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Analog Output from the BS2 — Parallax Forums

Analog Output from the BS2

ArchiverArchiver Posts: 46,084
edited 2003-12-21 01:36 in General Discussion
I am currently looking into a BASIC Stamp powered school project in which I will
have
6 circuits of LEDs which I need to be able to control the voltage of
individually and
simultaneously.

I have looked into various methods of analog output like Digital Potentiometers,

Motor Controllers and PWM+Capacitors, But I am still unsure of the best option,
or if
there are possibilities I am overlooking.

I will need a voltage range of 0v to +5v

Does anyone have suggestions for the most cost effective and beginner-friendly
way
of achieving this? Any help would be very appreciated.

Andrew

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-12-20 18:34
    You could use the Stamp's PWM function to generate an analog output
    through an RC circuit (that what it's designed to do) but you'll have to
    buffer the RC with an opamp. Easier, probably, would be Al Williams'
    [noparse][[/noparse]no relation] multi-channel PWM controller (PAK5). It's a preprogrammed
    SX that lets you PWM up to eight channels. You can use the PWM output
    to control the brightness of your LEDs. The interface between the Stamp
    and the controller is serial (SEROUT) so the programming will be pretty
    straighforward, and the PWM frequency will be maintained in the external
    controller freeing the Stamp for other activities.

    Here's a link:

    http://www.al-williams.com/pak5.htm

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office
    -- (972) 659-9090



    Original Message
    From: iamthesquidthing [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=HdA69HdlOm6q32SQgx87hEufb6DgbuRxxWagY3rx-f5A_ryxD1JlyTVJeuzCOxTFnN9_WxyCg3H4IgWlUfO-]squidthing@x...[/url
    Sent: Saturday, December 20, 2003 6:55 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Analog Output from the BS2


    I am currently looking into a BASIC Stamp powered school project in
    which I will have
    6 circuits of LEDs which I need to be able to control the voltage of
    individually and
    simultaneously.

    I have looked into various methods of analog output like Digital
    Potentiometers,
    Motor Controllers and PWM+Capacitors, But I am still unsure of the best
    option, or if
    there are possibilities I am overlooking.

    I will need a voltage range of 0v to +5v

    Does anyone have suggestions for the most cost effective and
    beginner-friendly way
    of achieving this? Any help would be very appreciated.

    Andrew



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  • ArchiverArchiver Posts: 46,084
    edited 2003-12-21 00:14
    Hi Andrew,
    I use a digital pot for this type of application. It is a nice clean signal
    and easy to do in the stamp. I use Analog Devices AD 7376. It has a serial (3
    Wire) interface, and as long as the rate that you are varying the voltage level
    is not too fast for the pot, you will have good luck.
    I use the digital pot to vary the output of a LM555 timer to run stepper
    motors from the stamp. The stamp cannot directly output pulses fast enough to
    microstep a stepper so I use this poor mans pulse "Turbocharger."

    Samples of the software are on the Parallax site.

    Thanks,
    Alan Bradford
    Plasma Technologies

    I am currently looking into a BASIC Stamp powered school project in which I
    will have
    6 circuits of LEDs which I need to be able to control the voltage of
    individually and
    simultaneously.

    I have looked into various methods of analog output like Digital
    Potentiometers,
    Motor Controllers and PWM+Capacitors, But I am still unsure of the best
    option, or if
    there are possibilities I am overlooking.

    I will need a voltage range of 0v to +5v

    Does anyone have suggestions for the most cost effective and
    beginner-friendly way
    of achieving this? Any help would be very appreciated.

    Andrew


    [noparse][[/noparse]Non-text portions of this message have been removed]
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-21 00:24
    Obviously, I like the PAK-V answer from Jon. However, if you are interested
    in digital pots, I did a set of app notes for Catalyst about using their
    digital pots with the Basic Stamp.

    http://www.catsemi.com/documents/dpp_parallax_booklet.pdf

    Note that some of these devices were not necessarily the best possible
    Catalyst part to interface with a Stamp, but we wanted to show how to use
    the different interfaces.

    Al Williams
    AWC
    * New 3.3 and 5V Power Supply Kits
    http://www.al-williams.com/ps1.htm


    >
    Original Message
    > From: plasmastamp@a... [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=x_I9A_X8Ko7gXDp0B8hIBssp7SC9pk-7fLv4D2M_e6urqIdLvL_Zgx0636qG67Fd0C8vvkYy_6nJaFkzVGM]plasmastamp@a...[/url
    > Sent: Saturday, December 20, 2003 6:14 PM
    > To: basicstamps@yahoogroups.com
    > Subject: Re: [noparse][[/noparse]basicstamps] Analog Output from the BS2
    >
    >
    >
    > Hi Andrew,
    > I use a digital pot for this type of application. It is a
    > nice clean signal
    > and easy to do in the stamp. I use Analog Devices AD 7376. It
    > has a serial (3
    > Wire) interface, and as long as the rate that you are varying
    > the voltage level
    > is not too fast for the pot, you will have good luck.
    > I use the digital pot to vary the output of a LM555 timer to
    > run stepper
    > motors from the stamp. The stamp cannot directly output
    > pulses fast enough to
    > microstep a stepper so I use this poor mans pulse "Turbocharger."
    >
    > Samples of the software are on the Parallax site.
    >
    > Thanks,
    > Alan Bradford
    > Plasma Technologies
    >
    > I am currently looking into a BASIC Stamp powered school
    > project in which I
    > will have
    > 6 circuits of LEDs which I need to be able to control the voltage of
    > individually and
    > simultaneously.
    >
    > I have looked into various methods of analog output like Digital
    > Potentiometers,
    > Motor Controllers and PWM+Capacitors, But I am still unsure
    > of the best
    > option, or if
    > there are possibilities I am overlooking.
    >
    > I will need a voltage range of 0v to +5v
    >
    > Does anyone have suggestions for the most cost effective and
    > beginner-friendly way
    > of achieving this? Any help would be very appreciated.
    >
    > Andrew
    >
    >
    > [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 visit your group on the web, go to:
    > http://groups.yahoo.com/group/basicstamps/
    >
    > To unsubscribe from this group, send an email to:
    > basicstamps-unsubscribe@yahoogroups.com
    >
    > Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/
  • ArchiverArchiver Posts: 46,084
    edited 2003-12-21 01:36
    I definietly recommend the PAK V's. I use them quite a bit for my
    lighting projects and they are the best cost vs. complexity setup.
    They are easy to setup and easy to program. I've used them with
    Pics, OOpics, Stamps, and Atom Pro's and they work pretty slick. I
    recently changed out my old OOpic controller on one of my jets and
    replaced it with a 2SX/AtomPro and a Pak V
    (http://www.rescyou.com/motojet/) and it works awesome for
    controlling fuel injectors and other gizmos.

    The most cost effective route would be a 2 channel digipot but the
    complexity level in programming and setup greatly increase. I use
    Microchip 2 channel, 255 level, 100k pots and they run about $2.50US
    at Digikey.

    The Pak V is the best way to go in my opinion. Shipping is quick,
    email support is great and there is a low parts count. I'm running 6
    luxeon star superleds through one at the moment and it is a sight to
    see.

    Resc.




    --- In basicstamps@yahoogroups.com, "Al Williams" <alw@a...> wrote:
    > Obviously, I like the PAK-V answer from Jon. However, if you are
    interested
    > in digital pots, I did a set of app notes for Catalyst about using
    their
    > digital pots with the Basic Stamp.
    >
    > http://www.catsemi.com/documents/dpp_parallax_booklet.pdf
    >
    > Note that some of these devices were not necessarily the best
    possible
    > Catalyst part to interface with a Stamp, but we wanted to show how
    to use
    > the different interfaces.
    >
    > Al Williams
    > AWC
    > * New 3.3 and 5V Power Supply Kits
    > http://www.al-williams.com/ps1.htm
    >
    >
    > >
    Original Message
    > > From: plasmastamp@a... [noparse][[/noparse]mailto[noparse]:p[/noparse]lasmastamp@a...]
    > > Sent: Saturday, December 20, 2003 6:14 PM
    > > To: basicstamps@yahoogroups.com
    > > Subject: Re: [noparse][[/noparse]basicstamps] Analog Output from the BS2
    > >
    > >
    > >
    > > Hi Andrew,
    > > I use a digital pot for this type of application. It is a
    > > nice clean signal
    > > and easy to do in the stamp. I use Analog Devices AD 7376. It
    > > has a serial (3
    > > Wire) interface, and as long as the rate that you are varying
    > > the voltage level
    > > is not too fast for the pot, you will have good luck.
    > > I use the digital pot to vary the output of a LM555 timer to
    > > run stepper
    > > motors from the stamp. The stamp cannot directly output
    > > pulses fast enough to
    > > microstep a stepper so I use this poor mans pulse "Turbocharger."
    > >
    > > Samples of the software are on the Parallax site.
    > >
    > > Thanks,
    > > Alan Bradford
    > > Plasma Technologies
    > >
    > > I am currently looking into a BASIC Stamp powered school
    > > project in which I
    > > will have
    > > 6 circuits of LEDs which I need to be able to control the
    voltage of
    > > individually and
    > > simultaneously.
    > >
    > > I have looked into various methods of analog output like Digital
    > > Potentiometers,
    > > Motor Controllers and PWM+Capacitors, But I am still unsure
    > > of the best
    > > option, or if
    > > there are possibilities I am overlooking.
    > >
    > > I will need a voltage range of 0v to +5v
    > >
    > > Does anyone have suggestions for the most cost effective and
    > > beginner-friendly way
    > > of achieving this? Any help would be very appreciated.
    > >
    > > Andrew
    > >
    > >
    > > [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 visit your group on the web, go to:
    > > http://groups.yahoo.com/group/basicstamps/
    > >
    > > To unsubscribe from this group, send an email to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > >
    > > Your use of Yahoo! Groups is subject to:
    > http://docs.yahoo.com/info/terms/
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