 | | | | | | |
| |
|
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
| | | | | | | | | | | | | | | |
Ben Jackson wrote:
>
> You can get these (as well as so-called Hot Mirror filters to block IR) at any
> camera store.
>
> --Ben
Well, I knew that camera stores sell IR blocking filters but IR transmission
filters? Are you sure? (What would be the purpose for normal photography?)
Uwe
| | | | | | | | | | | | | | | | | | | | |
In lugnet.robotics, Uwe Denzer writes:
> Ben Jackson wrote
> > You can get these (as well as so-called Hot Mirror filters to block IR)
> > at any camera store.
> Well, I knew that camera stores sell IR blocking filters but IR transmission
> filters? Are you sure? (What would be the purpose for normal photography?)
IR Photography, of course. Lookup Kodak HIE, for example. The filters you are
looking for are Wratten #87 and 87C. If you look at them they appear to be
black because they pass no visible light. I believe the difference between the
two is exactly which IR wavelengths they pass, but I don't remember the
technical details. I'm sure they're on the Kodak website.
--Ben
| | | | | | | | | | | | | | | | | | | | | | |
Ben Jackson wrote:
> IR Photography, of course. Lookup Kodak HIE, for example. The filters you are
> looking for are Wratten #87 and 87C. If you look at them they appear to be
> black because they pass no visible light. I believe the difference between the
> two is exactly which IR wavelengths they pass, but I don't remember the
> technical details. I'm sure they're on the Kodak website.
>
> --Ben
OK, thanks for the info. That's interesting. I'll look for it.
Uwe
| | | | | | | | | | | | | | | | | | |
| |
|
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@bytenik.com=NoMoreSpam=>
|
Viewed:
|
1670 times
|
| |
|
-----BEGIN PGP SIGNED MESSAGE-----
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
-----BEGIN PGP SIGNATURE-----
Version: PGPfreeware 6.5.2 for non-commercial use <http://www.pgp.com>
iQA/AwUBOHCU8mU1FANHPcR9EQL7PQCeILf1PTbPR9i1rd/tsEFhZKz/iEoAoJbm
a7gLhKHntrFwzmr0LikOTcD4
=d89I
-----END PGP SIGNATURE-----
| | | | | | |
