Posted: Mar 08, 2020 4:27 am
Fenrir wrote:Yay!
I gots a half- finished (more like 1/10th finished) ardumower on my random unfinished projects bench (actually that's the entire garage).
Nice!
Maybe we can compare notes.
I have feelers out for a used wheel chair. If I can score one of those I’m set.
I think the trick might be weight distribution, and speed control. Examples on YouTube all seem to be to fast, and twitchy. I want smooth steady movement that tracks well. Some of those mowers also spin the drive wheels too easily, and seem to lose traction quite often. My solution is a bike tire with screws shot through the tube side, the heads slathered in silicone, a strip of old tube covering the screw heads/silicone and assembled with a new tube with minimal inflation before the silicone cures. 3/4”-1” screws should provide ample “bite” to keep the loss of traction to a minimum. Something like the tires used on ice racing motorbikes.
I’ll probably play with the PWM mapping/upper limits in software to keep my speed limits within my desired range. I’m sure it will require a lot of trial and error to get the gearing, wheel speed and cutting abilities to match up. I’m also considering a stepper motor driven throttle control for even more adaptive capabilities. If the grass just needs trimmed the engine need not run wide open, but during those months when we have a 4 day rotation, and the grass grows at night, I might need to crank the throttle to munch the stuff.
I have finalized my controller layout, and all that remains is some epoxy work and soldering. I’m going to play around with adding an external antenna to the RF modules of the correct length and embedding that in a rigid epoxy rail in both master and slave. This could extend the master battery life by using low power mode, and extend the range (not that I expect to need it on my small lawn). I just want to make sure not to lose comms between the modules with a running mower. Of course this too will have to be tested extensively without the engine running! I don’t want a running mower set loose on the world to follow its own devices.
My test bed, well before 24 volt motors are powered up, will be 4 LEDs. Two for each motor. One red for reverse, and one green for forward for each motor lead. The drivers I’m using need a PWM signal for forward and another for reverse. So, the simulation of the correct signals will be two green LEDs full bright for as fast forward as possible, and two red LEDs full bright for full reverse. A mix of the two, at various brightness, will indicate that the slave WIFI device/Arduino/coding is functional. This will allow me a preview of the functionality without having to spin high torque DC motors, and make corrections as needed.
RS