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Questions pertaining to Infrared... — Parallax Forums

Questions pertaining to Infrared...

ArchiverArchiver Posts: 46,084
edited 2001-10-22 21:27 in General Discussion
Thanks to everyone for the servo help!

OK, I've tried everything and I cannot seem to get infrared diodes to work. I
bought them from Radio Shack, and I was hoping to use them in a Laser Tag
project I am working on (which will be easy now that I have the Basic Stamp!). I
have talked to other people about this, but no one has helped me. So, I decided
to dip into the vast knowledge that is this message board, and ask for help. I
just know there's some way to do this easily on the BS. But what is it? Any help
is always appreciated. By the way, I only have a BS1 and 2.


[noparse][[/noparse]Non-text portions of this message have been removed]

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-10-20 14:58
    First, either use normal visible LED's to verify the circuit is working,
    *or* use a video camera or one of those I/R detector cards from Radio Shack
    to verify the infrared LED is working.

    Ideally you would use the BS2 (since it can modulate the I/R diode) and a
    transistor (2N2222 is good) to drive the LED. Most I/R LED's draw too much
    current to run them directly off a Stamp pin.

    Original Message

    > OK, I've tried everything and I cannot seem to get infrared diodes to
    work. I bought them from Radio Shack, and I was hoping to use them in a
    Laser Tag project I am working on (which will be easy now that I have the
    Basic Stamp!). I have talked to other people about this, but no one has
    helped me. So, I decided to dip into the vast knowledge that is this message
    board, and ask for help. I just know there's some way to do this easily on
    the BS. But what is it? Any help is always appreciated. By the way, I only
    have a BS1 and 2.
  • ArchiverArchiver Posts: 46,084
    edited 2001-10-20 17:30
    By "modulate", I assume you mean pulse the IR diode at a given frequency
    (38 - 40Khz usually, right ?).
    Then, of course, the detectors should be modulated at the same frequency and
    be matched to the same wavelength of IR light - am I right here ?

    Regards,
    Justin.


    Original Message
    From: Rodent [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=0EmCoalYQd41pinaZs734fPEnbNT6dLedVfuKDCXFIS6ULmBybD8zDYhU4UDFCGYDMT7Y8NHAoE0N_JcsyA]daweasel@s...[/url
    Sent: 20 October 2001 14:58
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Questions pertaining to Infrared...


    First, either use normal visible LED's to verify the circuit is working,
    *or* use a video camera or one of those I/R detector cards from Radio Shack
    to verify the infrared LED is working.

    Ideally you would use the BS2 (since it can modulate the I/R diode) and a
    transistor (2N2222 is good) to drive the LED. Most I/R LED's draw too much
    current to run them directly off a Stamp pin.

    Original Message

    > OK, I've tried everything and I cannot seem to get infrared diodes to
    work. I bought them from Radio Shack, and I was hoping to use them in a
    Laser Tag project I am working on (which will be easy now that I have the
    Basic Stamp!). I have talked to other people about this, but no one has
    helped me. So, I decided to dip into the vast knowledge that is this message
    board, and ask for help. I just know there's some way to do this easily on
    the BS. But what is it? Any help is always appreciated. By the way, I only
    have a BS1 and 2.




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  • ArchiverArchiver Posts: 46,084
    edited 2001-10-21 23:10
    If the detector is a plain phototransistor, modulating the I/R really does
    not good. However, if you are using an I/R receiver module (like the metal
    can thing Radio Shack sells), then you do need to modulate the I/R. See the
    spec sheet on the I/R receiver for details.

    The detector modules are not modulated. It typically has some sort of filter
    circuit built in that rejects any I/R signals that are not at the proper
    frequency.

    Original Message


    > By "modulate", I assume you mean pulse the IR diode at a given frequency
    > (38 - 40Khz usually, right ?).
    > Then, of course, the detectors should be modulated at the same frequency
    and
    > be matched to the same wavelength of IR light - am I right here ?

    > First, either use normal visible LED's to verify the circuit is working,
    > *or* use a video camera or one of those I/R detector cards from Radio
    Shack
    > to verify the infrared LED is working.
    >
    > Ideally you would use the BS2 (since it can modulate the I/R diode) and a
    > transistor (2N2222 is good) to drive the LED. Most I/R LED's draw too much
    > current to run them directly off a Stamp pin.
    >
    >
    Original Message
    >
    > > OK, I've tried everything and I cannot seem to get infrared diodes to
    > work. I bought them from Radio Shack, and I was hoping to use them in a
    > Laser Tag project I am working on (which will be easy now that I have the
    > Basic Stamp!). I have talked to other people about this, but no one has
    > helped me. So, I decided to dip into the vast knowledge that is this
    message
    > board, and ask for help. I just know there's some way to do this easily on
    > the BS. But what is it? Any help is always appreciated. By the way, I only
    > have a BS1 and 2.
  • ArchiverArchiver Posts: 46,084
    edited 2001-10-22 15:04
    I'm wondering if you could elaborate on how to hook up the transistor?

    Although I've been dabbling in electronics for several years, I'm
    embarrassed to admit that I don't firmly know how to use the most building
    block of circuits! I'm using two IR LEDs and IR Logic Detectors
    opto-interrupt style to detect the positioning of a shutter in a camera, and
    need to turn them on only occasionally from a stamp pin. I've got a couple
    of 2N2222A transistors, are these the same as 2N2222 transistors?

    Thanks,
    Stewart


    >First, either use normal visible LED's to verify the circuit is working,
    *or* use a video camera or one of those I/R detector cards from Radio Shack
    to verify the infrared LED is working.
    Ideally you would use the BS2 (since it can modulate the I/R diode) and a
    transistor (2N2222 is good) to drive the LED. Most I/R LED's draw too much
    current to run them directly off a Stamp pin.
  • ArchiverArchiver Posts: 46,084
    edited 2001-10-22 15:28
    Except for the 2N2222's in the metal can, they are all about the same.

    Holding the transistor in front of you with the leads pointed down and the
    flat side facing you, the terminals are emitter, base and collector from
    left to right.

    I'll email you a schematic.

    Original Message

    > I'm wondering if you could elaborate on how to hook up the transistor?
    >
    > Although I've been dabbling in electronics for several years, I'm
    > embarrassed to admit that I don't firmly know how to use the most building
    > block of circuits! I'm using two IR LEDs and IR Logic Detectors
    > opto-interrupt style to detect the positioning of a shutter in a camera,
    and
    > need to turn them on only occasionally from a stamp pin. I've got a
    couple
    > of 2N2222A transistors, are these the same as 2N2222 transistors?
  • ArchiverArchiver Posts: 46,084
    edited 2001-10-22 15:34
    OOPS -- Brainfart. Here is the pinout for the transistor:

    http://www.engr.trinity.edu/~knickels/class/engr2164/s00/data/2n2222a.pdf

    Original Message

    > I'm wondering if you could elaborate on how to hook up the transistor?
    >
    > Although I've been dabbling in electronics for several years, I'm
    > embarrassed to admit that I don't firmly know how to use the most building
    > block of circuits! I'm using two IR LEDs and IR Logic Detectors
    > opto-interrupt style to detect the positioning of a shutter in a camera,
    and
    > need to turn them on only occasionally from a stamp pin. I've got a
    couple
    > of 2N2222A transistors, are these the same as 2N2222 transistors?
  • ArchiverArchiver Posts: 46,084
    edited 2001-10-22 20:55
    Rodent, Thank you for the quick reply. That schematic says it all!

    Stewart

    Original Message

    From: basicstamps@yahoogroups.com
    Date: Monday, October 22, 2001 09:35:47
    To: basicstamps@yahoogroups.com
    Subject: Re: [noparse][[/noparse]basicstamps] Questions pertaining to Infrared...

    OOPS -- Brainfart. Here is the pinout for the transistor:

    http://www.engr.trinity.edu/~knickels/class/engr2164/s00/data/2n2222a.pdf

    Original Message

    > I'm wondering if you could elaborate on how to hook up the transistor?
    >
    > Although I've been dabbling in electronics for several years, I'm
    > embarrassed to admit that I don't firmly know how to use the most building
    > block of circuits! I'm using two IR LEDs and IR Logic Detectors
    > opto-interrupt style to detect the positioning of a shutter in a camera,
    and
    > need to turn them on only occasionally from a stamp pin. I've got a
    couple
    > of 2N2222A transistors, are these the same as 2N2222 transistors?




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  • ArchiverArchiver Posts: 46,084
    edited 2001-10-22 21:27
    No problemo. That same deal works for using PULSOUT to modulate an LED for
    the 38 or 40 KHz detectors also. Just set the pin low, then do the PULSOUT.
    The main thing is you can drive the LED's harder (supply more current) than
    with just a Stamp pin.

    Original Message


    > Rodent, Thank you for the quick reply. That schematic says it all!

    > OOPS -- Brainfart. Here is the pinout for the transistor:
    >
    > http://www.engr.trinity.edu/~knickels/class/engr2164/s00/data/2n2222a.pdf
    >
    >
    Original Message
    >
    > > I'm wondering if you could elaborate on how to hook up the transistor?
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