MOWBOT: Resurecting a 15 year old project

[dbemowsk]

So in the early 2000's, 2002 2003 somewhere in there, I had started working on an idea for making a robotic lawn mower. I had worked on the project for a few years and kept having recurring problems with the electronics. The project ended up getting put in storage for around 15 years. I saw it rusting away in my basement and said, "I really need to bring that back to life."

THE ORIGINAL DESIGN

All the major hardware was designed by me. The main frame is a custom welded steel frame. The main deck was fabricated from a piece of acrylic that I had gotten from someone who had used it originally for a science fair computer display. The blade motor carriage was designed to fit at 3 different levels for different blade cut heights.

For the electronics, I had started using an old robotics micro-controller called OOPic. With it, I had a dual H bridge motor controller to give it differential steering. The front and rear both had custom bent aluminum bumpers which could detect directional contact with the use of micro-switches around the edge. I had side looking IR distance sensors for short range side sensing, with a front mounted ultrasonic distance sensor for longer range of vision.

I had gotten so far as to start designing an outer shell for it that I was going to make out of fiberglass. In some of the pics you will see the styrofoam shell mold I had started building.

AFTER PULLING IT OUT OF STORAGE

I didn't have it covered or protected, so in the time it has been in storage, the frame has rusted, motors and electronics are corroded, deck is dirty, the front of the acrylic platform broke off and the front part broke in two pieces. WHEW, that was a mouthful. Looking at this picture, you can see that it is in rough shape. This is before any cleanup work so I have a before and after view when it is done.

I edited that picture in gimp to give an idea of what the full deck somewhat looked like.

THE GOAL

The end goal of the whole thing is to hopefully get this thing operational. I would like to MySensorize some parts of it, though I haven't thought out exactly what parts yet. First thing is going to be to take it all apart, clean all of the parts, and then start rebuilding. I need to re-figure all of the electronics. I figure I can get better vision and control with newer and cheaper electronics.

Here are a few more teaser images.

I actually have 17 pics of this, so instead of posting them all here, I put them in an image gallery on my website.
https://dan.bemowski.info/image-gallery/nggallery/robotics/Mowbot

This is probably going to be a long drawn out project, and I don't know at what intervals I'll post progress, but I will post progress at some points.

[gohan]

Would that have been remote controlled or just autonomous mode?

[dbemowsk]

@gohan The original plan was autonomous only.

[dbemowsk]

@gohan If you look at the pics on my website, I have a pic of the OLD controller that used to run it. It was called an OOPic which was like the Arduino of the day.

[wallyllama]

Is the fact you didnt get it working an OOPic failure? (Not really a comment on what was and probably still is a difficult project, I just cant resist puns)

[dbemowsk]

@wallyllama LOL,it was sort of an epic..... sorry ..... OOPic failure.

[dbemowsk]

I still have a few of those gearhead motors in my parts bins that are not all corroded. I bought those on ebay in 2002-2003 and I think I got 6 of them in a box. They are 24V DC motors that I was running at 12V. They ran at half the speed they could have, but it was a perfect speed for mowing. I figured too that it gave me extra headroom on speed if I wanted to try going faster.

[dbemowsk]

So I started picking at disassembly of the mower project in the first steps of it's restoration. I will work on it slowly over time.

So, this is the old deck, minus the front pieces that broke off. It is a sheet of acrylic that I got for free. While disassembling parts from it, I had a number of screw posts from standoffs and some screw posts from some rusty eye bolts that broke off in the plastic. I had originally thought about cleaning it up and getting some acrylic glue to put the pieces back together, but the more I think about it, I will check prices on a sheet of lexan or plexiglass and make a new one. Acrylic is brittle, which is why pieces broke off. Lexan and plexiglass are a little more flexible.

And here is a pic of the basic frame with the drive wheels still attached. It is a bit rusty, but with a sand blaster, some primer and a bit of paint, I think it will clean up just fine.

I have some more pics from the tear-down on my website if anyone is interested. https://dan.bemowski.info/image-gallery/nggallery/robotics/Mowbot---First-Steps-In-Restoration