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Infared Circuit Question — Parallax Forums

Infared Circuit Question

ArchiverArchiver Posts: 46,084
edited 2001-07-06 22:28 in General Discussion
I purchased a "Infared Emitter and Detector (1 pr)" Cat No. 276-142 from
Radio Shack. I can not get the emitter to work. The specs on the back of
the product says Reverse Voltage: 2V; Continous Forward Current: 40mA;
Radiant power Output: 0.5mW; Wavelength at Peak Emission: 915 nm. It does
not say anything about Forward Voltage - as the other LEDs I have purchased
do. I have been assuming 0.6 V in the formula to calculate my resistor
value ( 6v Supply - .6 ) / 40mA = 135.

I have a printed copy (somewhere) about someone's reference to infared
questions. It says that I can tune my radio to 540 AM and I should be able
to hear clicking noises if I hold up a remote control to it. Or that I can
use a cam corder to actually see the infared light from the remote control.
I have tried them both on the remote control for my TV - and it works.

I have tried connecting my Infared Emitter with a resistor; I've used a 555
timer - but nothing seems to be happening. On the 555 timer, I first got it
working with a normal LED, and then substituted my IR for the LED.

I don't have a lot of experience with electronincs. Any suggestions would
be appreciated in helping me with getting my IR to work.


Thanks


Bryan Smith

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-07-04 03:20
    Any modern digital DVM will have a Diode function that will show you the
    forward voltage drop. May not work on some blue or white LEDs which can
    be as high as 2-4V.
    >
    > I purchased a "Infared Emitter and Detector (1 pr)" Cat No. 276-142 from
    > Radio Shack. I can not get the emitter to work. The specs on the back of the
    > product says Reverse Voltage: 2V; Continous Forward Current: 40mA; Radiant
    > power Output: 0.5mW; Wavelength at Peak Emission: 915 nm. It does not say
    > anything about Forward Voltage - as the other LEDs I have purchased do. I have
    > been assuming 0.6 V in the formula to calculate my resistor value ( 6v Supply
    -
    > .6 ) / 40mA = 135.
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 15:07
    I have tried various resistors; and I'm planning on putting a variable
    resistor on it and
    do some more testing. Nothing I do seems to make the IR emitter work.

    Do you have any suggestions as to why the IR emitter does not seem to be
    working ?

    Have you used the Radio Shack matched pair - emitter/detector, or do you use
    something else ?

    Thanks for your previous input, I will try doing some more measurements as
    you have suggested with the DVM.


    ==== Part of Original Message ====
    I have a printed copy (somewhere) about someone's reference to infared
    questions. It says that I can tune my radio to 540 AM and I should be able
    to hear clicking noises if I hold up a remote control to it. Or that I can
    use a cam corder to actually see the infared light from the remote control.
    I have tried them both on the remote control for my TV - and it works.

    I have tried connecting my Infared Emitter with a resistor; I've used a 555
    timer - but nothing seems to be happening. On the 555 timer, I first got it
    working with a normal LED, and then substituted my IR for the LED.


    >
    Original Message
    > From: Mike DeMetz [noparse]/noparse]SMTP:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=EWjW6qqoh0paihIm9dFPuwMQU40nPI_-uFG-p-PsEv0O-oa3hutTSyji0aB6Rfntxg9LsPMfsZmO0azm]miked@t...[/url
    > Sent: Tuesday, July 03, 2001 9:21 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Re: Infared Circuit Question
    >
    >
    > Any modern digital DVM will have a Diode function that will show you the
    > forward voltage drop. May not work on some blue or white LEDs which can
    > be as high as 2-4V.
    > >
    > > I purchased a "Infared Emitter and Detector (1 pr)" Cat No. 276-142 from
    > > Radio Shack. I can not get the emitter to work. The specs on the back
    > of the
    > > product says Reverse Voltage: 2V; Continous Forward Current: 40mA;
    > Radiant
    > > power Output: 0.5mW; Wavelength at Peak Emission: 915 nm. It does not
    > say
    > > anything about Forward Voltage - as the other LEDs I have purchased do.
    > I have
    > > been assuming 0.6 V in the formula to calculate my resistor value ( 6v
    > Supply -
    > > .6 ) / 40mA = 135.
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 15:54
    I tried the 555 circuit and it works so-so -- you have to use some tight
    tolerance parts to get it to stay on frequency. I tried the deal in the
    Parallax weekend kit I got, and it works really well. You use a Stamp 2 to
    generate your signal for the I/R LED and use one of the Panasonic detectors
    to detect it.

    The camcorder trick with the I/R diodes does work. I have one of those
    little cards from Radio Shack in my robot box that I use.

    Original Message

    > I have tried various resistors; and I'm planning on putting a variable
    > resistor on it and
    > do some more testing. Nothing I do seems to make the IR emitter work.
    >
    > Do you have any suggestions as to why the IR emitter does not seem to be
    > working ?
    >
    > Have you used the Radio Shack matched pair - emitter/detector, or do you
    use
    > something else ?
    >
    > Thanks for your previous input, I will try doing some more measurements as
    > you have suggested with the DVM.
    >
    >
    > ==== Part of Original Message ====
    > I have a printed copy (somewhere) about someone's reference to infared
    > questions. It says that I can tune my radio to 540 AM and I should be
    able
    > to hear clicking noises if I hold up a remote control to it. Or that I
    can
    > use a cam corder to actually see the infared light from the remote
    control.
    > I have tried them both on the remote control for my TV - and it works.
    >
    > I have tried connecting my Infared Emitter with a resistor; I've used a
    555
    > timer - but nothing seems to be happening. On the 555 timer, I first got
    it
    > working with a normal LED, and then substituted my IR for the LED.
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 16:20
    Just a quick comment- are you sure you have the IR LED wired in the
    correct way round? IR and visible light LED's often have the cathode
    marked in opposite ways (IE, the short lead on a visible light LED
    indicates cathode, but on an IR LED it indicates anode).

    Original Message:
    'snip...

    > Or that I can use a cam corder to actually see the infared light from
    > the remote control.
    > I have tried them both on the remote control for my TV - and it
    > works.
    > I have tried connecting my Infared Emitter with a resistor; I've
    > used a 555 timer - but nothing seems to be happening. On the 555
    > timer, I first got it
    > working with a normal LED, and then substituted my IR for the LED.
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 16:24
    The Radio Shack specs on the back of the Emitter/Detector indicate that the
    Anode of my detector should be positive, but it does not say anything about
    the emitter.
    I will verify my circuit as you have indicated this evening. Thanks for
    your input

    >
    Original Message
    > From: Peter Charles [noparse]/noparse]SMTP:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=G00PU5zjnGrPqEwPEEzcbkYaTfkIS1zgYu8KWOim647ITUrZrXX0neqFXVVozraa60x3epXrPDlqWmHsoBE]pcharles@m...[/url
    > Sent: Thursday, July 05, 2001 10:21 AM
    > To: basicstamps@yahoogroups.com
    > Subject: Re: [noparse][[/noparse]basicstamps] Re: Infared Circuit Question
    >
    >
    >
    > Just a quick comment- are you sure you have the IR LED wired in the
    > correct way round? IR and visible light LED's often have the cathode
    > marked in opposite ways (IE, the short lead on a visible light LED
    > indicates cathode, but on an IR LED it indicates anode).
    >
    > Original Message:
    > 'snip...
    >
    > > Or that I can use a cam corder to actually see the infared light from
    > > the remote control.
    > > I have tried them both on the remote control for my TV - and it
    > > works.
    > > I have tried connecting my Infared Emitter with a resistor; I've
    > > used a 555 timer - but nothing seems to be happening. On the 555
    > > timer, I first got it
    > > working with a normal LED, and then substituted my IR for the LED.
    > >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 16:26
    Is there a certain frequency I must use to make the I/R LED work ? Can I not
    connect it to a resistor then to my power supply for a simple test ?

    >
    Original Message
    > From: Rodent [noparse]/noparse]SMTP:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=yMrmn7qACxCgIIjNRIB3-uFxNMd4G361pZOyF8syUCHgbnyTmT67hpIRkDVE0aEOxTr0rxMlt_uL5DA]daweasel@s...[/url
    > Sent: Thursday, July 05, 2001 9:55 AM
    > To: basicstamps@yahoogroups.com
    > Subject: Re: [noparse][[/noparse]basicstamps] Re: Infared Circuit Question
    >
    > I tried the 555 circuit and it works so-so -- you have to use some tight
    > tolerance parts to get it to stay on frequency. I tried the deal in the
    > Parallax weekend kit I got, and it works really well. You use a Stamp 2 to
    > generate your signal for the I/R LED and use one of the Panasonic
    > detectors
    > to detect it.
    >
    > The camcorder trick with the I/R diodes does work. I have one of those
    > little cards from Radio Shack in my robot box that I use.
    >
    >
    Original Message
    >
    > > I have tried various resistors; and I'm planning on putting a variable
    > > resistor on it and
    > > do some more testing. Nothing I do seems to make the IR emitter work.
    > >
    > > Do you have any suggestions as to why the IR emitter does not seem to be
    > > working ?
    > >
    > > Have you used the Radio Shack matched pair - emitter/detector, or do you
    > use
    > > something else ?
    > >
    > > Thanks for your previous input, I will try doing some more measurements
    > as
    > > you have suggested with the DVM.
    > >
    > >
    > > ==== Part of Original Message ====
    > > I have a printed copy (somewhere) about someone's reference to infared
    > > questions. It says that I can tune my radio to 540 AM and I should be
    > able
    > > to hear clicking noises if I hold up a remote control to it. Or that I
    > can
    > > use a cam corder to actually see the infared light from the remote
    > control.
    > > I have tried them both on the remote control for my TV - and it works.
    > >
    > > I have tried connecting my Infared Emitter with a resistor; I've used a
    > 555
    > > timer - but nothing seems to be happening. On the 555 timer, I first
    > got
    > it
    > > working with a normal LED, and then substituted my IR for the LED.
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    > Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 17:26
    For Bryan Smith

    Yes, 38500 Hz is optimum frequency.

    Sid - W4EKQ
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-05 17:53
    You can power the LED from 5 volts DC (with the proper resistor) and it
    should output I/R light. Your camcorder *may* see it -- I know the I/R
    detector card from Radio Shack will.

    Whether or not your detector will see it depends on the detector. If its a
    simple phototransistor, it should see it. If its one of the I/R modules that
    looks for a modulated signal it will not. Most of these detectors look for a
    38 khz I/R beam -- constant I/R is ignored. If your receiver circuit works
    with a TV remote, assume the problem is with the detector.

    Original Message

    > Is there a certain frequency I must use to make the I/R LED work ? Can I
    not
    > connect it to a resistor then to my power supply for a simple test ?

    > > I tried the 555 circuit and it works so-so -- you have to use some tight
    > > tolerance parts to get it to stay on frequency. I tried the deal in the
    > > Parallax weekend kit I got, and it works really well. You use a Stamp 2
    to
    > > generate your signal for the I/R LED and use one of the Panasonic
    > > detectors
    > > to detect it.
    > >
    > > The camcorder trick with the I/R diodes does work. I have one of those
    > > little cards from Radio Shack in my robot box that I use.
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-06 21:37
    If you really wanna do some cool IR stuff check put the HT-12 IR
    encoder/decoder chips. Way better than doing it with a 555. A snap to
    use. Comes in IR and RF flavors.

    I would hazard a guess and say these Holtek chips are the heart of
    most of the IR remote control kits you see out there.(at a fraction
    of the price). The chips are dirt cheap, require only a few external
    components and are very easy to use. They will interface directly
    with a STAMP as well as TTL.
    Check it out at http://www.holtek.com. Follow the "consumer
    products" link. The Radioshack.com commercial catalog also lists
    these chips.

    Back to work

    BCNU

    Ric


    --- In basicstamps@y..., Rodent <daweasel@s...> wrote:
    > You can power the LED from 5 volts DC (with the proper resistor)
    and it
    > should output I/R light. Your camcorder *may* see it -- I know the
    I/R
    > detector card from Radio Shack will.
    >
    > Whether or not your detector will see it depends on the detector.
    If its a
    > simple phototransistor, it should see it. If its one of the I/R
    modules that
    > looks for a modulated signal it will not. Most of these detectors
    look for a
    > 38 khz I/R beam -- constant I/R is ignored. If your receiver
    circuit works
    > with a TV remote, assume the problem is with the detector.
    >
    >
    Original Message
    >
    > > Is there a certain frequency I must use to make the I/R LED
    work ? Can I
    > not
    > > connect it to a resistor then to my power supply for a simple
    test ?
    >
    > > > I tried the 555 circuit and it works so-so -- you have to use
    some tight
    > > > tolerance parts to get it to stay on frequency. I tried the
    deal in the
    > > > Parallax weekend kit I got, and it works really well. You use a
    Stamp 2
    > to
    > > > generate your signal for the I/R LED and use one of the
    Panasonic
    > > > detectors
    > > > to detect it.
    > > >
    > > > The camcorder trick with the I/R diodes does work. I have one
    of those
    > > > little cards from Radio Shack in my robot box that I use.
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-06 21:50
    Thanks for the information.

    >
    Original Message
    > From: iceninevt@y... [noparse]/noparse]SMTP:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=XJXtvkn5w83MvcJJyF39MHiBzPwYEGMRpDyya6SGq9fpQqkCqkegkO_qtmj_3altjD35aNX4JrjA9ESEmQ]iceninevt@y...[/url
    > Sent: Friday, July 06, 2001 3:38 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] Re: Infared Circuit Question
    >
    > If you really wanna do some cool IR stuff check put the HT-12 IR
    > encoder/decoder chips. Way better than doing it with a 555. A snap to
    > use. Comes in IR and RF flavors.
    >
    > I would hazard a guess and say these Holtek chips are the heart of
    > most of the IR remote control kits you see out there.(at a fraction
    > of the price). The chips are dirt cheap, require only a few external
    > components and are very easy to use. They will interface directly
    > with a STAMP as well as TTL.
    > Check it out at http://www.holtek.com. Follow the "consumer
    > products" link. The Radioshack.com commercial catalog also lists
    > these chips.
    >
    > Back to work
    >
    > BCNU
    >
    > Ric
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2001-07-06 22:28
    > If you really wanna do some cool IR stuff check put the HT-12 IR
    > encoder/decoder chips. Way better than doing it with a 555. A snap to
    > use. Comes in IR and RF flavors.

    The HT-12A is an excellent IC for infrared remote control. This is what we
    designed our original Fire-Stick I with. Here's a complete 2-page project
    showing how to use the HT-12A with complete schematics for our original
    Fire-Stick I: http://www.rentron.com/Fire-Stick-II.htm

    This project shows how to pump-up the infrared LED for up to 100' operation
    also.

    Regards,

    -Bruce
    webmaster@r...
    http://www.rentron.com
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