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how to beacon one last time.

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  • Wes Johnston, AI4PX
    I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks at a time. I d like to put a tracker on it that has absolutely 0 current draw
    Message 1 of 9 , Jun 8, 2011
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      I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks at a time.  I'd like to put a tracker on it that has absolutely 0 current draw when off.  Yes, I know I could program the T2 to not transmit if the voltage is below 13.0, but it still has to draw power to check the battery.  What I'd like to do is have it automatically come on and after the ATV is parked tx one last time and go to a zero power state.
       
      To this end, I've thought about a latched relay that gets interupted by the PTT, but it would just stay on until the moment PTT was asserted and turn off just as the packet started to tx.  Probably the best solution is to have a relay unlatch on the rising edge of PTT.
       
      I've also thought about putting the GPS on switched power (ignition switch) and the T2 tied to the battery and just telling it to not tx on no fix.... but would it TX that one last time?  I think not.
       
      An old school solution would be to have a clock mechanism wind a timer and the timer would switch off after a while.... like those single gang windup timers at lowes.
       
      At one time, I did use an RV break away emergency brake switch under a trailer attached to a stake in the yard, but that won't fill the bill this time round.
       
      Any suggestions?

      Wes
      ---
      The world needs more geniuses with humility because there are so few of us left.

    • Fred Hillhouse
      It is possible to use a timer circuit to energize on ATV power up and then hold the power for a period of time after it is shut off. This way it is only on
      Message 2 of 9 , Jun 8, 2011
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        It is possible to use a timer circuit to energize on ATV power up and then hold the power for a period of time after it is shut off. This way it is only on while the ATV is in use and for a short time following. I don't have a circuit handy but it can be done. Relay logic comes to mind in this case. I could sketch and send a PDF it out but it couldn't be for a few days.
         
        Best regards,
        Fred
         
         

        From: tracker2@yahoogroups.com [mailto:tracker2@yahoogroups.com] On Behalf Of Wes Johnston, AI4PX
        Sent: Wednesday, June 08, 2011 13:50
        To: tracker2
        Subject: [tracker2] how to beacon one last time.

         

        I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks at a time.  I'd like to put a tracker on it that has absolutely 0 current draw when off.  Yes, I know I could program the T2 to not transmit if the voltage is below 13.0, but it still has to draw power to check the battery.  What I'd like to do is have it automatically come on and after the ATV is parked tx one last time and go to a zero power state.
         
        To this end, I've thought about a latched relay that gets interupted by the PTT, but it would just stay on until the moment PTT was asserted and turn off just as the packet started to tx.  Probably the best solution is to have a relay unlatch on the rising edge of PTT.
         
        I've also thought about putting the GPS on switched power (ignition switch) and the T2 tied to the battery and just telling it to not tx on no fix.... but would it TX that one last time?  I think not.
         
        An old school solution would be to have a clock mechanism wind a timer and the timer would switch off after a while.... like those single gang windup timers at lowes.
         
        At one time, I did use an RV break away emergency brake switch under a trailer attached to a stake in the yard, but that won't fill the bill this time round.
         
        Any suggestions?

        Wes
        ---
        The world needs more geniuses with humility because there are so few of us left.

      • James Ewen
        A ChargeGuard, or an APO from APRS World would do the job. You would have to put an external relay on it to disconnect completely from the ATV power supply
        Message 3 of 9 , Jun 8, 2011
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          A ChargeGuard, or an APO from APRS World would do the job. You would
          have to put an external relay on it to disconnect completely from the
          ATV power supply though as both devices remain active sensing input
          power. Have the relay set up to provide power to the ChargeGuard from
          the ATV battery. The relay would need to have 2 sense circuits, one
          from accessory power from the ATV, and a second from the output of the
          ChargeGuard, with diode isolation. When the ATV accessory power comes
          up, the relay engages, powering the ChargeGuard. When the ATV shuts
          off and accessory power goes away, the sense line from the output of
          the ChargeGuard keeps the relay active. When the ChargeGuard timer
          runs out, and the ouput gets shut off, the second sense circuit
          holding the relay drops, opening the relay, and removing the
          ChargeGuard from the battery on the ATV.



          On 6/8/11, Fred Hillhouse <fmhillhouse@...> wrote:
          > It is possible to use a timer circuit to energize on ATV power up and then
          > hold the power for a period of time after it is shut off. This way it is
          > only on while the ATV is in use and for a short time following. I don't have
          > a circuit handy but it can be done. Relay logic comes to mind in this case.
          > I could sketch and send a PDF it out but it couldn't be for a few days.
          >
          > Best regards,
          > Fred
          >
          >
          > _____
          >
          > From: tracker2@yahoogroups.com [mailto:tracker2@yahoogroups.com] On Behalf
          > Of Wes Johnston, AI4PX
          > Sent: Wednesday, June 08, 2011 13:50
          > To: tracker2
          > Subject: [tracker2] how to beacon one last time.
          >
          >
          >
          >
          >
          > I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks
          > at a time. I'd like to put a tracker on it that has absolutely 0 current
          > draw when off. Yes, I know I could program the T2 to not transmit if the
          > voltage is below 13.0, but it still has to draw power to check the battery.
          > What I'd like to do is have it automatically come on and after the ATV is
          > parked tx one last time and go to a zero power state.
          >
          > To this end, I've thought about a latched relay that gets interupted by the
          > PTT, but it would just stay on until the moment PTT was asserted and turn
          > off just as the packet started to tx. Probably the best solution is to have
          > a relay unlatch on the rising edge of PTT.
          >
          > I've also thought about putting the GPS on switched power (ignition switch)
          > and the T2 tied to the battery and just telling it to not tx on no fix....
          > but would it TX that one last time? I think not.
          >
          > An old school solution would be to have a clock mechanism wind a timer and
          > the timer would switch off after a while.... like those single gang windup
          > timers at lowes.
          >
          > At one time, I did use an RV break away emergency brake switch under a
          > trailer attached to a stake in the yard, but that won't fill the bill this
          > time round.
          >
          > Any suggestions?
          >
          > Wes
          > ---
          > The world needs more geniuses with humility because there are so few of us
          > left.
          >
          >
          >
          >
          >


          --
          James
          VE6SRV
        • Scott Miller
          Maybe use scripting on the T2 to determine when it s done (ignition-switched power is off, and last position has been sent) and then use the PULSE command to
          Message 4 of 9 , Jun 10, 2011
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            Maybe use scripting on the T2 to determine when it's done
            (ignition-switched power is off, and last position has been sent) and
            then use the PULSE command to switch off a dual-coil latched relay, that
            would get switched back on by the ignition-switched circuit?

            I'll probably have another solution by the end of the summer. I'm
            setting up radios in my travel trailer and want to add a very low-power
            system for monitoring battery and solar charge state, plus inside and
            outside temperature and humidity. And of course position if it starts
            moving. I'll try to keep anything I come up with generic enough that it
            can be rolled into the standard firmware, and maybe future hardware
            revisions.

            Not looking forward to installing the sensor in the black water tank,
            though...

            Scott

            On 6/8/2011 10:49 AM, Wes Johnston, AI4PX wrote:
            > I have an ATV that I only use on the weekends sometimes not for 2 or 3
            > weeks at a time. I'd like to put a tracker on it that has absolutely 0
            > current draw when off. Yes, I know I could program the T2 to not
            > transmit if the voltage is below 13.0, but it still has to draw power to
            > check the battery. What I'd like to do is have it automatically come on
            > and after the ATV is parked tx one last time and go to a zero power state.
            > To this end, I've thought about a latched relay that gets interupted by
            > the PTT, but it would just stay on until the moment PTT was asserted and
            > turn off just as the packet started to tx. Probably the best solution
            > is to have a relay unlatch on the rising edge of PTT.
            > I've also thought about putting the GPS on switched power (ignition
            > switch) and the T2 tied to the battery and just telling it to not tx on
            > no fix.... but would it TX that one last time? I think not.
            > An old school solution would be to have a clock mechanism wind a timer
            > and the timer would switch off after a while.... like those single gang
            > windup timers at lowes.
            > At one time, I did use an RV break away emergency brake switch under a
            > trailer attached to a stake in the yard, but that won't fill the bill
            > this time round.
            > Any suggestions?
            >
            > Wes
            > ---
            > The world needs more geniuses with humility because there are so few of
            > us left.
            >
            >
          • Wes Johnston, AI4PX
            FWIW, I once made a antenna flipper out of a DC antenna rotator. I installed limit switches inside to allow it to rotate only 90 degrees and stop. I wired
            Message 5 of 9 , Jun 10, 2011
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              FWIW, I once made a antenna "flipper" out of a DC antenna rotator.  I installed limit switches inside to allow it to rotate only 90 degrees and stop.  I wired the brake lights to a timer that drove the rotator down for 30 or 45 seconds.  The idea was that a 2m antenna was too tall to survive hitting a tree, so when you hooked a truck to the trailer, the first hit of the brake lights would auto lower the antenna.

              Wes
              ---
              The world needs more geniuses with humility because there are so few of us left.



              On Fri, Jun 10, 2011 at 22:24, Scott Miller <scott@...> wrote:
              Maybe use scripting on the T2 to determine when it's done
              (ignition-switched power is off, and last position has been sent) and
              then use the PULSE command to switch off a dual-coil latched relay, that
              would get switched back on by the ignition-switched circuit?

              I'll probably have another solution by the end of the summer.  I'm
              setting up radios in my travel trailer and want to add a very low-power
              system for monitoring battery and solar charge state, plus inside and
              outside temperature and humidity.  And of course position if it starts
              moving.  I'll try to keep anything I come up with generic enough that it
              can be rolled into the standard firmware, and maybe future hardware
              revisions.

              Not looking forward to installing the sensor in the black water tank,
              though...

              Scott

              On 6/8/2011 10:49 AM, Wes Johnston, AI4PX wrote:
              > I have an ATV that I only use on the weekends sometimes not for 2 or 3
              > weeks at a time.  I'd like to put a tracker on it that has absolutely 0
              > current draw when off.  Yes, I know I could program the T2 to not
              > transmit if the voltage is below 13.0, but it still has to draw power to
              > check the battery.  What I'd like to do is have it automatically come on
              > and after the ATV is parked tx one last time and go to a zero power state.
              > To this end, I've thought about a latched relay that gets interupted by
              > the PTT, but it would just stay on until the moment PTT was asserted and
              > turn off just as the packet started to tx.  Probably the best solution
              > is to have a relay unlatch on the rising edge of PTT.
              > I've also thought about putting the GPS on switched power (ignition
              > switch) and the T2 tied to the battery and just telling it to not tx on
              > no fix.... but would it TX that one last time?  I think not.
              > An old school solution would be to have a clock mechanism wind a timer
              > and the timer would switch off after a while.... like those single gang
              > windup timers at lowes.
              > At one time, I did use an RV break away emergency brake switch under a
              > trailer attached to a stake in the yard, but that won't fill the bill
              > this time round.
              > Any suggestions?
              >
              > Wes
              > ---
              > The world needs more geniuses with humility because there are so few of
              > us left.
              >
              >



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            • Bill Black
              Hi Wes 2 parts to this... 1 Have the T2 transmit the last time beacon when the ignition goes off as in profile switch on jumper with tx on profile selected
              Message 6 of 9 , Jun 13, 2011
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                Hi Wes
                 
                2 parts to this...
                 
                1 Have the T2 transmit the last time beacon when the ignition goes off as in profile switch on jumper with tx on profile selected checked. Relay driven from the ignition line, contacts between profile select input and gnd. You need this as the profile select is at 5 volts logic level. This will beacon as soon as the ignition switches off
                 
                2 Power the radio, T2, etc through a relay getting power direct from the battery. Relay is driven from the ignition line through a diode and low ohms resistor with a large capacitor across the relay coil. resistor is to reduce in-rush current when capacitor is charging up. Capacitor should be large enough to hold the relay on for 1-2 seconds, enough to send the last beacon.
                 
                A bit of refinement would be to use a small 5 volt high coil resistance relay to drive the larger 12 volt power switching relay. Still have the ign line go through a diode but to a higher ohms resistor (1.2 - 1.4 x the relay coil resistance). Then 4.7 volt zener diode and capacitor across the relay coil. This will delay turn on while starting as well as delayed turn off also minimise arching on the power contacts as the capacitor will have the relay contacts operating slowly.
                 
                Hope this helps
                 
                 
                Bill
              • ac2ev
                What about a Super capacitor or small secondary power source that can survive a full discharge? You would want to size it so that it could power the radio
                Message 7 of 9 , Jun 15, 2011
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                  What about a "Super capacitor" or small secondary power source that can survive a full discharge? You would want to size it so that it could power the radio for a short time before it is discharged. Then when the ATV is started back up it would charge again.

                  8< snip
                  --- In tracker2@yahoogroups.com, "Wes Johnston, AI4PX" <johnstonwes@...> wrote:
                  >
                  > I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks
                  > at a time. I'd like to put a tracker on it that has absolutely 0 current
                  > draw when off. Yes, I know I could program the T2 to not transmit if the
                  > voltage is below 13.0, but it still has to draw power to check the battery.
                  > What I'd like to do is have it automatically come on and after the ATV is
                  > parked tx one last time and go to a zero power state.
                  >
                  > To this end, I've thought about a latched relay that gets interupted by the
                  > PTT, but it would just stay on until the moment PTT was asserted and turn
                  > off just as the packet started to tx. Probably the best solution is to have
                  > a relay unlatch on the rising edge of PTT.
                  >
                  > I've also thought about putting the GPS on switched power (ignition switch)
                  > and the T2 tied to the battery and just telling it to not tx on no fix....
                • Wes Johnston, AI4PX
                  I had drawn up a circuit that used two 555 timers, 1 fires 5 minutes after shutdown, the other fires one second after that to break a latched relay. It just
                  Message 8 of 9 , Jun 15, 2011
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                    I had drawn up a circuit that used two 555 timers, 1 fires 5 minutes after shutdown, the other fires one second after that to break a latched relay.  It just got to a point where the parts count and complexity was/is just too high.  It could easily be done with a small pic processor clocked at 32khz or so....  I do like the idea of a relay staying on until PTT gets asserted one last time.

                    but, since the ATV is confined to the area right around my house, I decided it would just be easier to set it at a fixed beacon rate of once a minute and a minimal path and the timer can then be a RC network on the base of a darlington pair that drives the relay.  Moderately sized eletrolytics can hold that up for 3 or 4 minutes before releasing the relay. 
                    Wes
                    ---
                    The world needs more geniuses with humility because there are so few of us left.



                    On Wed, Jun 15, 2011 at 18:16, ac2ev <ac2ev@...> wrote:
                    What about a "Super capacitor" or small secondary power source that can survive a full discharge? You would want to size it so that it could power the radio for a short time before it is discharged. Then when the ATV is started back up it would charge again.

                    8< snip
                    --- In tracker2@yahoogroups.com, "Wes Johnston, AI4PX" <johnstonwes@...> wrote:
                    >
                    > I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks
                    > at a time.  I'd like to put a tracker on it that has absolutely 0 current
                    > draw when off.  Yes, I know I could program the T2 to not transmit if the
                    > voltage is below 13.0, but it still has to draw power to check the battery.
                    > What I'd like to do is have it automatically come on and after the ATV is
                    > parked tx one last time and go to a zero power state.
                    >
                    > To this end, I've thought about a latched relay that gets interupted by the
                    > PTT, but it would just stay on until the moment PTT was asserted and turn
                    > off just as the packet started to tx.  Probably the best solution is to have
                    > a relay unlatch on the rising edge of PTT.
                    >
                    > I've also thought about putting the GPS on switched power (ignition switch)
                    > and the T2 tied to the battery and just telling it to not tx on no fix....



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                  • VE3ID
                    Occam s razor applies. Use the simplest solution. As a young engineer, my chief engineer asked me to design a system to give a secondary request-to-send pulse
                    Message 9 of 9 , Jun 15, 2011
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                      Occam's razor applies.  Use the simplest solution.

                      As a young engineer, my chief engineer asked me to design a system to give a secondary request-to-send pulse for 300 mS over a com line to trigger a cash register tape to rewind and send its data.

                      I used a crystal oscillator, and a count-down set of flip-flops, to arrive at the 300 mS, Heath Robinson (Rube Goldberg for you Americans) would have been proud of my effort.  I proudly showed it to the chief engineer and he laughed, replacing it with a simple RC network.

                      Nowadays we have supercaps, I would go with the idea of using one to keep the radio and tracker up for one last beacon.

                      73
                      Nigel
                      ve3id


                      On 15/06/11 19:08, Wes Johnston, AI4PX wrote:  

                      I had drawn up a circuit that used two 555 timers, 1 fires 5 minutes after shutdown, the other fires one second after that to break a latched relay.  It just got to a point where the parts count and complexity was/is just too high.  It could easily be done with a small pic processor clocked at 32khz or so....  I do like the idea of a relay staying on until PTT gets asserted one last time.

                      but, since the ATV is confined to the area right around my house, I decided it would just be easier to set it at a fixed beacon rate of once a minute and a minimal path and the timer can then be a RC network on the base of a darlington pair that drives the relay.  Moderately sized eletrolytics can hold that up for 3 or 4 minutes before releasing the relay. 
                      Wes

                      ---
                      The world needs more geniuses with humility because there are so few of us left.



                      On Wed, Jun 15, 2011 at 18:16, ac2ev <ac2ev@...> wrote:
                      What about a "Super capacitor" or small secondary power source that can survive a full discharge? You would want to size it so that it could power the radio for a short time before it is discharged. Then when the ATV is started back up it would charge again.

                      8< snip
                      --- In tracker2@yahoogroups.com, "Wes Johnston, AI4PX" <johnstonwes@...> wrote:
                      >
                      > I have an ATV that I only use on the weekends sometimes not for 2 or 3 weeks
                      > at a time.  I'd like to put a tracker on it that has absolutely 0 current
                      > draw when off.  Yes, I know I could program the T2 to not transmit if the
                      > voltage is below 13.0, but it still has to draw power to check the battery.
                      > What I'd like to do is have it automatically come on and after the ATV is
                      > parked tx one last time and go to a zero power state.
                      >
                      > To this end, I've thought about a latched relay that gets interupted by the
                      > PTT, but it would just stay on until the moment PTT was asserted and turn
                      > off just as the packet started to tx.  Probably the best solution is to have
                      > a relay unlatch on the rising edge of PTT.
                      >
                      > I've also thought about putting the GPS on switched power (ignition switch)
                      > and the T2 tied to the battery and just telling it to not tx on no fix....



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