Subject:
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Re: POC Exploration Robot
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Newsgroups:
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lugnet.robotics
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Date:
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Fri, 17 Sep 2004 02:12:05 GMT
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Viewed:
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1106 times
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In lugnet.robotics, Rob Stehlik wrote:
> In lugnet.robotics, Mathieu Lalonde <e0nblue@ssl-mail.com> wrote:
>
> > I am posting to this list to ask the community about the feasibility of
> > such a project, before we invest a significant amount of money into
> > Mindstorms parts:
> >
> > The robot would consist of two RCX microcontrollers coupled with a
> > variety of sensors relevant to our project (ie: temperature, atmospheric
> > pressure, humidity, light, etc) and a Vision Command Unit (or whatever
> > Lego calls it’s QuickCam rip-off), all mounted on a 4 wheel drive (or
> > maybe a synchro drive). It would support two modes of operation:
> > auto-pilot and manual.
>
> Mathieu,
>
> I think this project is defenitely doable. My first bit of advice: don't build a
> synchro. This will add a huge amount of complexity to the project. The great
> thing about synchros is the navigation accuracy, but the downside is the
> rotating wires and sensors. And with Lego, you are really limited by the size
> you can build synchros. The more gearing you have to put in the steering, the
> sloppier it will be. But, if you insist on building a synchro, you might get
> some ideas on my page here:http://sparky.i989.net/rstehlik/firefighter.html
>
> > The first RCX’s IR module would be used for communication, and the
> > second IR module would be used for proximity detection (in combination
> > with a light sensor).
>
> My advice: get a custom RCX-compatible IR proximity sensor from hitechnic or
> mindsensors or technostuff. You will get much better resolution from it. And it
> leaces your IR port free for communication, which will be essential.
>
>
> > <>…So, here come my questions: Is the whole thing feasible? What would
> > you do differently and why? What major problems are we bound to run
> > into? What are the drawbacks of the choices we made (BrickOS instead of
> > NQC or Lego’s devel software, using two RCXs, using a proximity
> > detector, using a 4 wheel drive vs a synchro drive, etc)? <>
>
> Using two RCX's is... interesting. Splitting up the sensors between controllers
> is sometimes difficult to do. Because the IR communication is quite slow, you
> want to make sure that the motors correspond closely with the sensors for each
> brick, but this isn't always possible.
>
> > PS: If some people show interest in our project, I will gladly keep you
> > guys updated with pictures and info as we progress.
>
> I would be interested. And I would be happy to share from my experience as well.
>
> Rob
Perhaps an RCX and a CyberMaster (radio) would be easier? That way you can talk
to both at the same time, you get more sensors and the built-in tachos in the
Cybermaster for reasonable dead-reckoning (add an after market compass for
improved accuracy). I'd also recommend static and active muxes for more sensor
ports.
I use a CyberMaster for movement, touch and IR sensing, and mount an RCX on top
for sonar and compass. I talk to both simultaneously from a PC and put the
smarts in the PC software. The RCX loses range before the Cybermaster (10m
range), so I can bring the robot back into IR range.
You could consider a radio camera to remove the tether. (Bounce the IR off the
ceiling, and have the IR tower on a boom to keep it close to the robot.)
You can get Cybermasters from ebay.
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Message is in Reply To:
 | | Re: POC Exploration Robot
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| (...) Mathieu, I think this project is defenitely doable. My first bit of advice: don't build a synchro. This will add a huge amount of complexity to the project. The great thing about synchros is the navigation accuracy, but the downside is the (...) (20 years ago, 16-Sep-04, to lugnet.robotics)
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