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SPSHV3 issue

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  • jaydmdigital
    I built the SPSH version 3 per the schematic available on the web. In testing it, I am using a 5V supply. The logic of the circuit works (reveres motor
    Message 1 of 10 , Jun 10, 2008
      I built the SPSH version 3 per the schematic available on the web. In
      testing it, I am using a 5V supply. The logic of the circuit works
      (reveres motor direction) but I have no dead band ... it never stops.
      I took a few hours to understand and read Wilf's description and I
      think my issue is that my 1381 switch is the wrong voltage. I ordered
      the C version (2.0V) but in their circuit they used a J (2.7V).

      Also, I'm using the CDS cells from solarbotics if that makes any
      difference. I have checked my wiring/soldering many times. During
      troubleshooting, I replaced the 510K ohm dead band resistor with a 2M
      variable resistor. I practically have the resistance at 0 to get a
      more well behaved transition from one direction to the other, but it
      still never stops.

      Help please,
      Jay
    • wilf_nv
      How massive is the head assembly? ... In ... stops. ... ordered ... 2M
      Message 2 of 10 , Jun 10, 2008
        How massive is the head assembly?


        --- In beam@yahoogroups.com, "jaydmdigital" <jay.couture@...> wrote:
        >
        > I built the SPSH version 3 per the schematic available on the web.
        In
        > testing it, I am using a 5V supply. The logic of the circuit works
        > (reveres motor direction) but I have no dead band ... it never
        stops.
        > I took a few hours to understand and read Wilf's description and I
        > think my issue is that my 1381 switch is the wrong voltage. I
        ordered
        > the C version (2.0V) but in their circuit they used a J (2.7V).
        >
        > Also, I'm using the CDS cells from solarbotics if that makes any
        > difference. I have checked my wiring/soldering many times. During
        > troubleshooting, I replaced the 510K ohm dead band resistor with a
        2M
        > variable resistor. I practically have the resistance at 0 to get a
        > more well behaved transition from one direction to the other, but it
        > still never stops.
        >
        > Help please,
        > Jay
        >
      • jaydmdigital
        At this point, it s all on a proto board (sans the solar cell) and it s not mounted to the motor. I m simply bench testing it. I m never seeing a steady state.
        Message 3 of 10 , Jun 10, 2008
          At this point, it's all on a proto board (sans the solar cell) and
          it's not mounted to the motor. I'm simply bench testing it. I'm never
          seeing a steady state. Also, the higher I make the dead band resistor,
          the less responsive the system is to changes in light. Furthermore, I
          have improved response by shielding the sensors with tubes. So is it
          safe to assume the 1381C devices will work fine?

          Jay

          --- In beam@yahoogroups.com, "wilf_nv" <wrigter@...> wrote:
          >
          > How massive is the head assembly?
          >
          >
        • wilf_nv
          I am glad you are testing this circuit before building it. You learn the most by debugging problems. The PSH design is somewhat counter intuitive: The outputs
          Message 4 of 10 , Jun 10, 2008
            I am glad you are testing this circuit before building it. You learn
            the most by debugging problems. The PSH design is somewhat counter
            intuitive: The outputs are steady state one high and one low with the
            polarity such that the motor turns the sensors towards light source. In
            the power smart mode the head does not move and the circuit uses very
            little current but the outputs are actually oscillating. That is
            because the oscillating voltage signals on the motor terminals are in
            phase (common mode). Check this out by connecting a motor across the
            outputs.

            Once the head circuit is working you can test out the solar engine.
            The 1381C trigger is fine if your gearmotor is a very efficient low
            voltage type. For interest, are you using the SPSH3 schematic?

            Wilf



            --- In beam@yahoogroups.com, "jaydmdigital" <jay.couture@...> wrote:
            >
            > At this point, it's all on a proto board (sans the solar cell) and
            > it's not mounted to the motor. I'm simply bench testing it. I'm never
            > seeing a steady state. Also, the higher I make the dead band resistor,
            > the less responsive the system is to changes in light. Furthermore, I
            > have improved response by shielding the sensors with tubes. So is it
            > safe to assume the 1381C devices will work fine?
            >
            > Jay
            >
            > --- In beam@yahoogroups.com, "wilf_nv" <wrigter@> wrote:
            > >
            > > How massive is the head assembly?
            > >
            > >
            >
          • jaydmdigital
            Yes, at this time, I have the small geared pager motor from Solarbotics connected and I m using my hand to turn the head towards/away from the light to test. I
            Message 5 of 10 , Jun 10, 2008
              Yes, at this time, I have the small geared pager motor from
              Solarbotics connected and I'm using my hand to turn the head
              towards/away from the light to test.

              I amusing the SPSHv3 schematic
              http://www.beam-wiki.org/wiki/index.php?title=Power_Smart_Heads version 3.

              Jay
              --- In beam@yahoogroups.com, "wilf_nv" <wrigter@...> wrote:
              >
              > I am glad you are testing this circuit before building it. You learn
              > the most by debugging problems. The PSH design is somewhat counter
              > intuitive: The outputs are steady state one high and one low with the
              > polarity such that the motor turns the sensors towards light source. In
              > the power smart mode the head does not move and the circuit uses very
              > little current but the outputs are actually oscillating. That is
              > because the oscillating voltage signals on the motor terminals are in
              > phase (common mode). Check this out by connecting a motor across the
              > outputs.
              >
              > Once the head circuit is working you can test out the solar engine.
              > The 1381C trigger is fine if your gearmotor is a very efficient low
              > voltage type. For interest, are you using the SPSH3 schematic?
              >
              > Wilf
              >
              >
              >
              > --- In beam@yahoogroups.com, "jaydmdigital" <jay.couture@> wrote:
              > >
              > > At this point, it's all on a proto board (sans the solar cell) and
              > > it's not mounted to the motor. I'm simply bench testing it. I'm never
              > > seeing a steady state. Also, the higher I make the dead band resistor,
              > > the less responsive the system is to changes in light. Furthermore, I
              > > have improved response by shielding the sensors with tubes. So is it
              > > safe to assume the 1381C devices will work fine?
              > >
              > > Jay
              > >
              > > --- In beam@yahoogroups.com, "wilf_nv" <wrigter@> wrote:
              > > >
              > > > How massive is the head assembly?
              > > >
              > > >
              > >
              >
            • wilf_nv
              Hi Jay, Can disconnect everything but the PSH HEAD section of the circuit and test that subsystem without the SE and standby LED parts? Just connect the LDRs
              Message 6 of 10 , Jun 11, 2008
                Hi Jay,

                Can disconnect everything but the PSH HEAD section of the circuit and
                test that subsystem without the SE and standby LED parts?

                Just connect the LDRs as shown in series across the power supply.
                Disconnect all unused outputs. Connect pin 1, pin 10, and pin 19 to
                0V. Connect all unused inputs to 0V. Then run the test and trim the
                gain resistor for a deadband sufficicnt to accomodate the mechanical
                overshoot after the "brake" is applied. The "braking" occurs when
                both sides of the motor winding have the same polarity squarewave
                applied. Also confirm that you are using a 74HC240 or 74AC240 chip.

                wilf



                --- In beam@yahoogroups.com, "jaydmdigital" <jay.couture@...> wrote:
                >
                > Yes, at this time, I have the small geared pager motor from
                > Solarbotics connected and I'm using my hand to turn the head
                > towards/away from the light to test.
                >
                > I amusing the SPSHv3 schematic
                > http://www.beam-wiki.org/wiki/index.php?title=Power_Smart_Heads
                version 3.
                >
                > Jay
                > --- In beam@yahoogroups.com, "wilf_nv" <wrigter@> wrote:
                > >
                > > I am glad you are testing this circuit before building it. You
                learn
                > > the most by debugging problems. The PSH design is somewhat
                counter
                > > intuitive: The outputs are steady state one high and one low
                with the
                > > polarity such that the motor turns the sensors towards light
                source. In
                > > the power smart mode the head does not move and the circuit uses
                very
                > > little current but the outputs are actually oscillating. That is
                > > because the oscillating voltage signals on the motor terminals
                are in
                > > phase (common mode). Check this out by connecting a motor across
                the
                > > outputs.
                > >
                > > Once the head circuit is working you can test out the solar
                engine.
                > > The 1381C trigger is fine if your gearmotor is a very efficient
                low
                > > voltage type. For interest, are you using the SPSH3 schematic?
                > >
                > > Wilf
                > >
                > >
                > >
                > > --- In beam@yahoogroups.com, "jaydmdigital" <jay.couture@> wrote:
                > > >
                > > > At this point, it's all on a proto board (sans the solar cell)
                and
                > > > it's not mounted to the motor. I'm simply bench testing it. I'm
                never
                > > > seeing a steady state. Also, the higher I make the dead band
                resistor,
                > > > the less responsive the system is to changes in light.
                Furthermore, I
                > > > have improved response by shielding the sensors with tubes. So
                is it
                > > > safe to assume the 1381C devices will work fine?
                > > >
                > > > Jay
                > > >
                > > > --- In beam@yahoogroups.com, "wilf_nv" <wrigter@> wrote:
                > > > >
                > > > > How massive is the head assembly?
                > > > >
                > > > >
                > > >
                > >
                >
              • wilf_nv
                Please explain what you mean by steady state . The effect of raising the dead band resistor on sensitivity is expected. If the LDRs are not mounted on the
                Message 7 of 10 , Jun 11, 2008
                  Please explain what you mean by "steady state". The effect of raising
                  the dead band resistor on sensitivity is expected.

                  If the LDRs are not mounted on the motor the stabilizing servo action
                  can not be observed. Try replacing the two LDRs, which act as a voltage
                  divider with a 100K pot. You should be able to adjust the pot so that
                  the motor stops turning.

                  What chip are you using. The 1381c lowers the trigger voltage but if
                  the motor can handle this lower voltage then that is fine. In that case
                  consider using a lower voltage higher current solar cell and using a
                  single super cap.


                  --- In beam@yahoogroups.com, "jaydmdigital" <jay.couture@...> wrote:
                  >
                  > At this point, it's all on a proto board (sans the solar cell) and
                  > it's not mounted to the motor. I'm simply bench testing it. I'm never
                  > seeing a steady state. Also, the higher I make the dead band resistor,
                  > the less responsive the system is to changes in light. Furthermore, I
                  > have improved response by shielding the sensors with tubes. So is it
                  > safe to assume the 1381C devices will work fine?
                  >
                  > Jay
                  >
                  > --- In beam@yahoogroups.com, "wilf_nv" <wrigter@> wrote:
                  > >
                  > > How massive is the head assembly?
                  > >
                  > >
                  >
                • jaydmdigital
                  Wilf, I will do this and report back. The chips I bought are 74HC240. Now let me go dig out a breadboard :)
                  Message 8 of 10 , Jun 14, 2008
                    Wilf, I will do this and report back. The chips I bought are 74HC240.
                    Now let me go dig out a breadboard :)

                    --- In beam@yahoogroups.com, "wilf_nv" <wrigter@...> wrote:
                    >
                    > Hi Jay,
                    >
                    > Can disconnect everything but the PSH HEAD section of the circuit and
                    > test that subsystem without the SE and standby LED parts?
                    >
                    > Just connect the LDRs as shown in series across the power supply.
                    > Disconnect all unused outputs. Connect pin 1, pin 10, and pin 19 to
                    > 0V. Connect all unused inputs to 0V. Then run the test and trim the
                    > gain resistor for a deadband sufficient to accommodate the mechanical
                    > overshoot after the "brake" is applied. The "braking" occurs when
                    > both sides of the motor winding have the same polarity squarewave
                    > applied. Also confirm that you are using a 74HC240 or 74AC240 chip.
                    >
                    > wilf
                  • jaydmdigital
                    By steady state I mean a point where the output on 7 = the output on 5 and the motor is stopped. I have the eyes mounted to a PCB in a vice with the motor
                    Message 9 of 10 , Jun 14, 2008
                      By steady state I mean a point where the output on 7 = the output on 5
                      and the motor is stopped.

                      I have the "eyes" mounted to a PCB in a vice with the motor connected
                      only to show output (ie turning left, right, or stopped). My
                      understanding is that if both LDRS recieve the same ammount of light
                      (pending how well they are matched) then the voltage would be divided
                      equally. Thus is Vcc is 5V then an input of 2.5V would mean the motor
                      should stop. Any variation from "equal" and the motor will turn.

                      The motor is a geared pager motor (might be too small but we'll see.

                      At this time, the solar cell is sitting on the bench, a 5V switching
                      regulator is "at bat". I am using the 74HC240.

                      Thanks for your feedback I do appreciate your time.
                      Jay

                      --- In beam@yahoogroups.com, "wilf_nv" <wrigter@...> wrote:
                      >
                      > Please explain what you mean by "steady state". The effect of raising
                      > the dead band resistor on sensitivity is expected.
                      >
                      > If the LDRs are not mounted on the motor the stabilizing servo action
                      > can not be observed. Try replacing the two LDRs, which act as a voltage
                      > divider with a 100K pot. You should be able to adjust the pot so that
                      > the motor stops turning.
                      >
                      > What chip are you using. The 1381c lowers the trigger voltage but if
                      > the motor can handle this lower voltage then that is fine. In that case
                      > consider using a lower voltage higher current solar cell and using a
                      > single super cap.
                      >
                    • jaydmdigital
                      Update. I built aother PSH v3 on a breadboard. Following what you said to do I left off the LED circuit and tied all unused inputs to ground. I also did not
                      Message 10 of 10 , Jun 14, 2008
                        Update. I built aother PSH v3 on a breadboard. Following what you said
                        to do I left off the LED circuit and tied all unused inputs to ground.
                        I also did not connect my 1F supercap. It worked perfectly!

                        So I moved it to a protoboard. With the addition of a super cap, it
                        does better than before, but still doesn't stop completely ... it more
                        or less shakes back and forth but I'll take it :)

                        Jay
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