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[DPRG] mower musings

Subject: [DPRG] mower musings
From: James Vroman vroman at mail.airmail.net
Date: Wed Aug 9 10:21:29 CDT 2000

Jim Brown wrote:
> Well, I was daydreaming and thought how cool it would be to
> have a million dollars and just design and build any old robot I
> wanted to.  Poof, I'm not a millionaire, so instead of hiring my
> own design team, I thought I'd just put some questions out to
> see what everyone else thought of a robot mower design.
> When the robomow was donated, I was enthusiatic about it,
> and then when I realized what it consisted of, I was disappointed.
> So, using the robomow as the basis of a discussion about robot
> mowers, what would be your wish list for a robotic mower and
> what would you not want a robotic mower to have?
> 1.  Drive Train or Platform?
>     a.  Pathfinder robot 6 wheel platform.  Two wheels drive it,
>         and the 4 outer wheels turn freely.  (I'm not sure that's how
>         it works).

Would look cool but expensive.

>     b.  4 wheel drive and 4 wheel steering.  The platform would be
>         square with a wheel on each corner.  Each wheel would have
>         steering so that it could turn on a dime and remain stable.

Too easy to break - too many parts = low reliability

>     c.  2 wheel drive and 2 wheel steering.  The platform would be
>         circular with a drive wheel on the left and right side to drive
>         like a tank and a wheel in front and back to stablize.
>     (What does the robomow use?)


> 2.  CPU or hardware
>     a.  laptop connected to some basic drive board.  (could be programmable).

too expensive - not rugged enough

>     b.  HC11 - nothing else in the world matters!

>     c.  8051 - nothing else in the world matters!

>     d.  8 pin pic - nothing else in the world matters!
use as sub processors to a main processor - no preference
>     (What does the robomow use?)
> 3.  Intelligence for navigating yard
>     a.  Bump and go (yuk)  (isn't this what robomow uses?)

yes - as part of a navigation system - ie don't cross the imaginary

>     b.  GPS or some sort of home made positioning system just for this
>         application.

GPS is too expensive.

>     c.  Sonar and IRProx and landmark mapping to navigate.

 Yes to both as part of an overall system

>     d.  None, just a drive and sensor board and a serial or eithernet radio
> link.

>     e.  Software mapping via learn and playback.
Yes as part of a system
> 4.  Cutting mechanism
>     a.  Steel blades like a regular lawn mower
Too much mass
>     b.  Weed Eater type nylon string (safer)

too easy to break unless there is a better reel out mechanism.

>     c.  Nylon blades like a gas weed eater (safer)
>     d.  CO2 or YAG laser

   (what does robomow use)
> 5.  Safety
>     a.  Proximity detector

>     b.  Sound detector (hand clap to turn it off - clap on clap off)
>     c.  blood detector (just kidding)
triggers the wash cycle and evicence removal bot.

     (does the robomow have any safety devices?)
>     d.  Will it shut itself off if someone picks it up?

Yes and yell for help

> 6.  Security
>     a.  If someone picks it up will it sound an alarm
>     b.  Password start so that just anyone couldn't start it (child proof?)
     c.  Lojack transponder :-)
>     d.  Tesla 1Mvolt deterrant system.

Also used as rodent removal system

> 7.  Power refresh
>     a.  Power station that the robot has to find when detects power is low.
>     b.  None needed - raises the price for no good reason.
D cells get expensive
>     c.  Solar panels to help lengthen run time

Charge and roam mode

>     d.  Efficient batteries
Are there?
>     e.  Should allow you to plug in a new battery without forgetting what it
>         has accomplished so far (battery swap).


>     f.  Ion beam power infusion with tracker station.


> 8.  Cutting motor
>     a.  Electric so that it has one source of power
>     b.  Gas - you can only get good cutting with a gas mower?

For the industrial model

>         1.  How would it refill itself
Find a full service station

>         2.  How would it start itself and stop itself (not impossible)

Electric start motor
>     c.  Turbine
Mil spec version

>     c.  CO2 laser beam cuts grass the best

Too many safety mirrors around the yard

> 9.  Skin
>     a.  Man if it doesn't have a flame paint job I ain't gonna buy it

Popular in mexico

>     b.  Chameleon green to make it less noticable.

Stealth version

>     c.  See thru so I can erase eproms... er, um, I mean see the insides.

So it will match the persons phone, stapeler and personality.

> 10.  Feedback or Display
>     a.  Is an LCD output practical (will it go bad outside in the heat)
Won't work long in texas

>     b.  Is an LED display practical (can you see it)
Shroud it
>     c.  Voice or sound output for feedback

> 11.  Cleanliness
>     a.  should it be able to do some sort of self cleaning to keep it from
>         getting full of grass

Mulch man

>     b.  Should there be some type of cover over the buttons to keep the
>         grass out.

sealed plastic keyboard

> 12.  Manual control
>     a.  Should have a radio control mechanism (with TV feedback :-)
monitor camera - more entertaining than most shows on tv
New tv show Survivor - for moles
>     b.  Should have a bar to push it around the yard if need be.
Just a removable tow bar
> Other questions:
>     What other mowers are there out there and how do they work or have
>     What would be a good price for a mower - how low before you'd buy one
>     If it wasn't re-programmable, would you want it.

Not for the general public and the robotacists will hack it any way.

>     If it was re-programmable, would that be safe?
>     How much do you think it would cost you personally to make one
>         (let's not get into cost of time or insurance, just the cost of parts)
>     How long would it take you to make one.
>     How does robomow sidestep the issue of safety - wasn't that a big
>         liability with robotmowers why so many wouldn't build one?
>     Is an LCD output practical? (will it go bad outside in the heat)
>     Is an LED display practical?  (can you see it?)
>     How do you keep the robot from going into the neighbor's yard?
>         (that's the one good thing about a buried AC cable, but how do you
>         get those strips of grass by the street by jumping the sidewalk:
>         it's hard to bury cable in the sidewalk.)
>     Other ideas for a robot mower?
>     Daytime or nighttime running lights?
>     Flashing LEDs for the cool factor?
>     Have a robot mower contest (my yard could be used.  8-)
> So I guess what I'm asking is, what robomow should have been?
> What would be the ideal robot mower?

Anyone have teen age kids..............................

> --
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