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Another newbie needs suggestion — Parallax Forums

Another newbie needs suggestion

Dr_LomaxDr_Lomax Posts: 3
edited 2005-03-11 01:18 in BASIC Stamp
I want to use the stamp module to create a remote controller for my PC. I am wondering which module & board should I get? I am currently a PhD student at Georgia Tech.

I want to perform the follwoing tasks:

1. Read and understand IR signals fired from a IR remote (will require IR reciever from components page).
2. Send ASCII text and strings from from the serial /usb of the dev board and display them on the Hyperterminal
3. Read IR signals from a remote, decode them and send Binary/Hex equivalent Strings to display on the Hyperterminal for further processing to recognize which key was pressed.

Your help is appreciated.

Thanks

Comments

  • steve_bsteve_b Posts: 1,563
    edited 2005-03-10 03:08
    The Basic Stamp 2 should meet your needs!
    Get the Board Of Education (BOE)...it comes with an onboard regulator, programming port and a small breadboard for prototyping!

    You'll want some IR decoder modules!· you can buy IR LEDs and detectors...but these aren't what you want (at least as far as the LEDs go).
    Parallax has an IR kit on their site too!· go check it out....a product called IR Buddy comes to mind too!

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    Steve
    http://ca.geocities.com/steve.brady@rogers.com/index.html
    "Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
  • Dr_LomaxDr_Lomax Posts: 3
    edited 2005-03-10 04:15
    The IR buddy seems to be pretty pricey as compared to just the $3 IR receiver. However, I only need to recieve signals from a remote, I believe the IR buddy does 2-way communcation. Wont I just need to connect the IR reciever to one of the IO pins?
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-03-10 15:19
    The IR-Buddy is limited to the Phillips RC5 code -- which it recieves and sends really well, by the way.

    Any 'remote's IR control is based on sending a series of bits to the recieving device. A 'bit' is a certain duration of signal. The signal is a 36, 38, or 40 Khz square wave imposed on an IR-LED -- basically, it blinks on and off that fast for the 'bit' time.

    When the IR-Decoder sees the blinking, it generates a signal of the 'envelope' of that wave. Basically, as long as the LED is blinking, the output of the IR-Decoder is low (it's output is high, when it sees no signal).

    Now, though each vendor uses very similar hardware to generate the 'blinking', each one has a different set of 'bits'. Thus we have the Phillips RC5 Protocol, the Sony Protocol, etc.

    As an example, the Sony protocol defines a '1' as a 600 uSec pulse from the decoder, and a '0' as a 1.2 mSec pulse. (I may have those backwards). The BS2 can detect pulse widths in 2 uSec increments, so you'll be okay here.

    The BS2 has a hard time SENDING these signals, since it uses FREQOUT to do this job, and it can only send in 1 mSec increments. Thus using the BS2 for a receiver is do-able. Using it for a transmitter -- well, it depends on the protocol if it can be done at all. If you add a little hardware (a 555 based 38 Khz oscillator, basically) and use PULSOUT to control it, then you CAN do some protocols with the BS2.

    It sounds like you mostly want to recieve -- so as the above discussion shows, you should be OK with the BS2.· Finally, to answer your question, yes, all you have to do is connect +5 and Vss to the IR-Decoder, and connect the signal to a BS2 pin.· You will have to select a protocol supported by your remote (there's hundreds -- the Sony protocol is pretty standard) and code the BS2 to recognize it.· All do-able.
    ·
  • Dr_LomaxDr_Lomax Posts: 3
    edited 2005-03-11 00:31
    As long as I can recieve a changing binary pulsetrain, thats all I need. For there I can pickup almost any remote and study its signals and use the BS2 to understand it and output that to the hyperterminal. Does the board of education discovery kit contain examples for this app?
  • allanlane5allanlane5 Posts: 3,815
    edited 2005-03-11 01:18
    No. I highly recommend the new Logic Analyzer module for this. Hook up your IR-Decoder to one of the pins of the BS2, plug in the L-A socket, and record what the protocol looks like on your PC.
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