Hacker News

OpenMower – An open source lawn mower

2025-08-190:35609190github.com

Let's upgrade cheap off-the-shelf robotic mowers to modern, smart RTK GPS based lawn mowing robots! - ClemensElflein/OpenMower

Hello! With a background in software engineering, embedded programming, hardware design, and robotics, I'm on the lookout for new challenges. If you're in search of someone with my skills, let's team up and create something amazing! https://x-tech.online/





Join the Discord server for OpenMower discussion:

Warning

DISCLAIMER:

IF YOU ARE NOT 100% SURE WHAT YOU ARE DOING, PLEASE DON'T TRY THIS AT HOME! ASK IN DISCORD, IF YOU HAVE ANY QUESTIONS!

Important

This project is active!

This is the hardware repository, so it might seem that the project is inactive, since hardware is pretty stable by now. Most of the development work is done on the ROS code here: https://github.com/ClemensElflein/open_mower_ros


If you want to see a quick overview, you can check out this video:

Let's be honest: The current generation of robotic lawn mowers sucks. Basically all of these bots drive in a random direction until they hit the border of the lawn, rotate for a randomized duration and repeat. I think we can do better!

Therefore, we have disassembled the cheapest off-the-shelf robotic mower we could find (YardForce Classic 500) and were surprised that the hardware itself is actually quite decent:

  • Geared sensored brushless motors for the wheels
  • A sensored brushless motor for the mower motor itself
  • The whole construction seems robust, waterproof and all in all thought through
  • All components are connected using standard connectors, therefore upgrading the hardware is easily possible.

The bottom line is: The bot itself is surprisingly high quality and doesn't need to be changed at all. We just need some better software in there.

Here is a quick overview of this project's goals:

✔️ Autonomous Lawn Mowing: Obviously, the device should be able to mow the lawn automatically.

✔️ Good Safety: The device must be safe, e.g. emergency stop if lifted or crashed.

✔️ No Perimeter Wire Needed: We want to be flexible and support multiple mowing areas.

✔️ Low Cost: It should be cheaper than a mid range off-the-shelf product

✔️ Open: I want to share knowledge and enable others to build an OpenMower as well.

✔️ Nice to Look At: You should not be ashamed to have an OpenMower mowing your lawn.

✔️ Avoid Obstacles: The mower should detect obstacles and avoid them during mowing.

✔️ Rain Detection: The device should be able to detect bad weather conditions and pause mowing until they improve.

Open Mower App 1

Open Mower App 2

The basic mowing function finally works! As you can see in the video, map teaching and mowing work as expected. It even returns to the docking station automatically as soon as the battery gets low and continues once it's recharged.

At this point I can recommend that brave tech savvy users can build one for themselves! Since it's quite an expensive and complex project, please don't be shy and ask if you have any questions. I'm glad to help 🙂

By now we have a stable revision of the mainboard as well as two motor controllers to go with it. The xESC mini and the xESC 2040. I'm currently using the xESC mini for my builds and it works very well. The problem with this controller is, its parts are currently hard to source. That's why we created the xESC 2040 based on the RP2040 chip. This is the low-cost variant and its support is currently experimental.

The basic software is basically done; Our prototype works as intended (but is not able to avoid obstacles yet).

The software for the robot can be found in a separate repository: https://github.com/ClemensElflein/open_mower_ros

If you want to read how to get started building a robot for yourself, check the OpenMower Website. There you can find information on which parts to buy, how to install the software and so on. If you find anything missing, please join the Discord server and ask there. Also there's the OpenMower Wiki which is written by the community. It has some additional guides and information.

You can help by starting an OpenMower build of your own. This helps to validate the concept and helps to create useful documentation for new users.

Additionally, you can help by starring 🌟 and watching 👀 this repository, since it will help with visibility. You can also subscribe to my YouTube channel.

While disassembling the bot, I wondered about its mainboard: Instead of "YardForce" it read "GForce". After checking the internet for "GForce" robots, I found that that very similar looking robotic mowers are sold under the Herkules brand. Naturally I tried to dig deeper and actually found evidence that the mainboard is manufactured by some chinese company (SUMEC Hardware).

GForce Robot Mower Mainboard

It is therefore quite safe to assume that many robot mowers are basically the same device in a different case. This would be a huge win for the community, since this would mean that by making one of those robots smarter, we could upgrade lots of robots.

Therefore it might be a good idea to start a list of compatible devices. So if you have a cheap robotic lawn mower, you can check, if it was already disassembled in the list below. If it's not there, it would be nice of you to check, if it contains the same mainboard as ours and add your robot to the list with some some pictures / model numbers.

By now, some guys have disassembled their mowers and it doesn't look as good as I initially hoped. The GForce boards are basically just used by YardForce and some rebranded versions for the EU market. My exact hardware was only found in the mower I'm using (YardForce Classic 500) and in recently manufactured SA650 ECOs. The SA650 has a different chassis and we don't have a way of mounting the GPS antenna yet. Therefore at the moment, the only compatible mower is mine (the YardForce Classic 500).

If you want to have a look at the disassembled mowers, check the Google Docs here

This page only contains the basic overview of the project. To follow my current development state, check out my Blog.

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.

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

Feel free to use the design in your private/educational projects, but don't try to sell the design or products based on it without getting my consent first. The idea here is to share knowledge, not to enable others to simply sell my work. Thank you for understanding.


Read the original article

rickcarlino

Karma: 2800
...
 @Hacker__News
@hacker._news

Comments

  • By albertzeyer 2025-08-1914:035 reply

    > The current generation of robotic lawn mowers sucks. Basically all of these bots drive in a random direction until they hit the border of the lawn, rotate for a randomized duration and repeat.

    I recently (a few weeks ago) bought one. While researching on the available options (which seemed relevant to me), actually almost none of the robots work this way. Most of them systematically go through the lawn. I think from those that I checked, only the Worx Landroid does it randomly.

    I was searching for some model which works without wires, because I was too lazy to set this up. Basically, in general, I wanted sth which required as little effort as possible.

    I decided for eufy E15, which uses camera (no GPS, no wires, no lidar, nothing else really). And it just seems to work. It creates a map first, and then systematically goes over the lawn. I didn't really need to do anything.

    (I'm not affiliated with eufy in any way. I'm just quite happy with it so far.)

    That said, obviously, having an open source variant of such a robot would be even nicer (if it works)! So I'm quite happy to see such a project.

    This robot here uses GPS, as far as I can see, as the sole technique for navigation and localization. From reports that I have read, GPS mostly works fine, except for some cases where it does not (where GPS coverage is not great). Camera on the other side always works (during daytime). Maybe this could be added to this project? Of course, using the camera is probably quite a bit more complicated, and more prone to errors, but overall might be more robust and reliable.

    • By mrbonner 2025-08-1916:50

      I have a Husqvarna and wouldn't be happier. It also randomly mows the lawn. I haven't paid a landscaper service forb3 years now. The only yard work I would need to care for are edge and bush trim. I have mostly flat yard with the size of 5000 sqft.

    • By k7sune 2025-08-1914:564 reply

      Wouldn’t it be kidnapped easily if it doesn’t use wires or GPS?

      • By JoeAltmaier 2025-08-1914:593 reply

        I often wonder about this.

        I think GPS is essential. Tie it to a location - if stolen, it won't operate. Then a way to text you if it is moved outside the designated area. Telling you where it is.

        At that point, I suppose it would still be worth stealing just for the battery? A hard problem to solve.

        • By bluGill 2025-08-1918:051 reply

          The problem with gps is it doesn't work (reliably) under trees which many lawns have. Since trees are common in yards they need something else anyway and at that point you can get rid of the gps

          • By typpilol 2025-08-1922:261 reply

            Need to get the multi-gnss like my cycling computer from Garmin has

            It's so accurate it's scary. Shows me the what side of the road I'm on and even shows me how much I'm in the lane lol

            • By bluGill 2025-08-1923:38

              that doesn't help when there is no signal which happens. Sometimes you can use other input to get more accurate, but only sometimes

        • By 0x457 2025-08-1918:59

          > if stolen, it won't operate.

          I can assure you it won't have level of protection like say iPhone, there will be a factory reset button in the mower.

        • By Kirby64 2025-08-2016:54

          Not super helpful if it doesn't have a way to communicate to the outside world. Some of the companies solve this by adding a cell module that can send an SOS, but it usually requires a monthly/yearly fee to maintain the cell connection.

      • By albertzeyer 2025-08-1916:09

        In my case, my lawn isn't easily accessible and also not visible from the street (because the house and garage is between the street and the garden), and I trust my neighbors. So, I think (I hope) this isn't so much an issue for my case.

        I think the eufy has also an optional GPS module just for this purpose, to better track it. I don't think this GPS module has any other purpose (e.g. it would not be used for navigation). But I didn't really checked the details on this.

        I have seen this a few times for such robots, that you can buy an optional GPS module for tracking.

      • By joshmarlow 2025-08-1914:58

        The sudden desire to add a small LLM and speech synthesizer so the mower can yell for help in a stranger danger scenario.

      • By jiehong 2025-08-1915:10

        Third law of robotics: self protect!

    • By goda90 2025-08-1914:171 reply

      Maybe instead of GPS or camera, it could have a local positioning system instead. 3 small, solar powered beacons can be installed around the yard to be mowed.

      • By albertzeyer 2025-08-1916:18

        I have seen such variants as well, where you actually need to install some antennas (RTK antennas?).

        But that was already too much effort for me, so that's why I chose the eufy. Also, from reports that I have read, it doesn't necessarily work better with antennas. Actually, from reports that I have read, robots with camera-only had the least amount of reports where navigation was not properly working. At least that was my impression.

    • By aidenn0 2025-08-2015:321 reply

      This doesn't use GPS directly, as that would have insufficient accuracy. It uses RTK, which calculates relative position from a base station very accurately.

      • By Kirby64 2025-08-2114:59

        RTK GPS still struggles underneath heavy foliage. You still need a GPS signal. The OpenMower project has an accelerometer in it for dead reckoning, but it needs to get back to a GPS lock pretty quickly or it'll lose positional accuracy quite quickly.

    • By codegeek 2025-08-1915:431 reply

      How large is your lawn and is it mostly flat ? I want to try one for my lawn but I have very large lawn and one side is slopy/steep.

      • By albertzeyer 2025-08-1916:15

        Maybe 300 m^2 or so.

        The eufy E15 is for up to 800 m^2. There is the eufy E18 for up to 1200 m^2.

        I have seen other (more expensive, bigger) robots for much larger lawns.

        My garden is relatively flat with a few bumps here and there.

        You can also easily mark some areas of the lawn as always excluded so that it wont drive there.

  • By boomskats 2025-08-199:243 reply

    So is this like Valetudo[0] but for mowers? Very cool! I wonder how much overlap / shared code there is between robot vacuums and robot mowers.

    [0]: https://valetudo.cloud/

  • By micheljansen 2025-08-1913:493 reply

    "Let's be honest: The current generation of robotic lawn mowers sucks. Basically all of these bots drive in a random direction until they hit the border of the lawn, rotate for a randomized duration and repeat. I think we can do better!"

    The funny thing is: this actually works incredibly well. Perimeter wires are a PITA to install, but once that's done, they are a very practical and flawless method for making sure the robot does not escape into the neighbour's yard or worse. The random movement is really effective too. What exactly can a smart robot do better?

    Removing the need for perimeter wires would be great, as long as it works 100% flawlessly. Obstacle detection would also be nice, so I can avoid my mower chewing up the toys my kid sometimes leaves lying around (though it is a great motivation to clean up!)

    • By razemio 2025-08-1914:081 reply

      I have a Mammotion Yuba and trust me, the grass looks awesome as a grid or in lines. It can even do logos. So far nicer looking grass and much faster then random.

      • By ai-christianson 2025-08-1915:36

        I have a mix of older automowers (e.g. 315x) and newer bots like navimow x330.

        The navimow does "mini stripes" and they do look nice, but the grass tends to look a little more "carpet" like with the automower randomized pattern.

    • By zamadatix 2025-08-1914:09

      It looks like obstacle avoidance is the key thing remaining in the software todos. For positioning it seems you get your pick of RTK GPS sensors, so it'd be interesting to still support guide wires for "escape protection".

    • By foobarian 2025-08-1914:08

      Regardless of how good the perimeter wire bots are, it's also not true that the more advanced generation "sucks." I have one and it works perfectly fine (Mammotion Luba 2). The hardware is great, positioning is great; there is always stuff to nitpick on the software side but at the end of the day that's great as well.

HackerNews

About