DIY RC lawnmower

dmcke5

10 µW
Joined
Apr 2, 2014
Messages
6
Hi guys, been a long time since I last posted here!

I'm currently converting a push lawnmower to be radio controlled in the hopes that I'll be able to mow the lawn from the comfort of my lounge! (with the help of a wireless video link, of course).
I bought a couple of cheap used kids electric scooters and salvaged some 150w brushed motors from them. I've built a frame and I'm close to being finished with the mechanical side of things (using a friction drive onto some trolley wheels for my drive).
My problem currently is tracking down an appropriate motor controller. I want to run 24v, be able to reverse if required, be able to supply up to about 20a and most importantly, cheap! Does anyone have any suggestions on what I might be able to use? Standard RC controllers are out of the question as most of them are limited to 12v. There's plenty of robot style motor controllers around that would do the job, but they cost more than double what I've spent on the rest of the project in total so far and I'm on a tight budget! Whatever I end up using, I need a way to control it via a PWM signal from my radio controls receiver.

I'll post some photos later if anyone is interested :D

Cheers!
Daniel
 
4qd.co.uk has brushed controllers with reverse; they run off potentiometer throttles so you could use RC servos to physically control the pots, and switches for reverse/forward.

I'm sure there's others like that out there too.

ALternately, you can build your own. If you look around here for Jeremy Harris' simple BLDC motor controller thread, the chip he uses can be used for brushed as well as brushless, so you could adapt his power stage to a brushed reversible version if you know enough basic electronics.


BTW, you could also build a "reversing contactor" setup for each controller/motor, and use cheap brushed scooter controllers.
 
agniusm said:
There are and better/cheaper?! options like sabetooth 25x2

Also, check out my build:
https://endless-sphere.com/forums/viewtopic.php?f=7&t=52615&p=781179&hilit=Lawnmover#p781179

Nice, looks like both our builds are fairly similar. The Sabertooth 2x25 is going to cost me about $200aud which I wouldn't consider a "cheap" option. I was thinking about electric bike motor controllers this morning, they are cheap and readily available and use a hall effect sensor for the throttle (which I'm pretty sure I could emulate with an arduino). Trouble is, I'm pretty sure they don't do reverse which would probably lead to my mower getting stuck in corners frequently!
Any other ideas? I'd really like to stay under about $100 for my motor controller if possible.

- Daniel
 
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