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IR PhotoTransistor — Parallax Forums

IR PhotoTransistor

ArchiverArchiver Posts: 46,084
edited 2004-06-30 19:44 in General Discussion
I need to find what RL should be used on a Radio Shack PhotoTransistor (NOT
THE DECODER, JUST THE PhotoTransistor that comes packaged with a LED)

This could be either as a Common Cathode or Common Anode setup to use this
as a switch. If connected to P3, for instance, I would have a 1 or 0 if the
LED was passing to the PhotoTransistor or just the opposite if it were
blocked.

Barry


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

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-06-30 19:05
    For faster response and lower sensitivity, use 10K. For slower response
    and higher sensitivity, use 100K. Instead of Radio Shack, you can also
    use Phlmore platic fiber optic photologic detectors, without the plastic
    light pipe. They are TTL/CMOS compatible.

    Dennis

    Original Message
    From: Barry Erick [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=aLJUyvtxEX_psyohKmBFQ5EzlwKa2ZLkZd9BIw96P_uq5RlfwK-WNzY7CIaxichSd7Pm5Hk]berick@e...[/url
    Sent: Tuesday, June 29, 2004 7:05 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] IR PhotoTransistor


    I need to find what RL should be used on a Radio Shack PhotoTransistor
    (NOT THE DECODER, JUST THE PhotoTransistor that comes packaged with a
    LED)

    This could be either as a Common Cathode or Common Anode setup to use
    this as a switch. If connected to P3, for instance, I would have a 1 or
    0 if the LED was passing to the PhotoTransistor or just the opposite if
    it were blocked.

    Barry


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




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  • ArchiverArchiver Posts: 46,084
    edited 2004-06-30 19:44
    Thanks to both you and John. Sorry for the double post. I first thought I
    sent the message last night and when it did not show, I thought maybe it was
    because I did not post it from Yahoo and just my email. So I posted again.
    Then I saw the first message was just stuck in my outgoing mail and was
    never sent until it was too late.
    It turns out my 60 year old eyes misread the resistor I was using and I
    picked a 1.2k instead of a 12k. That fried the phototransistor and my 60
    year old mind also skipped over good old ohms law on the value. Maybe
    because I am on vacation and not doing my main work that I have over 40
    years in that uses ohms law daily.
    Barry


    >
    Original Message
    > From: Dennis O'Leary [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=43epQmD9j0qjps5mM9u7DTlSp9ahtBDb4nNkMPoICF30SbkxoiTl-2IVsgz4G6xrlYngCRhQf6oCKVv_EQ]doleary@e...[/url
    > Sent: Wednesday, June 30, 2004 2:06 PM
    > To: basicstamps@yahoogroups.com
    > Subject: RE: [noparse][[/noparse]basicstamps] IR PhotoTransistor
    >
    > For faster response and lower sensitivity, use 10K. For slower response
    > and higher sensitivity, use 100K. Instead of Radio Shack, you can also
    > use Phlmore platic fiber optic photologic detectors, without the plastic
    > light pipe. They are TTL/CMOS compatible.
    >
    > Dennis
    >
    >
    Original Message
    > From: Barry Erick [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=i76-l4KH0JMe2U5rGSFSyr9JesCiVpfBP55F0VNA2HNwL2ATBffj8K6KXaXqq0wSh44QgRmC]berick@e...[/url
    > Sent: Tuesday, June 29, 2004 7:05 PM
    > To: basicstamps@yahoogroups.com
    > Subject: [noparse][[/noparse]basicstamps] IR PhotoTransistor
    >
    >
    > I need to find what RL should be used on a Radio Shack PhotoTransistor
    > (NOT THE DECODER, JUST THE PhotoTransistor that comes packaged with a
    > LED)
    >
    > This could be either as a Common Cathode or Common Anode setup to use
    > this as a switch. If connected to P3, for instance, I would have a 1 or
    > 0 if the LED was passing to the PhotoTransistor or just the opposite if
    > it were blocked.
    >
    > Barry
    >
    >
    > [noparse][[/noparse]Non-text portions of this message have been removed]
    >
    >
    >
    >
    > 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.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
    >
    >
    >
    >
    >
    > 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.
    >
    > Yahoo! Groups Links
    >
    >
    >
    >
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