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 Robotics / 9670
Subject: 
Re: detecting goal objects at a distance
Newsgroups: 
lugnet.robotics
Date: 
Mon, 3 Jan 2000 10:07:16 GMT
Viewed: 
1054 times
  
Thanks a lot Ben!

I'm going to look for some of those IR LEDs and make some experiments.

Mario

Web page: http://www.geocities.com/~marioferrari
LUGNET member page:  http://www.lugnet.com/people/members/?m=22
Proud member of ItLUG: http://www.itlug.org

Ben Jackson <ben@ben.com> wrote:
In lugnet.robotics, Uwe Denzer writes:
Mario Ferrari wrote:

Does any of you have suggestion on what kind of IR led is more • appropriate

Well, I do now!  I bought three last night.  I got a GaAs IR LED that was
clearly made for a remote control application.  The good news is that when • it
is pointed at the LEGO light sensor it pegs at 100%!  Unfortunately it's • higly
directional (it seems to be an LED behind a lens, rather than embedded in • a
diffusing material).  I chose it because it claimed to be a 3v part, which • made
battery selection easier.  I'm going to exchange it for one of the 5-6v • LEDs
with a standard diffuse plastic body.

To power it I got 3v lithium watch batteries (biggest I could find, about • the
size of a quarter).  If I go with 6v LEDs I'll need two of them sandwiched
together.  I plan to use 1/2" heat-shrink tubing to hold the batteries • together
with electrodes (aka wires soldered to a loop of large gauge copper wire).

to make such an object? Do I need any additional circuit, or just a LED • and
a battery (and the proper resistor) are enough?

They make some LEDs with builtin resistors now.  You should make sure you • know
what kind you've got.

I imagine that - even if using such an IR LED as a beacon - roomlight • etc.
will
still be the major problem.

The LEGO sensor is far more sensitive to IR already, even without a • filter.
That's why I was choosing it (although being invisibile to humans is a • nice
side-effect).

So, I'm pretty sure that a quite simple means at the detector side would
simplify such a project dramatically: an optical IR filter.

You can get these (as well as so-called Hot Mirror filters to block IR) at • any
camera store.

--Ben


Subject: 
RCX Web Server
Newsgroups: 
lugnet.robotics
Date: 
Mon, 3 Jan 2000 12:24:19 GMT
Original-From: 
David Pfeffer <davidp@byte(StopSpammers)nik.com>
Viewed: 
1688 times
  
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Hash: SHA1

Hi all,
I've been working on a RCX web server, and it seems my project is
almost done. When I finish it, the website running off of the RCX
will be available at http://rcxonline.gbdev.org. Its not up yet, but
it will be within the next few weeks. I wrote it in LegOS (which I
can't get to work anymore... my harddrive crashed and now it won't
install (windows)... thats whats holding up my project... I hook the
IR unit and a modem up to a Basic Stamp IIx from ParalaxInc.com, to
retransmit the data in an IR unit friendly fashion. The RCX has a 5
to 4 compression routine I wrote and you can expect images on the RCX
website because of it (not linked from a real server, but actually
served directly from the RCX.) I've never been much of a hardware
guy, but if someone could design an interface to one of the sensor
and motor ports to read an EEProm, I could hold more data on it. If
my invention is sucessful, I might consider registering
www.rcx_on_the_web.com as a place for my RCX to have a perminant
location. (Just better tell the cleaning lady not to move the RCX
away from the IR beacon...)

David

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