usb male:
- A) Direct like this
- B) Adapter (like this) + micro usb to usb-a cable
A windows PC
Stable internet connection (no disconnection within one hour)

Installation

If you know about RPi and have already a functional OS, you may head on to “Software”, but in my case it did not work using an older image.

Preparing sd card

Download RPi Imager for windows
Start Imager:
Choose your RPI (in my case RPi 0W, choosing wrong RPi will most probably result in many problems)
Choose Operating system “Raspberry Pi OS Lite (32-bit)”
Select your sd card:
Press next so this will appear:
Edit settings like the following (and use your personal WiFi settings and country), where you set a good password for your Pi account. Username and password are case sensitive!
activate SSH:
Press save to see this:
Click on YES and allow to overwrite the data on your sd card (if you are sure, that you will not miss them). It will start downloading and writing the data:
Wait until it is finished, it may take half an hour, depending on your internet connection ;-)

Start your RTKBase RPi

Put your sd card into your RPi
Connect ZED-F9P via usb to your RPi (NOT after the installation, it will be configured during installation).
Power your RPi

Connect to RPi

Get from your router the IP of your RPi
Start PuTTY and connect to RPi, where you enter the local IP of your RPi
Enter your Username Pi, press enter and than enter your password:

Software

Is your ZED-F9P connected? Do it!
We will use RTKBase
To install it, you can use the following lines, which you can copy and paste at once. The original recommendation is no sudo in front of chmod. That did not work for me.
```
cd ~
wget https://raw.githubusercontent.com/Stefal/rtkbase/master/tools/install.sh -O install.sh
sudo chmod +x install.sh
sudo ./install.sh --all release
```

A very long output should follow. It ends with:

GNSS Configuration: done
################################
STARTING SERVICES
################################
Created symlink /etc/systemd/system/multi-user.target.wants/str2str_tcp.service → /etc/systemd/system/str2str_tcp.service.
Job for gpsd.service failed because the control process exited with error code.
See "systemctl status gpsd.service" and "journalctl -xe" for details.
################################
END OF INSTALLATION
You can open your browser to http://192.168.178.34 (here the editor deleted IPV6)
################################
Pi@RTKBase:~ $

Installation finished, go on and configure your RTKBase

Configuring your RTKBase

Start a browser and enter the IP address of your RTKBase. You will get this:
Enter as password admin. On the following site press the copy symbol right to PPP.
Go to settings and press “options” right to “Main Service”, than paste your coordinates to “Base coordinates”:
Press on options again, than on options right to “Caster Service”
Here you have to enter the setting set up in your mower, standard is: username gps and password gps. Select the right mount point. I have named it like my city, in mower config and here.
Save the config
Switch on “Caster Service” and “File Service”, it should look like this:
Eventually change your password below these options.
At logs you should find at least two files:

Find the position of your RTKBase

There are several ways to find your position. To use openmower you do not need the perfect position. Therefore the first option should be your choice, if you want a fast and good result for openmower.

Easy and good way

Click on the symbol right to PPP to copy the values to the clipboard:
Enter these values to your options at MainService.
Save
ReActivate Ntrip Service
Finished!

More complicated and more exact way

You have to set up the logging of your position as mentioned above by activating “file service”. You should wait for a day to average all the values to get a high precision position.
After midnight you find a zip-file at logs. This you can convert to a Rinex file. To understand this file you may check RINEX-File , but you don’t need it.
Press on the pencil right to the zip-file:
“Create Rinex file”:
Download it when finished (may take a while, some minutes or longer)
Go to Calculator, upload your Rinex file and enter your email address. Don’t forget to enter the “no robot”-verification.
When you received the email, look at “ITRF2014” (or search for “longitude”) and see your values like LONGITUDE 6.XXXXXXXXX° LATITUDE 51.XXXXXXXXX° HELL 79.9041
You enter these values to your options at MainService. Be aware that the order of LONGITUDE and LATITUDE is switched!
Save
ReActivate Ntrip Service
Finished!

Thanks to Stefal and all the contributors of RTKBase and the used resources.

Docs: Manual Firmware Installation

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

Info

You only need to do this if there is no firmware in your mainboard yet. If you have the mower already running or have received the hardware kit, you should be able to automatically update the firmware.
Check the guide here: Firmware Update

In order for ROS to talk to your mainboard, it needs to be programmed with a Firmware. Don’t worry, the process is straightforward.

Warning

It’s very important that you get the correct firmware for your hardware version. Using the wrong firmware will cause the device to malfunction and in the worst case, destroy the hardware.

Step 1: Download the Latest Firmware Bundle

The first step is to download and extract the latest firmware bundle. The zip file contains all the firmwares supported by the OpenMower project. You can get the latest version here: 🔗 https://github.com/ClemensElflein/OpenMower/releases

Step 2: Find the Firmware

In order to find the correct firmware file, you will need two pieces of information:

2.1: The hardware version of your mainboard

The version of your mainboard is printed on the lower left side of your mainboard:

2.2: The type of IMU you are using:

IMU Name	Image
WT901
MPU9250
LSM6DSO

3.3: Select Firmware:

Now you can select the firmware according to this table:

Mainboard Version	IMU	Firmware File	Notes
0.13.x	LSM6DSO	0_13_X/firmware.uf2	If you have bought the 0.13.x kit in Vermut’s shop, this is your version.
0.12.x	LSM6DSO	0_12_X/firmware.uf2	If you have bought the 0.12.x kit in Vermut’s shop, this is your version.
0.11.x	MPU9250	0_11_X_MPU9250/firmware.uf2
0.11.x	WT901	0_11_X_WT901/firmware.uf2	If you have bought the 0.11.x kit in Vermut’s shop, this is your version.
0.10.x	MPU9250	0_10_X_MPU9250/firmware.uf2
0.10.x	WT901	0_10_X_WT901/firmware.uf2	If you have bought the 0.10.x kit in Vermut’s shop, this is your version.
0.9.x	MPU9250	0_9_X_MPU9250/firmware.uf2
0.9.x	WT901	0_9_X_WT901_INSTEAD_OF_SOUND/firmware.uf2	WT901 gets soldered instead of the sound module, since this mainboard does not have a WT901 header
0.9.x	WT901	0_9_X_WT901/firmware.uf2	IMU Connected on the MPU9250 Slot using SerialPIO

Step 3: Install Firmware

In order to not draw too much current from your computer’s USB port, make sure that no modules (Raspberry Pi, GPS, ESCs) are plugged into your mainboard. Then connect the Raspberry Pi Pico with a micro USB cable to your PC.

Your PC should show a new mass-storage device. Copy the UF2 file identified above onto the mass-storage and wait for the Pico to reboot. The process takes about 10 seconds.

Step 4: Done 🎉

Your mainboard now has the latest firmware and is good to go. You can plug all modules into the mainboard now.

Docs: Neopixel LED Colors

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

Color	Meaning
boot sequence
dim red	firmware booted
bright red	RPi powered on
blinking blue	halt, IMU not found
turquoise (blue+green)	starting sound initialization
blue	setting sound volume
brown (red+green)	sound volume is set
blinking blue	warning, sound not available
end of boot sequence
orange - red flashing	emergency mode and ros is disconnected
green - red flashing	emergency mode and ros is connected
steady green	ros is connected and no emergency mode is detected (all voltages are OK, wheels aren’t lifted, emergency button is not pressed)

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!

Build Notes

Review Getting Started before ordering or installing parts.

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
OpenMower v1 Hardware Kit	The electronics mounted inside the robot and the charging station. Also includes the small parts that make the documented build easier.	1	Gadgets by Vermut shop	The shop kit is assembled, tested, and flashed before shipping.
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 4	The brain of the robot. RAM: 2GB+ for running the software 4GB+ for development	1	RPi Locator	Yes, it has to be the Raspberry Pi 4, because we need all the UARTs.
µSD Card	The absolute minimum capacity you should buy is 16GB. But better buy a 32GB one	1	Amazon* or your local hardware store	A Gucci option would be a RasPiKey
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: The Map

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

The Map

The most important information for the Open Mower is its map. The map tells the robot in which areas the robot is allowed to drive (= Navigation Area), which areas need to be mowed (= Mowing Area) and where the docking station is located. Using this information, the robot is able to do its work automatically.

Each area consists of one outline and multiple obstacles. The mower is allowed to drive inside the outline of all areas, except for the obstacles. This way you can exclude some parts of your lawn and prevent the mower from entering them.

The map is stored in the map.bag file that is located on the mower at /root/ros_home/.ros