[Q] Squeak as IR Remote Control, was: Re: Lego Mindstorm and Squeak

Dave Hylands dhylands at broadcom.com
Tue Apr 2 23:36:27 UTC 2002


I'm not sure what you mean by "Consumer IR".

Lego Mindstorms uses a really simple IR protocol. I copied the following
from: http://www.crynwr.com/lego-robotics/ under Communication:

    "The IR protocol associated with sending a "message" 
    to the RCX is pretty simple. Bit encoding is 2400 bps, 
    NRZ, 1 start, 8 data, odd parity, 1 stop bit. A '0' 
    is coded as a 417us pulse of 38kHz IR, a '1' bit is 
    417us of nothing. 

VCR type remotes use one of several protocols, which usually involve some
sort of carrier/non-carrier sequence to send a single bit. This link
describes a variety of the remote control protocols:

The iPAQ uses IrDA, which is yet again a different protocol.

LIRC exists to hide most of the details of how a particular protocol works
and allow you to get on with sending data.

Dave Hylands

> -----Original Message-----
> From: Henrik Gedenryd [mailto:h.gedenryd at open.ac.uk]
> Sent: Tuesday, April 02, 2002 9:54 AM
> To: squeak-dev
> Subject: [Q] Squeak as IR Remote Control, was: Re: Lego Mindstorm and
> Squeak
> I've been looking at various approaches to using Squeak to 
> send Consumer
> infrared remote control signals.
> I've been looking at LIRC and at various places around the 
> web but haven't
> found anything that seems easy to adopt. I am specifically 
> looking for an
> iPaq solution, but a cross-platform approach would be desirable.
> Has anybody done anything with Squeak in this area? I know 
> the Mindstorm kit
> uses consumer IR.
> My guess is that it isn't too hard to code, if one only knows 
> what one's
> doing (and I don't). A Slang primitive for sending the 
> signals, and then the
> rest in ordinary Smalltalk. The problem with the primitive seems to be
> getting the timing right.
> Henrik

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