Introduction: Build a Robot Lawnmower
Here are the components used in this build. This project relies on electric wheelchair motors, I used pride mobility motors in this tutorial. However, I have used jazzy chair motors on a past project. You can find these motors and gearboxes for a reasonable price, used, on ebay. Links provided in this tutorial are affiliate links, and help to support future projects like this one.
Step 1: Get Your Lawnmower
When choosing the lawnmower for this project, try to avoid the new ones that have plastic where the wheels mount up. You want to choose an all-metal lawnmower so it will last. I use these
Step 2: Motor Controller
The key to making these wheelchair motors work is the motor controller. You want a dual controller to run each motor independently. It also has to be capable of handling the amps, I used this controller for this project
On my previous build, I used a different controller. It is a good option as well but will require adjustments to the DIP switches for your needs. Also, it does not come with 3 pin hobby wires that are needed for this project. It's still a great controller though, you can get it here
Step 3: Transmitter & Receiver
You can use a typical RC hobby controller for this, and there are a lot of options out there. You will only use two channels but it is good to have extra channels for things you might want to add later. I used this 10 channel.
Step 4: Batteries
These motors can be run at 12v or 24v. I have done it both ways and a single 12v battery will suffice for the average yard. However, two batteries at 24v will give you more power and speed. These can be wired in series or parallel to achieve your particular needs.
I recommend your batteries be between 18-22 amp hour. I used these 22 AH batteries
Step 5: Mounting Your Motors
Remove your back wheels and remove the handle from your lawnmower and line up the gearbox holes with the holes left from the handle. Use all thread to mount your motors. Just cut the threaded rod to length and add double nuts to the top, this will ensure it does not move.
Depending on what size threaded rod you choose you may have to drill your holes to a larger diameter. I used 5/8 threaded rod for this project, you can find it here
Step 6: Remove Cable and Spring
Use pliers to remove these, this way you can operate the shut off with your finger since you no longer have a handle and lever.
Step 7: Front Wheels
You need to replace the front wheels with casters. Otherwise, they will not turn, dragging and scraping along. If you want to maintain height adjustment and an easy bolt-on option, I recommend using these eazymow casters
Step 8: Wiring
Wire your motors and RC channels as shown in these photos. If the polarity is reversed on the motors it's no big deal but if you reverse polarity on the battery it will blow your controller!
Step 9: Mounting
I mounted my controller on a piece of wood and affixed it to the top of my battery. I used heavy duty zip ties to hold my battery in place. This makes everything easily removable for service or repair. I may add a cover for aesthetics later but for now, it functions.
That's it, have fun with your new remote-controlled lawnmower. Watch my video for the full build, there is also a parts list in the video description. My voiceover audio is terrible so use captions if you watch.
I hope you enjoyed this project!
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