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Ditigal Control of Light — Parallax Forums

Ditigal Control of Light

ArchiverArchiver Posts: 46,084
edited 2001-06-17 00:21 in General Discussion
Anyone have any suggestions on how to control brightness of a 120vac 250
watt lightbulb using a BS1 or 2?

Hey, I know it's probably a dumb question...

Thanks.

Rus

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Comments

  • ArchiverArchiver Posts: 46,084
    edited 2001-06-15 22:00
    Hi,
    You can wire the lamp in series with a triac. This is a bi-directional scr
    device. I would utilize an opto-isolator between the dc output of the stamp,
    and the ac input of the triac. Just make sure the device you choose can
    handle the current of the lamp, and if necessary is adequately heatsunk.

    If you send a pulse stream to the triac gate, the light will come on in
    proportion to the frequency of these pulses.

    good luck

    Russ




    Original Message
    From: Rus Hardy <rushardy@m...>
    To: Stamp Group <basicstamps@yahoogroups.com>
    Sent: Friday, June 15, 2001 4:49 PM
    Subject: [noparse][[/noparse]basicstamps] Ditigal Control of Light


    | Anyone have any suggestions on how to control brightness of a 120vac 250
    | watt lightbulb using a BS1 or 2?
    |
    | Hey, I know it's probably a dumb question...
    |
    | Thanks.
    |
    | Rus
    |
    | --
    | Bones
    | "Ghoul-Will Ambassador to the Boneyard"
    | Atrophies - Ghoulishly Original Awards & Trophies
    | http://www.bluedestiny.com/Atrophies/
    | SpiderBucky & SpiderThrifty - Boney Superheroes
    | http://www.bluedestiny.com/SpiderBucky/
    | Keeper of the Bucky-n-Thrifty Flame
    | http://www.boneyardbargains.com/
    | "my mind wanders....I'm just along for the ride"
    |
    |
    |
    | To UNSUBSCRIBE, just send mail to:
    | basicstamps-unsubscribe@yahoogroups.com
    | from the same email address that you subscribed with. 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 2001-06-15 23:58
    At 5:00 PM -0400 6/15/01, Russ Bassani, you wrote about Re:
    [noparse][[/noparse]basicstamps] Ditigal Control of Light:
    >
    >
    >| Anyone have any suggestions on how to control brightness of a 120vac 250
    >| watt lightbulb using a BS1 or 2?
    >|


    Solid State relays (available from the usual suspects) can send power
    to the lamp with the low voltage signal from the Stamp.

    Varying the output pulse width and/or timing would set the brightness?
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  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 00:14
    If you use a triac, you need to fire the triac at some time referenced to
    the zero crossing of the line. This is phase angle control. Counting zero
    crossings and firing every n crossings can give you some control, but will
    cause flicker if used over the entire range. Using the ability of the Stamp
    to combine both of these (set a delay after zero crossing before firing the
    triac and counting zero crossings) will probably give you the best results.
    Now, all you have to do is get the zero crossing information into the
    Stamp. Running a variable frequency into the gate or turning on an SSR with
    such a signal will vary the output, but not in a continuous way. The 60 hZ
    line will beat with the control signal.
    Isn't this the kind of thing that the X10 folks do all the time? Might be
    something in SmartHouse.com
    Mike


    At 03:49 PM 6/15/2001 -0500, you wrote:
    >Anyone have any suggestions on how to control brightness of a 120vac 250
    >watt lightbulb using a BS1 or 2?
    >
    >Hey, I know it's probably a dumb question...
    >
    >Thanks.
    >
    >Rus

    _________________________________
    Mike Walsh
    walsh@i...
  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 01:51
    You could use triacs and pulse on and off with serout. If your triac
    triggers fast enougn, it ends up looking not like a series of quick
    flashes but as a continuous luminosity.


    On Fri, 15 Jun 2001, Rus Hardy wrote:

    > Anyone have any suggestions on how to control brightness of a 120vac 250
    > watt lightbulb using a BS1 or 2?
    >
    > Hey, I know it's probably a dumb question...
    >
    > Thanks.
    >
    > Rus
    >
    > --
    > Bones
    > "Ghoul-Will Ambassador to the Boneyard"
    > Atrophies - Ghoulishly Original Awards & Trophies
    > http://www.bluedestiny.com/Atrophies/
    > SpiderBucky & SpiderThrifty - Boney Superheroes
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    > Keeper of the Bucky-n-Thrifty Flame
    > http://www.boneyardbargains.com/
    > "my mind wanders....I'm just along for the ride"
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed with. Text in the Subject and
    Body of the message will be ignored.
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    >
    >
    >

    Sean T. Lamont, CTO / Chief NetNerd, Abstract Software, Inc. (ServNet)
    Seattle - Bellingham - Vancouver - Portland - Everett - Tacoma - Bremerton
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  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 03:40
    Rus

    I've used a voltage controlled dimmer kit made by
    Velleman. I control it with a MAX500 DAC (two wire
    serial). Total cost is about $35.00. It does give
    very fine control - 255 steps from off to full bright.
    This frees the stamp for other things except when
    changing the brightness. Jameco sells the Velleman
    kit. Another option is to use a X10 dimmer control -
    I don't have any experience with those, though.

    Lew Muller
    --- Rus Hardy <rushardy@m...> wrote:
    > Anyone have any suggestions on how to control
    > brightness of a 120vac 250
    > watt lightbulb using a BS1 or 2?
    >
    > Hey, I know it's probably a dumb question...
    >
    > Thanks.
    >
    > Rus
    >
    > --
    > Bones
    > "Ghoul-Will Ambassador to the Boneyard"
    > Atrophies - Ghoulishly Original Awards & Trophies
    > http://www.bluedestiny.com/Atrophies/
    > SpiderBucky & SpiderThrifty - Boney Superheroes
    > http://www.bluedestiny.com/SpiderBucky/
    > Keeper of the Bucky-n-Thrifty Flame
    > http://www.boneyardbargains.com/
    > "my mind wanders....I'm just along for the ride"
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed
    > with. 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/
    >
    >


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  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 08:38
    I have read the replies other have sent and they may
    work okay for you. Although you did not state what
    type of light bulb you have. Is the lamp an
    incandescent or is it some type of arc lamp? The arc
    type lamps, such as a metal halide or sodium need a
    ballast and will not start to illuminate without the
    proper starting voltage.

    --- Rus Hardy <rushardy@m...> wrote:
    > Anyone have any suggestions on how to control
    > brightness of a 120vac 250
    > watt lightbulb using a BS1 or 2?
    >
    > Hey, I know it's probably a dumb question...
    >
    > Thanks.
    >
    > Rus
    >
    > --
    > Bones
    > "Ghoul-Will Ambassador to the Boneyard"
    > Atrophies - Ghoulishly Original Awards & Trophies
    > http://www.bluedestiny.com/Atrophies/
    > SpiderBucky & SpiderThrifty - Boney Superheroes
    > http://www.bluedestiny.com/SpiderBucky/
    > Keeper of the Bucky-n-Thrifty Flame
    > http://www.boneyardbargains.com/
    > "my mind wanders....I'm just along for the ride"
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed
    > with. 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/
    >
    >


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  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 08:39
    I have read the replies other have sent and they may
    work okay for you. Although you did not state what
    type of light bulb you have. Is the lamp an
    incandescent or is it some type of arc lamp? The arc
    type lamps, such as a metal halide or sodium need a
    ballast and will not start to illuminate without the
    proper starting voltage.

    --- Rus Hardy <rushardy@m...> wrote:
    > Anyone have any suggestions on how to control
    > brightness of a 120vac 250
    > watt lightbulb using a BS1 or 2?
    >
    > Hey, I know it's probably a dumb question...
    >
    > Thanks.
    >
    > Rus
    >
    > --
    > Bones
    > "Ghoul-Will Ambassador to the Boneyard"
    > Atrophies - Ghoulishly Original Awards & Trophies
    > http://www.bluedestiny.com/Atrophies/
    > SpiderBucky & SpiderThrifty - Boney Superheroes
    > http://www.bluedestiny.com/SpiderBucky/
    > Keeper of the Bucky-n-Thrifty Flame
    > http://www.boneyardbargains.com/
    > "my mind wanders....I'm just along for the ride"
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed
    > with. 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/
    >
    >


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  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 18:15
    > --- Rus Hardy <rushardy@m...> wrote:
    > > Anyone have any suggestions on how to control
    > > brightness of a 120vac 250
    > > watt lightbulb using a BS1 or 2?
    > >
    > > Hey, I know it's probably a dumb question...
    > >
    > > Thanks.
    > >
    > > Rus


    Hi Rus: Haven't had the time to try it but the AN1515 by Motorola uses a 555
    timer which has zero detection; phase control and is optically isolated.

    The circuit shown controls a motor but it should also control an
    incandescent lamp.

    Replacing "VR1" (see page 3 of the AN1515) with a digital pot would perhaps
    allow stamp control with multiple increments. A slow dim or ramp up could be
    achieved by adding a capacitor. This solution may be too labour intensive
    but it seems simple and has the big advantage that it is optically isolated
    from line voltages.

    http://merchant.hibbertco.com/fs22/deact/fs22/pdf-docs/motorola/an1515.rev1.
    pdf

    Good Luck,

    Sean
  • ArchiverArchiver Posts: 46,084
    edited 2001-06-16 22:49
    [font=arial,helvetica]

    ··w

    hat is a triac actually?


    [/font]
  • ArchiverArchiver Posts: 46,084
    edited 2001-06-17 00:21

    Original Message
    From: "Sean Gibson" <seangib@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Saturday, June 16, 2001 1:15 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Ditigal Control of Light


    >
    > > --- Rus Hardy <rushardy@m...> wrote:
    > > > Anyone have any suggestions on how to control
    > > > brightness of a 120vac 250
    > > > watt lightbulb using a BS1 or 2?
    > > >
    > > > Hey, I know it's probably a dumb question...
    > > >
    > > > Thanks.
    > > >
    > > > Rus
    >
    >
    > Hi Rus: Haven't had the time to try it but the AN1515 by Motorola uses a
    555
    > timer which has zero detection; phase control and is optically isolated.
    >
    > The circuit shown controls a motor but it should also control an
    > incandescent lamp.
    >
    > Replacing "VR1" (see page 3 of the AN1515) with a digital pot would
    perhaps
    > allow stamp control with multiple increments. A slow dim or ramp up could
    be
    > achieved by adding a capacitor. This solution may be too labour intensive
    > but it seems simple and has the big advantage that it is optically
    isolated
    > from line voltages.
    >
    > Sorry, the correct URL is http://appnote.stts.edu/Motorola/sudah.htm
    >
    > Good Luck,
    >
    > Sean
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed with. 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/
    >
    >
    >
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