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Re: SPSH not leaking any more

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  • wilf_nv
    Hi Steve, Compare the resistance of a BG micro motor (about 50 ohms) with your micro pager motor which has a winding resistance of 11 ohms. 74 HC240 outputs
    Message 1 of 7 , Jul 14, 2002
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      Hi Steve,

      Compare the resistance of a BG micro motor (about 50 ohms) with your
      micro pager motor which has a winding resistance of 11 ohms. 74 HC240
      outputs have an output resistance of about 40 ohms. That tells you
      that with an initial 11 ohm load, there will be a significant voltage
      drop on the 74HC240 motor driver outputs and starting torque will be
      low. Still that pager motor is very efficient, the mechanical load is
      small and once the motor rotates, the effective winding resistance
      goes way up and the driver efficiency increases.

      I saw no specs in the link you gave for the FLED. I checked some RS
      FLEDs I have and the average current is about 2 ma. I designed a new
      74HC240 LED flasher circuit which has an average current of about 100
      uA. The LED flashes much brighter than the FLEDs. The circuit
      provides some voltage boost so it works down to 1.5V. I have posted
      the new SPSH3 circuit in the file section. The low power LED flasher
      comes on when the SE triggers and stays on until the SE resets. The
      rest of the SPSH layout has been changed somewhat to simplify
      connections between IC pins. A layout drawing will follow soon. A
      SPSH4 design is next that replaces the 1381 with two transistors and
      provides dual motor drivers.

      wilf

      --- In beam@y..., "shenri" <shenri@y...> wrote:
      > Yeah the motor runs just fine with only one inverter. I thought
      > about using the extra inverters to make my own fled circuit but I
      > don't know how at this time. My brain has to forget a lot of other
      > stuff before it can absorb anymore of this circuit stuff. :-)
      Right
      > now it's full of other important stuff relating to my career in
      > Oracle DBMS and Networking.
      >
      > Anyway, I'm using 1 diode in series with a 1381J. I don't know how
      > efficient this motor is. Can you tell me?
      > http://sales.goldmine-elec.com/prodinfo.asp?prodid=4089
      >
      > It is hooked up to the last gear on a salvaged oven-timer-unit gear
      > set. I lined up the motor with the gear shaft and put a little
      > silicone caulk between the two shafts to connect them togther.
      What
      > about the FLED I am using, is it a power hog or what.
      >
      > Steve.
      >
    • shenri
      Thanks Wilf for the True Blinking LED SPSH circuit (i.e. SPSH V3). The SPSH v2 with the fled is pretty dim when it does flash and does not draw very much
      Message 2 of 7 , Jul 18, 2002
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        Thanks Wilf for the "True Blinking LED SPSH" circuit (i.e. SPSH V3).
        The SPSH v2 with the fled is pretty dim when it does flash and does
        not draw very much attention from a casual viewer. I'm glad the v3
        circuit addresses this problem. I'll let you know how the v3 head
        works (blinks) when I have a chance to modify my v2 head next week.
        I can't wait to try the v4 circuit you have on the drawing board.

        Look at that. Every sentence starts with a capital letter and ends
        with a period. Amazing.

        Steve.

        --- In beam@y..., "wilf_nv" <wrigter@b...> wrote:
        > Hi Steve,
        >
        > Compare the resistance of a BG micro motor (about 50 ohms) with
        your
        > micro pager motor which has a winding resistance of 11 ohms. 74
        HC240
        > outputs have an output resistance of about 40 ohms. That tells you
        > that with an initial 11 ohm load, there will be a significant
        voltage
        > drop on the 74HC240 motor driver outputs and starting torque will
        be
        > low. Still that pager motor is very efficient, the mechanical load
        is
        > small and once the motor rotates, the effective winding resistance
        > goes way up and the driver efficiency increases.
        >
        > I saw no specs in the link you gave for the FLED. I checked some
        RS
        > FLEDs I have and the average current is about 2 ma. I designed a
        new
        > 74HC240 LED flasher circuit which has an average current of about
        100
        > uA. The LED flashes much brighter than the FLEDs. The circuit
        > provides some voltage boost so it works down to 1.5V. I have
        posted
        > the new SPSH3 circuit in the file section. The low power LED
        flasher
        > comes on when the SE triggers and stays on until the SE resets.
        The
        > rest of the SPSH layout has been changed somewhat to simplify
        > connections between IC pins. A layout drawing will follow soon. A
        > SPSH4 design is next that replaces the 1381 with two transistors
        and
        > provides dual motor drivers.
        >
        > wilf
        >
        > --- In beam@y..., "shenri" <shenri@y...> wrote:
        > > Yeah the motor runs just fine with only one inverter. I thought
        > > about using the extra inverters to make my own fled circuit but
        I
        > > don't know how at this time. My brain has to forget a lot of
        other
        > > stuff before it can absorb anymore of this circuit stuff. :-)
        > Right
        > > now it's full of other important stuff relating to my career in
        > > Oracle DBMS and Networking.
        > >
        > > Anyway, I'm using 1 diode in series with a 1381J. I don't know
        how
        > > efficient this motor is. Can you tell me?
        > > http://sales.goldmine-elec.com/prodinfo.asp?prodid=4089
        > >
        > > It is hooked up to the last gear on a salvaged oven-timer-unit
        gear
        > > set. I lined up the motor with the gear shaft and put a little
        > > silicone caulk between the two shafts to connect them togther.
        > What
        > > about the FLED I am using, is it a power hog or what.
        > >
        > > Steve.
        > >
      • shenri
        Hi Wilf, I built your SPSH3 circuit and am having some problems with it. 1. It will only charge to 3.38V with the solar panels. 2. If I charge the Cap up to
        Message 3 of 7 , Jul 25, 2002
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          Hi Wilf, I built your SPSH3 circuit and am having some problems with
          it.

          1. It will only charge to 3.38V with the solar panels.

          2. If I charge the Cap up to 5 volts with a battery the head works
          as expected. It locks on to the light but then very very quickly
          drains down to 3.38V. On the way down the motor is audible (starts
          to squeel) between 3.6 and 3.4 volts even thought the head is locked
          on to the light.

          3. The LED starts to flash way before the head becomes enabled.

          Do you think it is my wiring or something else?

          Steve.

          --- In beam@y..., "wilf_nv" <wrigter@b...> wrote:
          > Hi Steve,
          >
          I designed a new
          > 74HC240 LED flasher circuit which has an average current of about
          100
          > uA. The LED flashes much brighter than the FLEDs. The circuit
          > provides some voltage boost so it works down to 1.5V. I have
          posted
          > the new SPSH3 circuit in the file section. The low power LED
          flasher
          > comes on when the SE triggers and stays on until the SE resets. The
          > rest of the SPSH layout has been changed somewhat to simplify
          > connections between IC pins. A layout drawing will follow soon. A
          > SPSH4 design is next that replaces the 1381 with two transistors
          and
          > provides dual motor drivers.
          >
          > wilf
        • shenri
          Hi, disregard my last message. I missed one solder connection but it must have been an important one. The head works perfectly now. Ready for that SPSH4
          Message 4 of 7 , Jul 25, 2002
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            Hi, disregard my last message. I missed one solder connection but it
            must have been an important one. The head works perfectly now.
            Ready for that SPSH4 circuit you mentioned a while back.

            Steve.


            --- In beam@y..., "shenri" <shenri@y...> wrote:
            > Hi Wilf, I built your SPSH3 circuit and am having some problems
            with
            > it.
            >
            > 1. It will only charge to 3.38V with the solar panels.
            >
            > 2. If I charge the Cap up to 5 volts with a battery the head works
            > as expected. It locks on to the light but then very very quickly
            > drains down to 3.38V. On the way down the motor is audible (starts
            > to squeel) between 3.6 and 3.4 volts even thought the head is
            locked
            > on to the light.
            >
            > 3. The LED starts to flash way before the head becomes enabled.
            >
            > Do you think it is my wiring or something else?
            >
            > Steve.
            >
            > --- In beam@y..., "wilf_nv" <wrigter@b...> wrote:
            > > Hi Steve,
            > >
            > I designed a new
            > > 74HC240 LED flasher circuit which has an average current of about
            > 100
            > > uA. The LED flashes much brighter than the FLEDs. The circuit
            > > provides some voltage boost so it works down to 1.5V. I have
            > posted
            > > the new SPSH3 circuit in the file section. The low power LED
            > flasher
            > > comes on when the SE triggers and stays on until the SE resets.
            The
            > > rest of the SPSH layout has been changed somewhat to simplify
            > > connections between IC pins. A layout drawing will follow soon. A
            > > SPSH4 design is next that replaces the 1381 with two transistors
            > and
            > > provides dual motor drivers.
            > >
            > > wilf
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