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Subject: 
Re: Wireless Robots
Newsgroups: 
lugnet.robotics
Date: 
Sun, 21 Nov 1999 22:28:04 GMT
Original-From: 
Pete Sevcik <SEVCIK@FLASH.saynotospamNET>
Viewed: 
615 times
  
Matt,

I have built a lego robot controlled by a PC, using an IR link to communicate
commands.  It used the same IR technology as Mindstorms, but had an
omni-directional IR link on the robot.  The problem is link speed.  For reliable
communication, you need an error recovery protocol on the link.  I designed a
lightweight protocol, which worked well but added about 5 bytes of packet
overhead.  At 1200 baud, it takes too long to get data to the PC, and get the
response back to the robot.  e.g  the sensor detects a wall, but by the time you
get that info to the PC, and get back a command to turn, you have already hit
the wall.  IRDA technology is faster, but the distance is limited to 3 feet.
Radio links would be fine, but the low cost links are limited to about 1200
baud.

I was trying to do all the processing in the PC.  The technique might work if
you found a way to split the work.  Do  tasks that require a quick reaction time
within the robot.  Send the slower, more difficult tasks, back to the PC.  If
you use a video camera, send the video data as analog, directly to the PC.

    - pete.



Matt Ramadanovic wrote:

Has anyone tried to use wireless networking to control a legorobot?
IP programming in VB is easy and I was thinking of making a robot
which uses the RCX as its medulla and a stripped down laptop with
a PCMCIA Ethernet adapter as the cerebrum. The idea is to have a
digital camera mounted on the thing sending back video along with
passing instructions to the RCX (most of the bandwidth would be unused
if it was just sending instructions). The command console would sit on
a regular PC and would host an app that talks to the "brain" of the robot.
I don't have my kit yet so I have not tried programming a brick - though
have
seen the .ocx. I was thinking of creating functions in assembly and
compiling
a .dll in Delphi that VB programs could make calls to add functionality. Has
anybody tried this approach yet? Once I get the hardware, anyone want to
collaborate on a .dll?

Matt


--
Pete Sevcik     sevcik@flash.net
Techno-stuff Robotics
http://www.flash.net/~sevcik/
Robotics for FUN !



Message has 2 Replies:
  Re: Wireless Robots
 
Hi Pete, I have been reading about AI concepts a lot lately (and my partner here at work has his doctorate in AI), so I have some thoughts about your comments below: (...) time you (...) hit (...) [snip] (...) if (...) The current path in robotics (...) (25 years ago, 22-Nov-99, to lugnet.robotics)
  Re: Wireless Robots
 
(...) reliable (...) you (...) Would you consider making the RIS perform the check or just sending a verbatim copy of what it gets to the sender (two way radio) and making the PC check that the information was sent OK. I know that a bad packet from (...) (25 years ago, 22-Nov-99, to lugnet.robotics)

Message is in Reply To:
  Wireless Robots
 
Has anyone tried to use wireless networking to control a legorobot? IP programming in VB is easy and I was thinking of making a robot which uses the RCX as its medulla and a stripped down laptop with a PCMCIA Ethernet adapter as the cerebrum. The (...) (25 years ago, 20-Nov-99, to lugnet.robotics)

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