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Re: [RSSC-list] Battery monitor

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  • Ron Rose
    One alternative for a power FET is a push to latch relay configuration. One side of the coil is connected to the center moving contact which activates the
    Message 1 of 5 , Feb 1, 2009
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      One alternative for a power FET is a push to latch relay
      configuration. One side of the coil is connected to the center moving
      contact which activates the coil when pushed to the make contact which
      is connected to battery. The other end of the coil is connected thru a
      resistor (supplies just enough current to hold the latch) and the
      currect supplying transistor activated by the drop off voltage sense
      circuit. The voltage sense circuit could be a comparator/Op amp
      connected in the wheatstone bridge configuration with the center bridge
      connected to their inputs thru bias resistors. One side is a voltage
      reference from the activated circuits or a resister and zener. The other
      side is a POT that sets the operating drop off voltage. The voltage
      sense can be on the battery or the activated side. A capacitor to the
      center POT contact makes the sense circuit more sensetive to load spikes
      when connected to high and less sensetive when connected to low. A
      battery disconnect switch needs to be included.

      Ron


      ----- Original Message -----
      From: "Alex Brown" <rbirac@...>
      To: <RSSC-list@yahoogroups.com>
      Sent: Friday, January 23, 2009 6:17 PM
      Subject: [RSSC-list] Battery monitor


      > Hey pres,
      >
      > You mentioned you had a circuit to shut down a battery as a result
      of monitoring for a low voltage and drawing no current after the
      shutdown. I'm working aon building a new robot ( Rocky 2 ? ) and am
      planning for the power controller. Do you have any schematic or equiv
      that you could send me or post somewhere?
      >
      > Thanks,
      > Alex
      >
      > !DSPAM:497a7a59860574052115330!
      >
    • Alex Brown
      Ron, Clever setup. But now that I m going with a PICAXE to implement the LED display and the audio chirp, it is easy to also use it to control a relay, if
      Message 2 of 5 , Feb 1, 2009
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        Ron,
         
            Clever setup.  But now that I'm going with a PICAXE to implement the LED display and the audio chirp, it is easy to also use it to control a relay, if required, or the MOSFET.  And I am attracted to the "no moving parts" aspect of the MOSFET as well as the fact that it is likely less expensive than a high amperage relay. 
         
        Alex
         
        ----- Original Message -----
        From: Ron Rose
        Sent: Sunday, February 01, 2009 11:18 AM
        Subject: Re: [RSSC-list] Battery monitor

        One alternative for a power FET is a push to latch relay
        configuration. One side of the coil is connected to the center moving
        contact which activates the coil when pushed to the make contact which
        is connected to battery. The other end of the coil is connected thru a
        resistor (supplies just enough current to hold the latch) and the
        currect supplying transistor activated by the drop off voltage sense
        circuit. The voltage sense circuit could be a comparator/Op amp
        connected in the wheatstone bridge configuration with the center bridge
        connected to their inputs thru bias resistors. One side is a voltage
        reference from the activated circuits or a resister and zener. The other
        side is a POT that sets the operating drop off voltage. The voltage
        sense can be on the battery or the activated side. A capacitor to the
        center POT contact makes the sense circuit more sensetive to load spikes
        when connected to high and less sensetive when connected to low. A
        battery disconnect switch needs to be included.

        Ron

        ----- Original Message -----
        From: "Alex Brown" <rbirac@...>
        To: <RSSC-list@yahoogrou ps.com>
        Sent: Friday, January 23, 2009 6:17 PM
        Subject: [RSSC-list] Battery monitor

        > Hey pres,
        >
        > You mentioned you had a circuit to shut down a battery as a result
        of monitoring for a low voltage and drawing no current after the
        shutdown. I'm working aon building a new robot ( Rocky 2 ? ) and am
        planning for the power controller. Do you have any schematic or equiv
        that you could send me or post somewhere?
        >
        > Thanks,
        > Alex
        >
        > !DSPAM:497a7a598605 74052115330!
        >



        __________ Information from ESET NOD32 Antivirus, version of virus signature database 3816 (20090201) __________

        The message was checked by ESET NOD32 Antivirus.

        http://www.eset.com
      • Ron Rose
        Thinking further, 8 pin DIPs generally contain 2 OP amps. Use one as a comaparator and the other as a astable multivibrator which drives a voltage doubler. The
        Message 3 of 5 , Feb 2, 2009
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          Thinking further, 8 pin DIPs generally contain 2 OP amps. Use one as a
          comaparator and the other as a astable multivibrator which drives a
          voltage doubler. The comparator can probably drive something to activate
          the MOSFET now that double voltage is there. Some comparators come with
          a transistor as their output which require a pullup resistor which can
          be connected to separate voltage.

          Ron

          ----- Original Message -----
          From: "Alex Brown" <rbirac@...>
          To: <RSSC-list@yahoogroups.com>
          Sent: Sunday, February 01, 2009 4:04 PM
          Subject: Re: [RSSC-list] Battery monitor


          > Ron,
          >
          > Clever setup. But now that I'm going with a PICAXE to implement
          the LED display and the audio chirp, it is easy to also use it to
          control a relay, if required, or the MOSFET. And I am attracted to the
          "no moving parts" aspect of the MOSFET as well as the fact that it is
          likely less expensive than a high amperage relay.
          >
          > Alex
          >
          > ----- Original Message -----
          > From: Ron Rose
          > To: RSSC-list@yahoogroups.com
          > Sent: Sunday, February 01, 2009 11:18 AM
          > Subject: Re: [RSSC-list] Battery monitor
          >
          >
          > One alternative for a power FET is a push to latch relay
          > configuration. One side of the coil is connected to the center
          moving
          > contact which activates the coil when pushed to the make contact
          which
          > is connected to battery. The other end of the coil is connected thru
          a
          > resistor (supplies just enough current to hold the latch) and the
          > currect supplying transistor activated by the drop off voltage sense
          > circuit. The voltage sense circuit could be a comparator/Op amp
          > connected in the wheatstone bridge configuration with the center
          bridge
          > connected to their inputs thru bias resistors. One side is a voltage
          > reference from the activated circuits or a resister and zener. The
          other
          > side is a POT that sets the operating drop off voltage. The voltage
          > sense can be on the battery or the activated side. A capacitor to
          the
          > center POT contact makes the sense circuit more sensetive to load
          spikes
          > when connected to high and less sensetive when connected to low. A
          > battery disconnect switch needs to be included.
          >
          > Ron
          >
          > ----- Original Message -----
          > From: "Alex Brown" <rbirac@...>
          > To: <RSSC-list@yahoogroups.com>
          > Sent: Friday, January 23, 2009 6:17 PM
          > Subject: [RSSC-list] Battery monitor
          >
          > > Hey pres,
          > >
          > > You mentioned you had a circuit to shut down a battery as a result
          > of monitoring for a low voltage and drawing no current after the
          > shutdown. I'm working aon building a new robot ( Rocky 2 ? ) and am
          > planning for the power controller. Do you have any schematic or
          equiv
          > that you could send me or post somewhere?
          > >
          > > Thanks,
          > > Alex
          > >
          > >
          > >
          >
          >
          >
          >
          >
          > __________ Information from ESET NOD32 Antivirus, version of virus
          signature database 3816 (20090201) __________
          >
          > The message was checked by ESET NOD32 Antivirus.
          >
          > http://www.eset.com
          >
          >
          > !DSPAM:498638b9861131526718616!
          >
        • Brandt Daniels
          In case any of you are interested, I am here to report that the wireless programming tutorial at sparkfun.com works!
          Message 4 of 5 , Feb 3, 2009
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            In case any of you are interested, I am here to report that the wireless
            programming tutorial at sparkfun.com works!

            http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=122


            I did it last night and it was able to upload my 32KB hex file just
            fine. It uses checksums to make sure the target receives the complete
            payload.

            -Brandt
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