Radio Control of Ugly Buster

Bill Chennault

All--

My robot, Ugly Buster, is alive and well. You might remember that he is a skid steer machine driven by five microcontrollers which communicate with each other VERY FAST via bit-signaling.·One of the very important things I've learned is that a tracked vehicle does not maneuver well by counting encoder events. Although the wheelbase is equal to the width, making it easy to turn, it still slides. Therefore, you cannot depend on turns based on encoder events. Of course, I can pretty much get whatever I want on carpet, or grass, or concrete, but when I get one to work and then switch surfaces the slippage changes. The change is enough to make navigation impossible via counting encoder events.

So, although I will add other sensors to augment the personality of Ugly Buster, what I would like to do next is create a digital radio control that will allow me to cause him to start, stop, go slow, cruise, go forward, and go in reverse. This amounts to six functions. More would be nice.

I need suggestions on the path to take. I am not interested in R/C due to its expense and the fact that eventually I want to put Ugly Buster--and his larger progeny--on the Internet for you to control. That's later. Right now, I am looking at Parallax's RF stuff. It looks like the 912MHz tranciever would allow me to communicate Stamp to Stamp, which would work but I would far rather communicate laptop to Stamp as is suggested in the documentation for the 433MHz devices.

But, I am open to any ideas. Got any?

Thanks!

--Bill

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You are what you write.

kenwtn

I am using the 433 tranceiver to control my robot and like it very much. I have a BS2 controller contected to my PC and it sends the commands onto the robot BS2 Controller. I have a 1/2 acre lot and no problems controlling it anyway on my lot.

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Keep buying replacement parts and sooner or later you will get it RIGHT!

MSDTech

I'm using a bluetooth adaptor; eb500 on robot and linksys on a PC to control a robot.

Handtool

The eb500 is a nice solution if the limited range isn't a factor.· I've used it with hyperterminal as well as·a VisualBasic interface I wrote to control my tracked robot.· It would also make your transition to internet control fairly straight forward.

http://www.youtube.com/watch?v=CguCTJyuJpo

Bill Chennault

All--

Thank you for the ideas. It looks like I need to do some experimentation. (Isn't it always like that?)

I want to build a remote controlled/robotic lawn mower so I can cut my grass from my easy chair and see what it is doing on my big screen above the fireplace. Initially, the "robotic" part would be merely to help automate some ordinary functions on the mower.

I have an EB500. Perhaps I should stick a BOE with the EB500 in it out in the yard and see if my laptop's Bluetooth interace will still see it.

--Bill

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You are what you write.

kennet

Bill- The only reason Ugly Buster's tracks have slippage problems is because Ugly Buster's Mass isn't sufficient enough. Actually,a combination of several factors lead to this type of slippage,among them are [noparse]:([/noparse]1) to little Mass(weight),(2) to much RPM·from the drive train,(3)Type of·surface being driven over and (4) tread or wheel material. With enough Mass ,you can probably compensate for deficiencies in other areas. The important thing to remember is that Robots soon become self-serving devices that begin to take on a life of it's own.Example?: The easiest way to add Mass is to use a much larger battery pack which is good because the added weight will make the motors work harder and drain the current one·much faster·anyway.See what I mean?

Ken

Bill Chennault

Ken--

I am going to think about what you said. Ugly Buster's tracks are too narrow, for sure. Unless I find something IDEAL (they really have to be sturdy), they will stay that way. I will also talk to my 94 year-old Dad. He drove BIG tracked vehicles most of his life on various surfaces, from swamps to Cheyenne mountain.

By the way, Ugly Buster weighs 24 pounds and is driven by two, 12 volt batteries. If he gets much heavier, this old guy ain't gonna be picking him up! [noparse]:)[/noparse]

Thank you for thinking about this for me. (Maybe I'll check out those Lynx Motion tracks . . . )

--Bill

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You are what you write.

kennet

Bill just an added thought. I ,like you, was once at a cross roads in my robot building.I had to make a choice. Do I give up the ability to carry my own robots myself and thereby limit their size·,complexity and range or do I take the next step and make them truely autonomous . I decided that if my robots were to be of any use, in and around the house ,I couldn't burden myself with weight issues .Worrying about weight will only limit the effectiveness of any robot.I have wheel chair ramps all over the place.And if a robot ever became disabled I converted an old hand truck to cart it into my workshop.If I needed to put it on the work bench, I start to disassemble the part which needs working on, not the entire robot.The most important part of the robot is a good solid base and detachable componants built on to·the base. My wife is standing over me shaking her head. It's just a small price I pay.When my grandkids come over they go WOW!!!!!

Ken

Bill Chennault

Ken--

First and most important . . . I bet that is the neatest feeling when the grandkids go 'wow'! They will remember those experiences FOREVER! This means you are immortal.

I will experiment with "digital" radio control (I don't know what else to call it) for a bit on Ugly Buster whom is like my bestest friend because the cats that I hate with a true and pure passion are terrified of him. Then, after I feel confident with this type of remote control, I will build the yard beast which will cut my grass. Ugly Buster and his tracks do well in the grass, but the Yard Beast (maybe I've just named him!) will do at least as well with turf tires.

I am thinking about four six inch blades turning at about a thousand RPM. I have no clue if this is fast enough or too fast. All I know·is that it is easy to buy 12vdc motors that will turn them at that speed. I guess I could go down to my local used lawn mower shop and ask them how fast a "regular" gasoline lawnmower engine turns at full throttle. They are good folks and will doubtless give me a good approximation. (I looked all over my lawnmower and could not find an RPM rating.)

--Bill

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You are what you write.