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How to program and connect to a BS2 Photoresistor a and IR Transmitter to use i — Parallax Forums

How to program and connect to a BS2 Photoresistor a and IR Transmitter to use i

hvilla01hvilla01 Posts: 19
edited 2006-09-11 04:44 in BASIC Stamp
Hi all,

I want to connect to a BS2 Photoresistor a and IR Transmitter to use it as a proximity sensor.
Any help will be very much apriciated.

Humberto

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2006-09-10 03:06
    Parallax's Robotics book (downloadable from their website) has a variety of examples of the use of an IR LED and IR Sensor with a Stamp for a distance/obstacle sensor. The IR Sensor is more sensitive than a photoresistor and more directional. It's also tuned to a specific frequency of pulsed IR that is generated by the Stamp with the IR LED. The modulated IR helps reduce interference with other light sources (like sunlight or incandescent indoor lighting).

    You still could use the photoresistor, but the other is easier and more reliable. The book does have some examples of the use of a photoresistor as well.
  • hvilla01hvilla01 Posts: 19
    edited 2006-09-10 03:58
    HHi Mike,

    Thanks for your promp response, I can't find this book at parallax?

    Humberto
  • Mike GreenMike Green Posts: 23,101
    edited 2006-09-10 04:01
    Here's the link: <http://www.parallax.com/dl/docs/books/edu/Roboticsv2_2.pdf&gt;
    Most of the books on this page are free to download: <http://www.parallax.com/html_pages/products/books/books.asp&gt;
  • hvilla01hvilla01 Posts: 19
    edited 2006-09-10 04:27
    Hi Mike,

    Sorry for all this questions but I am new in this, on this book only shows the use of infrared detectors (3 pins) and infrared leds, I only have Photoresistor (2 pins)a and IR Transmitter .

    Regards
  • Beau SchwabeBeau Schwabe Posts: 6,559
    edited 2006-09-10 04:49
    A Photoresistor is designed to respond more closely to what the human Eye responds to. In other words, it's not going to be very sensitive to IR light, you need a photo-transistor or
    IR detector LED to do what you want.

    IR detector:
    http://www.parallax.com/detail.asp?product_id=350-00014

    IR emitter
    http://www.parallax.com/detail.asp?product_id=350-00003

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • hvilla01hvilla01 Posts: 19
    edited 2006-09-10 05:23
    You are right it would be better to use the Infrared Receiver, my problem is that I live in Guadalajara Mexico and is not easy at all to find them. There is another way to do it this is a page that shows an example *it is in spanish but has a lot of pictures and schematics the problem is how to program the BS2 to use them as IR sensors.

    http://www.chilebot.cl/guias/sensor-ldr.php#comment-43
  • JonathanJonathan Posts: 1,023
    edited 2006-09-10 16:16
    Hvilla,

    You can scrounge an IR receiver from a VCR. They all have them, but you may have to experiment a little to figure out the frequency.

    Jonathan

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.madlabs.info - Home of the Hydrogen Fuel Cell Robot
  • hvilla01hvilla01 Posts: 19
    edited 2006-09-10 17:45
    Hi Lonathan,

    I only have the emiters, I dont have any equipment that I dont use.
  • Beau SchwabeBeau Schwabe Posts: 6,559
    edited 2006-09-10 18:04
    I'm not sure that these would be any easier to find, but a "solar cell" would be more sensitive to IR than a Photo cell.

    BTW) The link that you provided uses a WHITE LED not an IR LED. In the parts list for that circuit "LED Blanco cristalino" translates to a "CLEAR WHITE LED"

    What you are asking with the IR LED and photo resistor is like trying to see in the dark with a pair of sun glasses.

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    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.
  • hvilla01hvilla01 Posts: 19
    edited 2006-09-11 02:47
    I have an IR LED amnd the and a photot resistor can this help?
  • Beau SchwabeBeau Schwabe Posts: 6,559
    edited 2006-09-11 04:44
    Humberto,

    No, the IR LED will not work with the photo resistor.

    There are two possibilities that I can tell:
    · 1) Any visible LED such as GREEN,RED,YELLOW,BLUE, or WHITE will work with the photo resistor.

    · 2) A solar cell, photo transistor, or IR receiver LED will work with the IR emitter LED.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Beau Schwabe

    IC Layout Engineer
    Parallax, Inc.

    Post Edited (Beau Schwabe (Parallax)) : 9/11/2006 6:09:51 AM GMT
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