I am looking into GNSS modules at the moment. You have some great information here.
How do you find the performance of the ZED-F9P compared to the ComNav K501g or K706? Especially accuracy and performance in conditions with multi-path reflections. Can you rely on the accuracy estimate given by the ZED-F9P module?

Hi Geo — The u-blox L1/L2 antenna with a 10cm metal ground plane should perform quite well. I’ve used several “cheap” antennas (i.e. TopGNSS) with the ZED and they work well. Of course Harxon antennas are great.

If you’re not getting an RTK Fix then something is wrong. I’d say splurge for your own ZED-F9P base station and see if that turns out to be the magic sauce.

Take care,

Roby

Hi James — If you’re under a solid covering of dense trees you might notice it jumping out to Float — that said it’s performance in obstructed environments is remarkable, IMO.

Take care,

Roby

Hi David,

I’m glad that you’re following your passion! Years ago I got a Software Engineering degree, but honestly never was all that excited about software ’till I got into robotics and started writing software for these robots. So, the more you dabble in robotics, the slick thing will be that your ME background will give you insights into that part of robotics that simply aren’t obvious to the rest of us who didn’t spend that much time learning ME.

Now, to your question about the size of the Honda disk — you’re looking at approximately 11.1 cm diameter from the center of the disk to the end of the blade.

Here’s a pic:

Glad to hear from you and look forward to hearing about your progress.

Take care,

Roby

Thank you so much for making this blog and youtube videos. I will be a recent grad in Mechanical Engineering but do not feel fulfilled with only learning this field of engineering, so I am diving into a project utilizing computer engineering skills. Your information here has taught me so much and I am very grateful.

I am currently making my own revision to your Rover 2. I really liked that you utilized the rotating disc with centrifugal blades. I am making a model in Fusion360 and attempting to make a layout before I start fabrication. I cannot find the part dimensions for the mower disc.

Do you know a rough estimate for the OD of the disk?

Thank you!

Hi Robert,

The Pi serves as a general-purpose onboard computer I can log into while the robot is running around the yard.

For this build, I think the only actual function of the Pi is this: we connected one of the Pixhawk telemetry ports to the Pi (via that UART-to-USB connector you see plugged into one of the Pi’s USB sockets) and them we run MAVProxy to forward that telemetry info (as UDP) to a port on our network. If you’re familiar with Mission Planner, you can then connect to this telemetry stream by specifying whatever port # you’re sending the data to.

Another thing is that the Pi’s camera is slick and cheap — so you’ll notice the GoPro camera case mounted on the middle shelf of the structure — there’s just a Pi camera in there that we hot-glued in. So if I’m in the living room and I want to see the FPV of the robot, then I can hit the Pi’s camera stream.

Note that the Pi’s ethernet is connected to the Ubiquiti Unifi router’s ethernet port — I like using the Ubiquiti network connection (instead of the Pi’s onboard wifi radio) because it’s much more robust.

One other thing, just to be clear — when the robot is running around, you can connect to the Pi either by ssh (the Pi is on the local network via the Ubiquiti connection), or via VNC (I use a Mac and VNC Viewer which performs quite nicely).

Hopefully that info helps out a little 🙂

Take care,

Roby

What does the PI do and what is it connected to?

Hi Robert — You are correct, the Scag automower post is updated per your guidance.

Take care,

Roby