RE: PC Infrared Receiver/Transceiver

["Ian Lowe" <ian@xxxxxxx>]

Quinten,

This is just what I am looking for! the only problem will be with how much
"pre-processing" the IR tower does.. It looks reasonably complex
internally,
rather than just being a dumb device.

If it can record the raw stream, and play it back, then we are set.. (says
Ian, glancing at the Lego Mindstorms box behind him ;) )

Where do you get this girder software, and I'll give it a try..

Ian.

-----Original Message-----
From: Quinten Uijldert [mailto:yahoogroups@xxxxxxx]
Sent: 18 January 2002 10:18
To: ukha_d@xxxxxxx
Subject: [ukha_d] PC Infrared Receiver/Transceiver


Browsing the Girder ( www.girder.nl ) forums I saw a post from someone
asking whether it supported the Lego Mindstorm IR Tower (see
http://www.pldstore.com/pitsco2_30/finditem.cfm?itemid=246
for a picture).
Not knowing what it was, I did some searches on Google and found the
following link http://www.crynwr.com/lego-robotics/
(see Communication
section).

"The RCX (which is the unit on the Lego robots) uses a 38kHz carrier,
which
is pretty typical for TV remotes. As for the sampling rate, the RCX runs at
2400 bps, which makes each bit approx 417us. Sony remotes (which aren't the
fastest), use pulse widths of 600us and 1200us, so we're in the right ball
park. I think a learning remote would do pretty well."

Another search revealed this page http://graphics.stanford.edu/~kekoa/rcx/
(see Hardware/IR Transceiver), which shows the internals of the IR Tower.

This is what I know happens:

1) The PC sends digital data over the serial port and the IR Transceiver
will decode this into an IR signal.
2) The IR Receiver receives an IR signal and decodes that into digital data
which it sends over the serial port to the PC.

Now onto the questions. I hope someone can confirm this for me.

If I where to use a program that can capture data from the serial port
(something like Girder, or custom written) and send the data back onto the
serial port, would I be right in thinking that using the IR Tower on the
serial port I can capture the IR signal, store it and play it back at a
convenient time and it would then output the same IR signal that it
received? Do the IR Receiver and Transceiver work like that?

If the answer is yes to those questions, then there is a very cheap
PCBlastir/RedRat2 like device out there: £15 + vat (see
http://freespace.virgin.net/richard.dee/dactauk.html
).

Q.

Oh, and before you ask, there is no way of buying them online, as Lego only
intends to sell them to schools (for robotic projects, etc). The UK
distributor Commotion Ltd ( 01732 773399 ) does however sell to individuals
and accept telephone orders. They will also send you a catalogue if you ask
them.


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