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Subject: 
Re: A RCX 'Beacon'
Newsgroups: 
lugnet.robotics
Date: 
Thu, 29 Jul 1999 15:54:54 GMT
Original-From: 
Laurentino Martins <LMARTINS@MARKTEST.antispamPT>
Viewed: 
1193 times
  
At 16:07 29-07-1999 Thursday , Mario Ferrari wrote:
> In lugnet.robotics, lego-robotics@crynwr.com (Cwikla, Brian) writes:
> > Well, I'm not an expert when it comes to small electronics and making them,
> > so I thought I would post this question to this list.
> > 
> > After working with the RCX for nearly a year now, I've found a tool/sensor
> > that I would really like to have, but no idea how I could implement it.
> > 
> > Basically, it works like this.  It would involve a home-brew sensor and a
> > home-brew module.  The sensor would attach to the input port on the RCX.
> > The module can be placed anywhere and emits a pulse/beep/signal.  The sensor
> > on the RCX can pick up that pulse/beep/signal and be able to tell the
> > general direction it is coming from.  It would send a number from 0 - 360 to
> > the RCX to tell it in degrees what direction it is coming from and then
> > through programming in the RCX, it could adjust it's direction to go towards
> > that signal.
> > 
> > I know there could be factors like signal bouncing off of walls and giving
> > wrong impressions as to direction to the RCX and such....  but is something
> > like this possible?  Or is there currently any method that someone is using
> > to always navigate to a certain point/area?  Any help would be appreciated!
> 
> Brian, I share your dream. It's a great idea.
> 
> Surprisingly enough just this morning I wrote an email to Al Thiele asking for
> the same thing. I'm obsessed by the problem of knowing the robot position. I
> had some success experimenting odometry, but I still need a way to zero the
> errors from time to time with an external reference point. I was wondering if
> a sort of radio beacon like the ones the planes use would be possible. One (or
> more) dedicated radio frequency (or IR) emitters, and one (or more)
> directional receiver to put on your robot and connect to the RCX.
> 
> I'd love to get values in the 0-360 range that tells the direction. But I
> could live with other simpler solutions too: the receiver returns a value
> that's higher when it is pointed toward the emitter (so I can place it on a
> rotating turret and detect the radio/IR beacon direction). With three beacons
> you could implement a true GPS-like navigation system.


Once, when I had the time to think about it, I started an auto-correction algorithm based only in odometry and map matching.
The idea was to memorize a map and at each impact with a wall and try to find if that same area was already hit in the past (looking at the map), and adjust the heading/coordinates according with the old map.
This is a processor and memory intensive task and the PC was the way to go with my CyberMaster. Unfortunately, I never found the time to finish it.
Maybe one day...

I also would like to develop some kind process to determine the shape of an object.
The idea was to create some kind of antennae using the 3 CyberMaster touch sensors so I could find (for instants) at what angle the bot has hit a wall, to identify a chair leg or even if it is a corner of a wall.
If must be mechanically possible, but I must still find a way to do it.



Laurentino Martins

[ mailto:lau@mail.telepac.pt ]
[ http://www.terravista.pt/Enseada/2808/ ]

--
Did you check the web site first?: http://www.crynwr.com/lego-robotics



Message is in Reply To:
  A RCX 'Beacon'
 
Well, I'm not an expert when it comes to small electronics and making them, so I thought I would post this question to this list. After working with the RCX for nearly a year now, I've found a tool/sensor that I would really like to have, but no (...) (27 years ago, 29-Jul-99, to lugnet.robotics)

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