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usb power? (on mac) — Parallax Forums

usb power? (on mac)

ArchiverArchiver Posts: 46,084
edited 2004-06-14 14:27 in General Discussion
hey all,

does anyone know if you could set up a stamp to use power from the usb
jack instead of a 9 volt on a mac? anyone tried this?

thanks,

matt

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-06-14 11:14
    I think that it is 5V, 500mA max.
    Cut the cable open.
    The two biggest wires are the power supply.
    I have one where Red = + and Black = -
    Regards
    ECO
    Original Message
    From: "Trygve Henriksen" <trygve.henriksen@v...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, June 14, 2004 11:05 AM
    Subject: SV: [noparse][[/noparse]basicstamps] usb power? (on mac)


    > Greetings!
    >
    > Yes it should be doable.
    > I don't remember which pin is what, but one of the pins is Gnd, and
    > another is +12V
    > So get a cable, cut it open and measure.
    > Then add a decent 5V regulator (A 7805 and couple of caps) and you
    > should be all set.
    >
    > As a matter of fact, some people mount relays on this connector, to
    > switch on/off their monitors as this pin gets power as soon as you
    > switch the computer on.
    >
    > :-)
    > Trygve
    >
    >
    >
    Opprinnelig melding
    > Fra: Matt Gilbert [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=VAYovUPJuTfXnamDHzw0vCJb_nYQauWVDiwG-iIrAbOQFfZyGQBS88Lv3nv6irg1k8kLGLiARDiQxZI]gilb_jm@y...[/url
    > Sendt: 13. juni 2004 19:05
    > Til: basicstamps@yahoogroups.com
    > Emne: [noparse][[/noparse]basicstamps] usb power? (on mac)
    >
    >
    > hey all,
    >
    > does anyone know if you could set up a stamp to use power from the usb
    > jack instead of a 9 volt on a mac? anyone tried this?
    >
    > thanks,
    >
    > matt
    >
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
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    > and Body of the message will be ignored.
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  • ArchiverArchiver Posts: 46,084
    edited 2004-06-14 12:04
    I think that it is 5V, 500mA max.
    Cut the cable open.
    The two biggest wires are the power supply.
    I have one where Red = + and Black = -
    Regards
    ECO

    Original Message
    From: "Trygve Henriksen" <trygve.henriksen@v...>
    To: <basicstamps@yahoogroups.com>
    Sent: Monday, June 14, 2004 11:05 AM
    Subject: SV: [noparse][[/noparse]basicstamps] usb power? (on mac)


    > Greetings!
    >
    > Yes it should be doable.
    > I don't remember which pin is what, but one of the pins is Gnd, and
    > another is +12V
    > So get a cable, cut it open and measure.
    > Then add a decent 5V regulator (A 7805 and couple of caps) and you
    > should be all set.
    >
    > As a matter of fact, some people mount relays on this connector, to
    > switch on/off their monitors as this pin gets power as soon as you
    > switch the computer on.
    >
    > :-)
    > Trygve
    >
    >
    >
    Opprinnelig melding
    > Fra: Matt Gilbert [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=Z2frZazfJ2J3v9QskFK8rYlBGT1kOXJRm5QSs9VzNzlnkcOGQgV0TOCM5Fx6T_7wr-xoKsFzm9w]gilb_jm@y...[/url
    > Sendt: 13. juni 2004 19:05
    > Til: basicstamps@yahoogroups.com
    > Emne: [noparse][[/noparse]basicstamps] usb power? (on mac)
    >
    >
    > hey all,
    >
    > does anyone know if you could set up a stamp to use power from the usb
    > jack instead of a 9 volt on a mac? anyone tried this?
    >
    > thanks,
    >
    > matt
    >
    >
    >
    >
    >
    > 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
    >
    >
    >
    >
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-06-14 13:43
    I don't know about the mac, but I do this all the time on the PC. However,
    the power is +5V, not +12V. Every cable I've ever cut has red for +5 and
    black for ground and I solder a 2 pin female header on it and that's 5V.

    Regards,

    Al Williams
    AWC
    *Easy RS232 Prototyping
    http:/www.awce.com/rs1.htm



    Original Message
    From: Trygve Henriksen [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RbPU_3Els9xSg6dJSHDunpenphI0C4vPNI26_1kPtrZq6x4ECj0BaJGxKziTY9pWzIouZ-eOTyftCg-tbv7hbWtAc4s]trygve.henriksen@v...[/url
    Sent: Monday, June 14, 2004 4:05 AM
    To: basicstamps@yahoogroups.com
    Subject: SV: [noparse][[/noparse]basicstamps] usb power? (on mac)


    Greetings!

    Yes it should be doable.
    I don't remember which pin is what, but one of the pins is Gnd, and another
    is +12V So get a cable, cut it open and measure. Then add a decent 5V
    regulator (A 7805 and couple of caps) and you should be all set.

    As a matter of fact, some people mount relays on this connector, to switch
    on/off their monitors as this pin gets power as soon as you switch the
    computer on.

    :-)
    Trygve

    Opprinnelig melding
    Fra: Matt Gilbert [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RpXYfgGTndAtcQi6djQRJS6Cf0c9GW1dS5d6jHWALtz0czA7ZmuLS_aOWDsyrzDUtfJGTx4tGdHCO2i5]gilb_jm@y...[/url
    Sendt: 13. juni 2004 19:05
    Til: basicstamps@yahoogroups.com
    Emne: [noparse][[/noparse]basicstamps] usb power? (on mac)


    hey all,

    does anyone know if you could set up a stamp to use power from the usb
    jack instead of a 9 volt on a mac? anyone tried this?

    thanks,

    matt





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  • ArchiverArchiver Posts: 46,084
    edited 2004-06-14 14:27
    --- In basicstamps@yahoogroups.com, "Al Williams" <alw@a...> wrote:
    > I don't know about the mac, but I do this all the time on the PC.
    However,
    > the power is +5V, not +12V. Every cable I've ever cut has red for
    +5 and
    > black for ground and I solder a 2 pin female header on it and
    that's 5V.
    >
    > Regards,
    >
    > Al Williams
    > AWC
    > *Easy RS232 Prototyping
    > http:/www.awce.com/rs1.htm

    The thing I mentioned last week is that the USB will deliver power
    and it will drop voltage as you increase your load. Laptops will
    offer a much weaker maximum ouput that a desk Mac.

    Figure out your needs, connect a load and watch the voltage drop. as
    you increase your load to some value, you'll see a voltage drop and
    you'll know you have reached the limit for that machine.

    Dave
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