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Pocket Watch B — Parallax Forums

Pocket Watch B

ArchiverArchiver Posts: 46,084
edited 2004-02-25 03:02 in General Discussion
>I would like to know if the Pocket Watch B has the ability to run a
longer
>timing sequence than available from the Long Astable Alarm. I need
to turn
>on a recyclable output for more than the 256 minutes. (8hrs. on, 16
off,
>then repeat) I thought about using the Short Astable Alarm set up as
an
>hourly timer and have the Basic Stamp 2 count the transitions. What
is the
>best way to go about this? If the cycle were to come on at 9:00pm
and go off
>at 5:00pm, 7 days per week, what would the code look like? I realize
you
>can't take the time to write specific code, but if you will steer me
to some
>similar examples or the proper direction it will be a big help.
Thank you.
>RC

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 17:47
    Has anyone used the Pocket Watch B in your BS2 projects? I was
    reading the datasheet, and it shows one connected 1-wire to a BS1,
    but has anyone used it on a BS2 (There's probably a N&V Column for
    this question)?

    One other question...What's a good/recommended battery-backup for
    this device for the time?

    Chris
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 18:04
    At 05:47 PM 2/22/04 +0000, Chris Savage wrote:
    >Has anyone used the Pocket Watch B in your BS2 projects? I was
    >reading the datasheet, and it shows one connected 1-wire to a BS1,
    >but has anyone used it on a BS2 (There's probably a N&V Column for
    >this question)?
    >
    >One other question...What's a good/recommended battery-backup for
    >this device for the time?
    >
    >Chris

    Chris -

    Take a looks here at the Solutions Cubed web site for applications notes for
    using the Pocket Watch B on each of the various Stamps:
    http://www.solutionscubed.com/Solutions%20Cubed/PWB2003.htm

    Regards,

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 18:21
    --- Bruce Bates <bvbates@u...> wrote:
    > Chris -
    > Take a looks here at the Solutions Cubed web site
    > for applications notes for using the Pocket Watch B
    > on each of the various Stamps:
    >
    http://www.solutionscubed.com/Solutions%20Cubed/PWB2003.htm

    Thanks Bruce, I did find some code and one more
    datasheet, however, nothing on Battery Backup methods.
    I interested in one of these modules for a home-made
    Smart-Thermostat...Instead of buying one I think I'll
    build one. But all the clock chips I see that are
    easy to connect to the BS2 have no battery backup.
    Parallel BBRTC chips from Dallas have built-In lithium
    batteries, but if I can come up with a simple enough
    serial RTC I will use it.


    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
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  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 19:54
    Hi Chris,

    Battery backup--I think the following would work:

    schottky
    SD103
    Vdd --->]
    o
    PWB Vcc
    |
    ;--->]
    '
    | SD103
    _____
    --- 4.5 to 5 volts
    |
    Vss



    The PWB draws 3.5 milliamps, and there is no super-low power mode as
    far as I know, so the backup battery will have to be hefty enough to
    sustain that drain. It could be 4 niCad cells trickle charged from
    the 5 volt supply, or 3 alkaline cells. I think the PWB is a PIC
    chip that is programmed as a real time clock with all those neat
    features.

    Other serial real time clock chips like the NJU6533 or the DS1302
    take a bit more Stamp programming. But the standby current is ~1
    microamp down to as low as 1.5 volts, so they can be backed up by a
    lithium battery or capacitor.

    -- Tracy




    >--- Bruce Bates <bvbates@u...> wrote:
    >> Chris -
    >> Take a looks here at the Solutions Cubed web site
    >> for applications notes for using the Pocket Watch B
    >> on each of the various Stamps:
    >>
    >http://www.solutionscubed.com/Solutions%20Cubed/PWB2003.htm
    >
    >Thanks Bruce, I did find some code and one more
    >datasheet, however, nothing on Battery Backup methods.
    > I interested in one of these modules for a home-made
    >Smart-Thermostat...Instead of buying one I think I'll
    >build one. But all the clock chips I see that are
    >easy to connect to the BS2 have no battery backup.
    >Parallel BBRTC chips from Dallas have built-In lithium
    >batteries, but if I can come up with a simple enough
    >serial RTC I will use it.
    >
    >
    >=====
    >Chris Savage
    >Knight Designs
    >324 West Main Street
    >Montour Falls, NY 14865
    >(607) 535-6777
    >
    >http://www.knightdesigns.com
    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 19:56
    I believe the Dallas 1302 (or is it 1306)
    chip has provision for battery backup.
    Add a 3-volt coin cell to the right pins,
    and you're good to go. Battery drain
    current is very low also (microamps?)

    I havn't run one until the battery died,
    so I can't give you life figures...

    --- In basicstamps@yahoogroups.com, Chris Savage
    <knight_designs@y...> wrote:
    > --- Bruce Bates <bvbates@u...> wrote:
    > > Chris -
    > > Take a looks here at the Solutions Cubed web site
    > > for applications notes for using the Pocket Watch B
    > > on each of the various Stamps:
    > >
    > http://www.solutionscubed.com/Solutions%20Cubed/PWB2003.htm
    >
    > Thanks Bruce, I did find some code and one more
    > datasheet, however, nothing on Battery Backup methods.
    > I interested in one of these modules for a home-made
    > Smart-Thermostat...Instead of buying one I think I'll
    > build one. But all the clock chips I see that are
    > easy to connect to the BS2 have no battery backup.
    > Parallel BBRTC chips from Dallas have built-In lithium
    > batteries, but if I can come up with a simple enough
    > serial RTC I will use it.
    >
    >
    > =====
    > Chris Savage
    > Knight Designs
    > 324 West Main Street
    > Montour Falls, NY 14865
    > (607) 535-6777
    >
    > http://www.knightdesigns.com
    >
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Mail SpamGuard - Read only the mail you want.
    > http://antispam.yahoo.com/tools
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 20:21
    The DS1307 can be backed-up with a coin cell, but uses an I2C interface
    so it requires a little more code (for non-BS2p Stamps).

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office


    Original Message
    From: Allan Lane [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=GgYYdQp95AVtWqyuggWWfFa6mpeRIGh_nXprHQGXUnwFQ058tu-p64Eo13tth970n443PIADDhV0ZLpDnIiUYHt0n5M]allan.lane@h...[/url
    Sent: Sunday, February 22, 2004 1:56 PM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] Re: Pocket Watch B


    I believe the Dallas 1302 (or is it 1306)
    chip has provision for battery backup.
    Add a 3-volt coin cell to the right pins,
    and you're good to go. Battery drain
    current is very low also (microamps?)

    I havn't run one until the battery died,
    so I can't give you life figures...

    --- In basicstamps@yahoogroups.com, Chris Savage
    <knight_designs@y...> wrote:
    > --- Bruce Bates <bvbates@u...> wrote:
    > > Chris -
    > > Take a looks here at the Solutions Cubed web site
    > > for applications notes for using the Pocket Watch B
    > > on each of the various Stamps:
    > >
    > http://www.solutionscubed.com/Solutions%20Cubed/PWB2003.htm
    >
    > Thanks Bruce, I did find some code and one more
    > datasheet, however, nothing on Battery Backup methods.
    > I interested in one of these modules for a home-made
    > Smart-Thermostat...Instead of buying one I think I'll build one. But
    > all the clock chips I see that are easy to connect to the BS2 have no
    > battery backup. Parallel BBRTC chips from Dallas have built-In lithium
    > batteries, but if I can come up with a simple enough
    > serial RTC I will use it.
    >
    >
    > =====
    > Chris Savage
    > Knight Designs
    > 324 West Main Street
    > Montour Falls, NY 14865
    > (607) 535-6777
    >
    > http://www.knightdesigns.com
    >
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Mail SpamGuard - Read only the mail you want.
    > http://antispam.yahoo.com/tools



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  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 22:10
    --- Tracy Allen <tracy@e...> wrote:
    > Hi Chris,
    > Battery backup--I think the following would work:
    > schottky
    > SD103
    > Vdd --->]
    o
    PWB Vcc
    > |
    > ;--->]
    '
    > | SD103
    > _____
    > --- 4.5 to 5 volts
    > |
    > Vss

    Checking all possibilities for this (Allan and Jon
    also made replies), but if I was to use this, my one
    question is, would a Ni-Cad pack trickle charge in
    this circuit configuration? I am not familiar with
    those diodes having used mostly 1N4XXX series...


    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
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    http://antispam.yahoo.com/tools
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 22:12
    --- Allan Lane <allan.lane@h...> wrote:
    > I believe the Dallas 1302 (or is it 1306)
    > chip has provision for battery backup.
    > Add a 3-volt coin cell to the right pins,
    > and you're good to go. Battery drain
    > current is very low also (microamps?)

    Well, I wouldn't need one to run off battery very
    long...In fact, in the summer the circuit won't even
    be used. It's only for when the main power goes out
    here. I will look up the PDF Datasheets on those
    chips (I think I have a 1302) and the one Jon
    mentioned.



    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
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  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 22:39
    --- Allan Lane <allan.lane@h...> wrote:
    > I believe the Dallas 1302 (or is it 1306)
    > chip has provision for battery backup.
    > Add a 3-volt coin cell to the right pins,
    > and you're good to go. Battery drain
    > current is very low also (microamps?)

    Okay, it looks as though the DS1302 WILL work for me,
    if I can find a battery or supercap to run off the
    trickle-charge circuit. Thing is, it looks like I
    will need to calculate a charge based on a formula
    provided, but I have to look and see where the
    resistor goes. Thanks for the lead, I do have 2
    DS1302 chips as well as the crystals.



    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
    Do you Yahoo!?
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  • ArchiverArchiver Posts: 46,084
    edited 2004-02-22 22:43
    --- Allan Lane <allan.lane@h...> wrote:
    > I believe the Dallas 1302 (or is it 1306)
    > chip has provision for battery backup.
    > Add a 3-volt coin cell to the right pins,
    > and you're good to go. Battery drain
    > current is very low also (microamps?)

    Okay, on my previous message, I hadn't read far enough
    into the DS1302 datasheet...I now see it appears to
    have the diodes and resistors needed for the charging
    circuit internally, they just need to be selected
    according to the charging current required. Which
    means, if I use a SuperCap or Ni-Cad pack, I need to
    know the charge rate.



    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
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  • ArchiverArchiver Posts: 46,084
    edited 2004-02-23 01:45
    If the battery backup is hardly ever used,
    a typical coin cell would be good for 5 years.
    Just a thought, and it would get you away from
    the charging/overcharging/etc. issues.

    Having said that, if you only need power backup,
    a 'super-cap' will probably give you a few weeks --
    but you can't buy a super-cap at the local Walmart,
    where they do have 2032 coin cells.


    --- In basicstamps@yahoogroups.com, Chris Savage
    <knight_designs@y...> wrote:
    > --- Allan Lane <allan.lane@h...> wrote:
    > > I believe the Dallas 1302 (or is it 1306)
    > > chip has provision for battery backup.
    > > Add a 3-volt coin cell to the right pins,
    > > and you're good to go. Battery drain
    > > current is very low also (microamps?)
    >
    > Okay, it looks as though the DS1302 WILL work for me,
    > if I can find a battery or supercap to run off the
    > trickle-charge circuit. Thing is, it looks like I
    > will need to calculate a charge based on a formula
    > provided, but I have to look and see where the
    > resistor goes. Thanks for the lead, I do have 2
    > DS1302 chips as well as the crystals.
    >
    >
    >
    > =====
    > Chris Savage
    > Knight Designs
    > 324 West Main Street
    > Montour Falls, NY 14865
    > (607) 535-6777
    >
    > http://www.knightdesigns.com
    >
    > __________________________________
    > Do you Yahoo!?
    > Yahoo! Mail SpamGuard - Read only the mail you want.
    > http://antispam.yahoo.com/tools
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-24 00:38
    --- Allan Lane <allan.lane@h...> wrote:
    > If the battery backup is hardly ever used,
    > a typical coin cell would be good for 5 years.
    > Just a thought, and it would get you away from
    > the charging/overcharging/etc. issues.
    > Having said that, if you only need power backup,
    > a 'super-cap' will probably give you a few weeks --
    > but you can't buy a super-cap at the local Walmart,
    > where they do have 2032 coin cells.

    Well, if the 2032 coin cell will work with the DS1302,
    I will use it. I stock CR2032 (Duracell) at the shop
    for computer backup batteries.



    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
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  • ArchiverArchiver Posts: 46,084
    edited 2004-02-24 01:45
    Chris,

    Are you looking for absolute minimum power consumption, where every
    microamp counts? If so, read the electrical specifications of the
    DS1302 carefully about standby current in relation to Vcc1 and Vcc2.

    -- used with a lithium coin cell, be sure the trickle charge is
    disabled (trickle charge register=0)

    -- be sure to use the 6 pf crystal specified, and don't allow any
    stray capacitance from your circuit board. These things are touchy
    about that.

    Looking at the pocket watch B, I don't know, there might be some
    undocumented option for a micro power standby mode.

    -- Tracy


    >--- Allan Lane <allan.lane@h...> wrote:
    >> If the battery backup is hardly ever used,
    >> a typical coin cell would be good for 5 years.
    >> Just a thought, and it would get you away from
    >> the charging/overcharging/etc. issues.
    >> Having said that, if you only need power backup,
    >> a 'super-cap' will probably give you a few weeks --
    >> but you can't buy a super-cap at the local Walmart,
    >> where they do have 2032 coin cells.
    >
    >Well, if the 2032 coin cell will work with the DS1302,
    >I will use it. I stock CR2032 (Duracell) at the shop
    >for computer backup batteries.
    >
    >
    >
    >=====
    >Chris Savage
    >Knight Designs
    >324 West Main Street
    >Montour Falls, NY 14865
    >(607) 535-6777
    >
    >http://www.knightdesigns.com
  • ArchiverArchiver Posts: 46,084
    edited 2004-02-25 03:02
    --- Tracy Allen <tracy@e...> wrote:
    > Chris,
    > Are you looking for absolute minimum power
    > consumption, where every
    > microamp counts? If so, read the electrical
    > specifications of the
    > DS1302 carefully about standby current in relation
    > to Vcc1 and Vcc2.

    Tracy, no, this isn't any kind of critical power
    situation. It's merely a programmable thermostat
    using the BS2, and an LCD, but I needed an RTC so I
    could program the schedule, and I wanted minimal
    compensation for power loss, which happens about once
    every 6 to 8 weeks. So, nothing critical...I can
    always verify the RTC when I get home and have to
    reset all the other clocks that are screwed up
    whenever the power goes out.

    > -- used with a lithium coin cell, be sure the
    > trickle charge is
    > disabled (trickle charge register=0)
    > -- be sure to use the 6 pf crystal specified, and
    > don't allow any
    > stray capacitance from your circuit board. These
    > things are touchy
    > about that.

    Thanks for the advice...I'm not sure on the crystals,
    but now that you have mentioned it, I will check
    tomorrow at the shop.


    =====
    Chris Savage
    Knight Designs
    324 West Main Street
    Montour Falls, NY 14865
    (607) 535-6777

    http://www.knightdesigns.com

    __________________________________
    Do you Yahoo!?
    Yahoo! Mail SpamGuard - Read only the mail you want.
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