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Infrared communications — Parallax Forums

Infrared communications

Buck RogersBuck Rogers Posts: 2,187
edited 2005-01-27 23:10 in BASIC Stamp
Hello from Buck Rogers
New project time.
I have here a pair of modules from (Originally HP) Agilent. Essentially they are the guts of the currently active dongle type device. They speak the IRDA protocol. I have here a sketch of having one of them connect itself to a microcontroller, with an embedded serial port.

Can one of these be attached to a BS-1?

Incidentally an example of what one would look like dressed up in a case, would be the ACT-IR200l, from ACTisys http://www.actisys.com

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Buck Rogers

www.gregg.levine.name

Comments

  • Bruce BatesBruce Bates Posts: 3,045
    edited 2005-01-26 02:41
    Gregg -

    I'm not sure whether this answers your question or not, but the MAX3100 from Maxim will go from serial to IRDA and can do so in full duplex due to an 8 character internal buffer.
    You can find some BS-2 coding help here:
    http://www.emesystems.com/BS2IrDA.htm
    You'd have to convert that code for BS-1 use. I hope that's somewhat helpful.

    Regards,

    Bruce Bates
  • Buck RogersBuck Rogers Posts: 2,187
    edited 2005-01-26 03:12
    Hello from Buck Rogers
    Nice to be well known.
    Yes thanks. I'll look at Tracy's site, and decide. The Maxim chip is one I know of, and have a few samples here.

    In fact I posted this subject, when the old board was active. I think people ignored the posting.....


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    Buck Rogers

    www.gregg.levine.name
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-01-26 17:19
    Note that IRDA was intended to be short range (a few feet?), and it's not very noise resistant. I don't know if you want to base any new designs on it. However, the MAX3100 does have an IRDA mode, as Bruce said. Note it only has an 8-byte buffer.
  • Buck RogersBuck Rogers Posts: 2,187
    edited 2005-01-27 00:18
    Hello from Buck Rogers
    I agree. Right now I am evaluating a related problem. Specifically how to create the same signals that would feed a remote control, which uses the Sony protocols. I found an article via the Generation5 site,
    http://www.generation5.org/content/2001/rob11.asp

    However one of the references quoted on the article seems to point to a link that was lost when the Parallax site was recreated with a new domain name:
    http://www.parallaxinc.com/downloads/Resources/infrared_code.ZIP

    jumpin.gif

    However it presents an interesting idea. That of connecting a single IR LED to a port pin via a resistor. And then gives a code blurb. Here's one·portion of it:

    freqout 7, 1, 38500
    The article is wrapped around a BS2 so I'd need to translate the port portion of that statement to match that of my Stamp 1. Also is that token part of the Stamp1 syntax?

    Anyway I'll keep the group aprised.


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    Buck Rogers

    www.gregg.levine.name
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-01-27 04:05
    Yes. I believe the Sony protocol uses a 600 uSec burst of 38 KHz IR to indicate a zero, and a 1.2 mSec burst of 38 Khz IR to indicate a one.

    Then I think the protocol itself uses 12 bits of ones and zeros to encode button presses on the remote.

    And yes, the Stamp can generate the 38 Khz burst with the FREQOUT statement you quote -- but only in 1 mSec resolution for the BS2. The BS2sx can get as short as you need to do the protocol with a resistor and an IR LED, I think.

    To do the recieve end, you need an IR Decoder. This is a three-pin device with what looks like a lense on the front. Radio Shack sells them. This decodes the 38 Khz burst into a simple low-high-low of the appropriate length. The BS2 can use PULSIN to find the width of the pulse.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-01-27 22:19
    Gregg & Allan,

    ·· I know this was being covered in another thread, but on the whole remote thing, has anyone mentioned the IR Buddy, which sends/receives the SONY protocol and interfaces to the stamp via serial?

    http://www.parallax.com/detail.asp?product_id=28016



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    Chris Savage

    Knight Designs
    324 West Main Street
    P.O. Box 97
    Montour Falls, NY 14865
    (607) 535-6777

    Business Page:·· http://www.knightdesigns.com
    Personal Page:··· http://www.lightlink.com/dream/chris
    Designs Page:··· http://www.lightlink.com/dream/designs
    ·
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-01-27 22:24
    Not until you mentioned it. It DOESN'T do the Sony protocol, it does the Phillips RC-5 protocol. It has very nice range, but since it only does the one protocol, it didn't seem to apply.
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-01-27 22:55
    Hmmm, I will have to double-check...I thought the Phillips RC-5 protocol was compatible with Sony devices.· I could be wrong, I haven't even gotten a set myself yet, but for some reason I thought that was the case.



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    Chris Savage

    Knight Designs
    324 West Main Street
    P.O. Box 97
    Montour Falls, NY 14865
    (607) 535-6777

    Business Page:·· http://www.knightdesigns.com
    Personal Page:··· http://www.lightlink.com/dream/chris
    Designs Page:··· http://www.lightlink.com/dream/designs
    ·
  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2005-01-27 23:10
    Okay, I looked back through my saved posts and I see where I got that from.· Apparently the SONY Protocol was discussed some time ago for it's ease of implementation without extra hardware on the BS2.· I see it's a 12-bit, 15-bit or 20-bit protocol, whereas the RC-5 is 14-bit.· I am still going to order a set of IR Buddies for possible inclusion into another project which I originally saved these messages for.



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    Chris Savage

    Knight Designs
    324 West Main Street
    P.O. Box 97
    Montour Falls, NY 14865
    (607) 535-6777

    Business Page:·· http://www.knightdesigns.com
    Personal Page:··· http://www.lightlink.com/dream/chris
    Designs Page:··· http://www.lightlink.com/dream/designs
    ·
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