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Re: Replacing Older OT1m System

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  • MarcGorelnik
    Thanks for the responses. Actually, a tracker drawing negative current would be ideal! Sadly, the laws of physics prohibit such a tracker. I wasn t aware that
    Message 1 of 13 , Jan 14, 2013
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      Thanks for the responses.

      Actually, a tracker drawing negative current would be ideal! Sadly, the laws of physics prohibit such a tracker. I wasn't aware that the OT1m draws only 8 mA. I could live with that. I would like to keep the entire system under 25 Ah/month, which works out to an average draw of 35mA.

      Assuming the tracker draws only 8 mA and the duty cycle of the switched radio is low enough to be negligible, then the trick is to find either: (1) a low power GPS unit (~25 mA); or (2) a tracker that can switch the GPS power and standby until the signal is valid. 

      Switching the power on the GPS would defeat SmartBeaconing, but that might be a price worth paying. 

      Right now, the unit is set to transmit every 15 minutes when not in motion. Because there's a fair amount of APRS activity in the SF Bay Area, usually less than half of the transmissions are received by an iGate station. (There may also be an issue with the radio and transmission line, which is why I'll be changing those out.) That duty cycle ought to consume negligible power. Since the battery drain has recently increased markedly, I must assume that the OT1m is not properly switching power. (Or the GPS is binging on current - less likely.)

      I've thought about a solar panel, but there is no place to mount it on a covered boat. I'd have to mount it remotely and run a cable. That's certainly an option, but I'd prefer a simpler, self-contained solution.

      I know that the OT3m will switch power to the radio, but it draws 40 mA at idle per the website. That's disqualifying.  The remaining Argent candidates are:

      1. The T3-301. I couldn't find its current at idle. I would still need to either switch power to the GPS (external relay required?) or find a low-power GPS receiver.

      2. The OpenTracker USB. I can't find its current consumption at idle. I would also need build a small external board to handle radio (and perhaps GPS) power switching.

      3. Buy and build the discontinued OT1+. I would also need build a small external board to handle radio (and perhaps GPS) power switching.

      Switching power to the radio seems rather straightforward. Less clear is the ability to switch power to the GPS, wait for the fix, and then transmit. I recall from the manual, I believe, that the tracker will keep the power engaged until the next beacon if the fix is not good. That would substantially increase the duty cycle on the radio and consume more power than could ever be saved by reducing the GPS duty cycle. (Unless the tracker can separately and smartly switch GPS and radio power).

      Thanks in advance for any further comments.

      Marc
      K6MMG

      P.S. I haven't mentioned the GPS current draw because I don't know and because I have been seeking a solution (switched power) that would make the current draw relatively immaterial.


      --- In tracker2@yahoogroups.com, James Ewen wrote:
      >
      > On Sun, Jan 13, 2013 at 6:50 PM, MarcGorelnik wrote:
      >
      > > 1. Tracker with low stand-by current.
      >
      > What would be an acceptable standby current? Obviously it's going to
      > be pretty difficult to get a unit that uses a negative amount of
      > power, ie. one that charges your battery.
      >
      > With an 8 mA draw being too much, it's probably going to be tough to
      > get much lower.
      >
      > How much current does your GPS draw? You say you're probably going to
      > keep it, and you leave it running 24/7, but you have not told us the
      > current draw.
      >
      > The VX-8 draws no current when turned off, which you say is controlled
      > by the OT1, so it does not cause any drain unless it is powered up and
      > transmitting. How often do you power up and transmit when in dock, or
      > on the trailer? There's no need to beacon every minute or two... you
      > could send one position report a day while tied up or on the trailer.
      > Using profile switching based on speed, you could set the unit up so
      > it sits dormant 99.999% of the time, but once you get moving, the unit
      > will switch to the moving profile and beacon away.
      >
      > So really you only have 2 components drawing current from the battery,
      > the OT1 at 8 mA, and an unknown draw from the GPS. You get a momentary
      > higher current draw once a day when the radio sends a packet for you.
      >
      > Have you thought about a solar panel on the boat to trickle charge the
      > battery? Even a small solar panel would offset an 8 mA draw, and a
      > momentary transmission once a day. I can't comment on an unknown GPS
      > current draw though.
      >
      > --
      > James
      > VE6SRV
      >
    • Scott Miller
      Hi, ... Have you put an ammeter on it to check what it s drawing? The GPS receiver will probably draw around 50 mA, and an OT1m maybe around 12 mA. For
      Message 2 of 13 , Jan 14, 2013
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        Hi,

        > The current system consists of:
        > 1. OT1m
        > 2. VX150 2m radio (power switched by OT1m)
        > 3. GPS receiver (always powered)
        > 4. Comet B-10 antenna
        >
        > The system has always drawn too much power. (I.e., 4d battery drops
        > below 12.0 VDC after 1-2 months, which is much faster than

        Have you put an ammeter on it to check what it's drawing? The GPS
        receiver will probably draw around 50 mA, and an OT1m maybe around 12 mA.

        For current models, you can expect about 20 mA for the OTUSB and around
        70 mA for the OT3m, though that should drop with future firmware updates.

        > 1. Tracker with low stand-by current.
        > 2. Ability to power-down the radio and GPS until needed.
        > 3. 5W or more.
        > 4. Ability to plug-in laptop to send and receive Winlink email. (lowest
        > priority)

        The T3 has higher standby current, but it's also going to be your best
        bet for Winlink. I've been doing a lot of work in the last week to get
        connected mode applications working smoothly using KISS. Some of that
        will carry over to the OTUSB. A few tweaks will also go to the T2 but
        it doesn't have the extra RAM the newer units do.

        No GPS power-down yet, but as time allows I'll be experimenting with
        low-power modes on various GPS receivers.

        Scott
      • MarcGorelnik
        Scott, Thanks for the helpful response. I ll have to pull the units from the boat and do some bench testing. Something has gone amiss. Marc
        Message 3 of 13 , Jan 15, 2013
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          Scott,

          Thanks for the helpful response. I'll have to pull the units from the boat and do some bench testing. Something has gone amiss.

          Marc

          --- In tracker2@yahoogroups.com, Scott Miller wrote:
          >
          > Hi,
          >
          > > The current system consists of:
          > > 1. OT1m
          > > 2. VX150 2m radio (power switched by OT1m)
          > > 3. GPS receiver (always powered)
          > > 4. Comet B-10 antenna
          > >
          > > The system has always drawn too much power. (I.e., 4d battery drops
          > > below 12.0 VDC after 1-2 months, which is much faster than
          >
          > Have you put an ammeter on it to check what it's drawing? The GPS
          > receiver will probably draw around 50 mA, and an OT1m maybe around 12 mA.
          >
          > For current models, you can expect about 20 mA for the OTUSB and around
          > 70 mA for the OT3m, though that should drop with future firmware updates.
          >
          > > 1. Tracker with low stand-by current.
          > > 2. Ability to power-down the radio and GPS until needed.
          > > 3. 5W or more.
          > > 4. Ability to plug-in laptop to send and receive Winlink email. (lowest
          > > priority)
          >
          > The T3 has higher standby current, but it's also going to be your best
          > bet for Winlink. I've been doing a lot of work in the last week to get
          > connected mode applications working smoothly using KISS. Some of that
          > will carry over to the OTUSB. A few tweaks will also go to the T2 but
          > it doesn't have the extra RAM the newer units do.
          >
          > No GPS power-down yet, but as time allows I'll be experimenting with
          > low-power modes on various GPS receivers.
          >
          > Scott
          >
        • Matthew Cook
          I d suggest that Marcs biggest consumer of power will be the GPS 50-70mA. However switching the GPS and radio on and off together won t work since the GPS
          Message 4 of 13 , Jan 15, 2013
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            I'd suggest that Marcs biggest consumer of power will be the GPS 50-70mA.  However switching the GPS and radio on and off together won't work since the GPS requires time to lock and is variable from 3s to 30 minutes.

            Low power modes in GPS modules is a hit and miss afair, every one does it differently and not everyone is telling the truth in their datasheets either.

            I've tested litterally tested tens of different GPS chipsets for our HAB experiments and have finally settled on the Atmel ublox MAXQ series.  These at least seem to do what you tell them and when.  To get the lowest power consumption you have to drop the majority of GPS units out of NMEA mode and switch to binary.  That way you can hot start (aka poll) the GPS module when *you* want a position report, wait 1s for the next response and then transmit.  So far I've got the current consumption of the Atmel ublox module down to 12mA (hot start) with a passive chip antenna.  It hot starts in under 1s, peaks at 50mA for 3s every time I poll the unit (negligible).  However aquisition draws 72mA until lock/position is attained and then drops to hot start.

            I've also been working on a APRS tracker for my boat, which does pretty much the same thing as what Marc is doing.  I'm more interested in knowing its still where I left it, that the bilge is empty and that the batteries are in good condition (telemetry).  I now live 25mi from the marina, so it's a long round trip every fortnight to go and check.

            Scott if you were to look at low power modes then it would be worth switching to the binary protocol and looking for a GPS module with hot start capabilities.   I think it wouldn 't be too hard to then put in a script that allowed us to switch profiles when the boat starts to move, which then switches from a 30min update rate to a smart beaconing routine taylored for yachts/power boats. It's then just a simple matter of switching the HT at the appropriate time. It would also be nice if we could somehow get the PARAM information into the TNC so that APRS.fi can give us pretty graphs of battery volts etc.   I'd certainly be willing to buy/build/test such a unit.  I've got two boats to test it on (yes I'm greedy and likes my boating/fishing), and a mate of mine has a shiny new sports car that sits in his garage that wants one also.   Definitely food for thought.

            73's

            Matthew
            VK5ZM

            On 15 January 2013 06:55, Scott Miller <scott@...> wrote:
             

            Hi,



            > The current system consists of:
            > 1. OT1m
            > 2. VX150 2m radio (power switched by OT1m)
            > 3. GPS receiver (always powered)
            > 4. Comet B-10 antenna
            >
            > The system has always drawn too much power. (I.e., 4d battery drops
            > below 12.0 VDC after 1-2 months, which is much faster than

            Have you put an ammeter on it to check what it's drawing? The GPS
            receiver will probably draw around 50 mA, and an OT1m maybe around 12 mA.

            For current models, you can expect about 20 mA for the OTUSB and around
            70 mA for the OT3m, though that should drop with future firmware updates.


            > 1. Tracker with low stand-by current.
            > 2. Ability to power-down the radio and GPS until needed.
            > 3. 5W or more.
            > 4. Ability to plug-in laptop to send and receive Winlink email. (lowest
            > priority)

            The T3 has higher standby current, but it's also going to be your best
            bet for Winlink. I've been doing a lot of work in the last week to get
            connected mode applications working smoothly using KISS. Some of that
            will carry over to the OTUSB. A few tweaks will also go to the T2 but
            it doesn't have the extra RAM the newer units do.

            No GPS power-down yet, but as time allows I'll be experimenting with
            low-power modes on various GPS receivers.

            Scott




            --
            Matthew
            VK5ZM
            0487 653 245
          • Scott Miller
            ... I ll probably start with the GT320FW. I ve got specs on the Prolific binary format around here somewhere. I m mostly not sure how good the first fix or
            Message 5 of 13 , Jan 15, 2013
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              > Scott if you were to look at low power modes then it would be worth
              > switching to the binary protocol and looking for a GPS module with hot
              > start capabilities. I think it wouldn 't be too hard to then put in a

              I'll probably start with the GT320FW. I've got specs on the Prolific
              binary format around here somewhere. I'm mostly not sure how good the
              first fix or two will be.

              > could somehow get the PARAM information into the TNC so that APRS.fi can
              > give us pretty graphs of battery volts etc. I'd certainly be willing
              > to buy/build/test such a unit. I've got two boats to test it on (yes

              Do you mean from an NMEA stream? Send me samples and I'll see what can
              be done.

              Don't be surprised if I'm not very responsive this week, though. Parts
              are due in tomorrow morning and we'll be going flat out for a day or two
              trying to get caught up.

              Scott
            • James Ewen
              ... We already have the scripting capability, profile switching based on speed, and fixed rate/SmartBeaconing. Using the binary protocol however would mean
              Message 6 of 13 , Jan 15, 2013
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                On Tue, Jan 15, 2013 at 8:42 PM, Matthew Cook <vk5zm@...> wrote:

                > Scott if you were to look at low power modes then it would be worth
                > switching to the binary protocol and looking for a GPS module with hot start
                > capabilities. I think it wouldn 't be too hard to then put in a script
                > that allowed us to switch profiles when the boat starts to move, which then
                > switches from a 30min update rate to a smart beaconing routine taylored for
                > yachts/power boats.

                We already have the scripting capability, profile switching based on
                speed, and fixed rate/SmartBeaconing. Using the binary protocol
                however would mean that you would be limited one one specific GPS, or
                series of GPS as each one will have a proprietary communications
                protocol. NMEA is a common language.

                > It's then just a simple matter of switching the HT at
                > the appropriate time. It would also be nice if we could somehow get the
                > PARAM information into the TNC so that APRS.fi can give us pretty graphs of
                > battery volts etc.

                You can do that with scripting right now. Not many places display the
                telemetry parameters. If you are only wanting to get the parameters
                into aprs.fi, you can simply send the parameters once, and they will
                "stick" for a very long time.

                > I'd certainly be willing to buy/build/test such a unit.
                > I've got two boats to test it on (yes I'm greedy and likes my
                > boating/fishing), and a mate of mine has a shiny new sports car that sits in
                > his garage that wants one also. Definitely food for thought.

                Pony up the pennies... you've got 95% of what you are asking for
                sitting on the shelf!

                The OT+ will do everything you want except talk in a proprietary
                binary mode to the GPS of your choice, and poll it for a position.

                --
                James
                VE6SRV
              • Matthew Cook
                I ve already stumped the pennies into a T2 + Alinco HT for my yacht at least. The scripts were easily written, mind you took me a while to debug. To solve
                Message 7 of 13 , Jan 16, 2013
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                  I've already stumped the pennies into a T2 + Alinco HT for my yacht at least.  The scripts were easily written, mind you took me a while to debug.

                  To solve this GPS Power/APRS tracker problem I've been working on a MSP430 that sits between the T2 and the GPS.  The MSP430 puts the GPS (ublox) into binary low power mode (hot start) and implements a variable GPS polling period (based upon speed) and then simply tells lies to the T2 every second by sending fake NMEA sentances.  The MSP430 currently adds 2mA to my overall consumption.  I've down to 25-27mA depending on how to look at the AVO.

                  The MSP430 sits there and polls the GPS and watches the speed.  If the speed starts to change then the GPS polling period is varied, this should sound familiar?  Yes I've simply copied the SmartBeaconing(TM) algorithm again.

                  Anyway if we could get a T3 that can read any one of the GPS units in a low power (and if necessary binary) mode and poll the GPS for a position before transmit then I'd certainly be looking for such a unit.  Programming my MSP430 is a PITA, since I've got to copy the SmartBeaconing parameters out of the T2 and feed them into my software.  It works but it's certainly not production ready, nor do I wish to release/develop this further.  Was just trying to solve the same problem as Marc.

                  I hope that the ideas above gives Scott some thoughts as to how this low power GPS mode could be useful.

                  I've found the hot start mechanism in the Atmel ublox is pretty good, meaning the positions when polled are coming out as expected.  The prolific chipsets I had no end of trouble with in general.  They were not as well supported as the ublox in terms of others having used them.

                  With regard to the GPS, having a unit that can mount on the deck of the boat and sends serial back (hockey puck style) would be preferable to say a GPS module within the T3.  An internal module would require an external antenna with active preamp to get around the cable loss and NF issues, which adds 10-12mA to the overall current consumption; this will blow your power budget.

                  The HT and T2 I've hidden under the deck using the HT rubber duck.  I've found that this gets into the local APRS system well when the boat is on the hard and isn't too shabby when out to sea.  I'm luck that my boat is plywood/fibreglass so no issues with faraday shields etc.  External 2m marine antennas aren't easily obtainable here in Australia, I'm certainly interested in any suggestions other APRS yachties might have, especially dual band inc 70cm :)

                  73's

                  Matthew
                  VK5ZM

                  On 16 January 2013 15:10, James Ewen <ve6srv@...> wrote:
                   

                  On Tue, Jan 15, 2013 at 8:42 PM, Matthew Cook vk5zm@...> wrote:

                  > Scott if you were to look at low power modes then it would be worth
                  > switching to the binary protocol and looking for a GPS module with hot start
                  > capabilities. I think it wouldn 't be too hard to then put in a script
                  > that allowed us to switch profiles when the boat starts to move, which then
                  > switches from a 30min update rate to a smart beaconing routine taylored for
                  > yachts/power boats.

                  We already have the scripting capability, profile switching based on
                  speed, and fixed rate/SmartBeaconing. Using the binary protocol
                  however would mean that you would be limited one one specific GPS, or
                  series of GPS as each one will have a proprietary communications
                  protocol. NMEA is a common language.


                  > It's then just a simple matter of switching the HT at
                  > the appropriate time. It would also be nice if we could somehow get the
                  > PARAM information into the TNC so that APRS.fi can give us pretty graphs of
                  > battery volts etc.

                  You can do that with scripting right now. Not many places display the
                  telemetry parameters. If you are only wanting to get the parameters
                  into aprs.fi, you can simply send the parameters once, and they will
                  "stick" for a very long time.


                  > I'd certainly be willing to buy/build/test such a unit.
                  > I've got two boats to test it on (yes I'm greedy and likes my
                  > boating/fishing), and a mate of mine has a shiny new sports car that sits in
                  > his garage that wants one also. Definitely food for thought.

                  Pony up the pennies... you've got 95% of what you are asking for
                  sitting on the shelf!

                  The OT+ will do everything you want except talk in a proprietary
                  binary mode to the GPS of your choice, and poll it for a position.

                  --
                  James
                  VE6SRV




                  --
                  Matthew
                  VK5ZM
                  0487 653 245
                • Matthew Cook
                  I ve already stumped the pennies into a T2 + Alinco HT for my yacht at least. The scripts were easily written, mind you took me a while to debug. To solve
                  Message 8 of 13 , Jan 16, 2013
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                    I've already stumped the pennies into a T2 + Alinco HT for my yacht at least.  The scripts were easily written, mind you took me a while to debug.

                    To solve this GPS Power/APRS tracker problem I've been working on a MSP430 that sits between the T2 and the GPS.  The MSP430 puts the GPS (ublox) into binary low power mode (hot start) and implements a variable GPS polling period (based upon speed) and then simply tells lies to the T2 every second by sending fake NMEA sentances.  The MSP430 currently adds 2mA to my overall consumption.  I've down to 25-27mA depending on how to look at the AVO.

                    The MSP430 sits there and polls the GPS and watches the speed.  If the speed starts to change then the GPS polling period is varied, this should sound familiar?  Yes I've simply copied the SmartBeaconing(TM) algorithm again.

                    Anyway if we could get a T3 that can read any one of the GPS units in a low power (and if necessary binary) mode and poll the GPS for a position before transmit then I'd certainly be looking for such a unit.  Programming my MSP430 is a PITA, since I've got to copy the SmartBeaconing parameters out of the T2 and feed them into my software.  It works but it's certainly not production ready, nor do I wish to release/develop this further.  Was just trying to solve the same problem as Marc.

                    I hope that the ideas above gives Scott some thoughts as to how this low power GPS mode could be useful.

                    I've found the hot start mechanism in the Atmel ublox is pretty good, meaning the positions when polled are coming out as expected.  The prolific chipsets I had no end of trouble with in general.  They were not as well supported as the ublox in terms of others having used them.

                    With regard to the GPS, having a unit that can mount on the deck of the boat and sends serial back (hockey puck style) would be preferable to say a GPS module within the T3.  An internal module would require an external antenna with active preamp to get around the cable loss and NF issues, which adds 10-12mA to the overall current consumption; this will blow your power budget.

                    The HT and T2 I've hidden under the deck using the HT rubber duck.  I've found that this gets into the local APRS system well when the boat is on the hard and isn't too shabby when out to sea.  I'm luck that my boat is plywood/fibreglass so no issues with faraday shields etc.  External 2m marine antennas aren't easily obtainable here in Australia, I'm certainly interested in any suggestions other APRS yachties might have, especially dual band inc 70cm :)

                    73's

                    Matthew
                    VK5ZM

                    On 16 January 2013 15:10, James Ewen <ve6srv@...> wrote:
                     

                    On Tue, Jan 15, 2013 at 8:42 PM, Matthew Cook vk5zm@...> wrote:

                    > Scott if you were to look at low power modes then it would be worth
                    > switching to the binary protocol and looking for a GPS module with hot start
                    > capabilities. I think it wouldn 't be too hard to then put in a script
                    > that allowed us to switch profiles when the boat starts to move, which then
                    > switches from a 30min update rate to a smart beaconing routine taylored for
                    > yachts/power boats.

                    We already have the scripting capability, profile switching based on
                    speed, and fixed rate/SmartBeaconing. Using the binary protocol
                    however would mean that you would be limited one one specific GPS, or
                    series of GPS as each one will have a proprietary communications
                    protocol. NMEA is a common language.


                    > It's then just a simple matter of switching the HT at
                    > the appropriate time. It would also be nice if we could somehow get the
                    > PARAM information into the TNC so that APRS.fi can give us pretty graphs of
                    > battery volts etc.

                    You can do that with scripting right now. Not many places display the
                    telemetry parameters. If you are only wanting to get the parameters
                    into aprs.fi, you can simply send the parameters once, and they will
                    "stick" for a very long time.


                    > I'd certainly be willing to buy/build/test such a unit.
                    > I've got two boats to test it on (yes I'm greedy and likes my
                    > boating/fishing), and a mate of mine has a shiny new sports car that sits in
                    > his garage that wants one also. Definitely food for thought.

                    Pony up the pennies... you've got 95% of what you are asking for
                    sitting on the shelf!

                    The OT+ will do everything you want except talk in a proprietary
                    binary mode to the GPS of your choice, and poll it for a position.

                    --
                    James
                    VE6SRV




                    --
                    Matthew
                    VK5ZM
                    0487 653 245
                  • Scott Miller
                    Hi Matthew, I think you ve shared some of the documentation with me before, but it s been a while and I don t remember the details. I d be happy to look over
                    Message 9 of 13 , Jan 16, 2013
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                      Hi Matthew,

                      I think you've shared some of the documentation with me before, but it's
                      been a while and I don't remember the details. I'd be happy to look
                      over it again and see if I can incorporate some of that into the T3 and
                      maybe the T2. Turns out one compiler optimization wasn't enabled and I
                      have something like 800 bytes to work with on the T2 now!

                      Scott

                      On 1/16/2013 8:23 PM, Matthew Cook wrote:
                      > I've already stumped the pennies into a T2 + Alinco HT for my yacht at
                      > least. The scripts were easily written, mind you took me a while to debug.
                      >
                      > To solve this GPS Power/APRS tracker problem I've been working on a
                      > MSP430 that sits between the T2 and the GPS. The MSP430 puts the GPS
                      > (ublox) into binary low power mode (hot start) and implements a variable
                      > GPS polling period (based upon speed) and then simply tells lies to the
                      > T2 every second by sending fake NMEA sentances. The MSP430 currently
                      > adds 2mA to my overall consumption. I've down to 25-27mA depending on
                      > how to look at the AVO.
                      >
                      > The MSP430 sits there and polls the GPS and watches the speed. If the
                      > speed starts to change then the GPS polling period is varied, this
                      > should sound familiar? Yes I've simply copied the SmartBeaconing(TM)
                      > algorithm again.
                      >
                      > Anyway if we could get a T3 that can read any one of the GPS units in a
                      > low power (and if necessary binary) mode and poll the GPS for a position
                      > before transmit then I'd certainly be looking for such a unit.
                      > Programming my MSP430 is a PITA, since I've got to copy the
                      > SmartBeaconing parameters out of the T2 and feed them into my software.
                      > It works but it's certainly not production ready, nor do I wish to
                      > release/develop this further. Was just trying to solve the same problem
                      > as Marc.
                      >
                      > I hope that the ideas above gives Scott some thoughts as to how this low
                      > power GPS mode could be useful.
                      >
                      > I've found the hot start mechanism in the Atmel ublox is pretty good,
                      > meaning the positions when polled are coming out as expected. The
                      > prolific chipsets I had no end of trouble with in general. They were
                      > not as well supported as the ublox in terms of others having used them.
                      >
                      > With regard to the GPS, having a unit that can mount on the deck of the
                      > boat and sends serial back (hockey puck style) would be preferable to
                      > say a GPS module within the T3. An internal module would require an
                      > external antenna with active preamp to get around the cable loss and NF
                      > issues, which adds 10-12mA to the overall current consumption; this will
                      > blow your power budget.
                      >
                      > The HT and T2 I've hidden under the deck using the HT rubber duck. I've
                      > found that this gets into the local APRS system well when the boat is on
                      > the hard and isn't too shabby when out to sea. I'm luck that my boat is
                      > plywood/fibreglass so no issues with faraday shields etc. External 2m
                      > marine antennas aren't easily obtainable here in Australia, I'm
                      > certainly interested in any suggestions other APRS yachties might have,
                      > especially dual band inc 70cm :)
                      >
                      > 73's
                      >
                      > Matthew
                      > VK5ZM
                      >
                      > On 16 January 2013 15:10, James Ewen <ve6srv@...
                      > <mailto:ve6srv@...>> wrote:
                      >
                      > __
                      >
                      > On Tue, Jan 15, 2013 at 8:42 PM, Matthew Cook vk5zm@...
                      > <mailto:vk5zm%40bistre.net>> wrote:
                      >
                      > > Scott if you were to look at low power modes then it would be worth
                      > > switching to the binary protocol and looking for a GPS module
                      > with hot start
                      > > capabilities. I think it wouldn 't be too hard to then put in a
                      > script
                      > > that allowed us to switch profiles when the boat starts to move,
                      > which then
                      > > switches from a 30min update rate to a smart beaconing routine
                      > taylored for
                      > > yachts/power boats.
                      >
                      > We already have the scripting capability, profile switching based on
                      > speed, and fixed rate/SmartBeaconing. Using the binary protocol
                      > however would mean that you would be limited one one specific GPS, or
                      > series of GPS as each one will have a proprietary communications
                      > protocol. NMEA is a common language.
                      >
                      >
                      > > It's then just a simple matter of switching the HT at
                      > > the appropriate time. It would also be nice if we could somehow
                      > get the
                      > > PARAM information into the TNC so that APRS.fi can give us pretty
                      > graphs of
                      > > battery volts etc.
                      >
                      > You can do that with scripting right now. Not many places display the
                      > telemetry parameters. If you are only wanting to get the parameters
                      > into aprs.fi <http://aprs.fi>, you can simply send the parameters
                      > once, and they will
                      > "stick" for a very long time.
                      >
                      >
                      > > I'd certainly be willing to buy/build/test such a unit.
                      > > I've got two boats to test it on (yes I'm greedy and likes my
                      > > boating/fishing), and a mate of mine has a shiny new sports car
                      > that sits in
                      > > his garage that wants one also. Definitely food for thought.
                      >
                      > Pony up the pennies... you've got 95% of what you are asking for
                      > sitting on the shelf!
                      >
                      > The OT+ will do everything you want except talk in a proprietary
                      > binary mode to the GPS of your choice, and poll it for a position.
                      >
                      > --
                      > James
                      > VE6SRV
                      >
                      >
                      >
                      >
                      > --
                      > Matthew
                      > VK5ZM
                      > 0487 653 245
                      >
                      >
                    • Matthew Cook
                      Hi Scott, I ll go over my notes on the weekend when I get home and send you through some info. I m about 300mi from home at the moment out in the country side
                      Message 10 of 13 , Jan 16, 2013
                      • 0 Attachment
                        Hi Scott,

                        I'll go over my notes on the weekend when I get home and send you through some info.

                        I'm about 300mi from home at the moment out in the country side with my trusty laptop, 3G wireless internet modem & embedded development system literally writing and debugging code in a farmers paddock... it's just tipped over +42degC in the shade today :)

                        Anyway more soon.

                        Regards

                        Matthew

                        On 17 January 2013 15:54, Scott Miller <scott@...> wrote:
                        Hi Matthew,

                        I think you've shared some of the documentation with me before, but it's
                        been a while and I don't remember the details.  I'd be happy to look
                        over it again and see if I can incorporate some of that into the T3 and
                        maybe the T2.  Turns out one compiler optimization wasn't enabled and I
                        have something like 800 bytes to work with on the T2 now!

                        Scott

                        On 1/16/2013 8:23 PM, Matthew Cook wrote:
                        > I've already stumped the pennies into a T2 + Alinco HT for my yacht at
                        > least.  The scripts were easily written, mind you took me a while to debug.
                        >
                        > To solve this GPS Power/APRS tracker problem I've been working on a
                        > MSP430 that sits between the T2 and the GPS.  The MSP430 puts the GPS
                        > (ublox) into binary low power mode (hot start) and implements a variable
                        > GPS polling period (based upon speed) and then simply tells lies to the
                        > T2 every second by sending fake NMEA sentances.  The MSP430 currently
                        > adds 2mA to my overall consumption.  I've down to 25-27mA depending on
                        > how to look at the AVO.
                        >
                        > The MSP430 sits there and polls the GPS and watches the speed.  If the
                        > speed starts to change then the GPS polling period is varied, this
                        > should sound familiar?  Yes I've simply copied the SmartBeaconing(TM)
                        > algorithm again.
                        >
                        > Anyway if we could get a T3 that can read any one of the GPS units in a
                        > low power (and if necessary binary) mode and poll the GPS for a position
                        > before transmit then I'd certainly be looking for such a unit.
                        > Programming my MSP430 is a PITA, since I've got to copy the
                        > SmartBeaconing parameters out of the T2 and feed them into my software.
                        > It works but it's certainly not production ready, nor do I wish to
                        > release/develop this further.  Was just trying to solve the same problem
                        > as Marc.
                        >
                        > I hope that the ideas above gives Scott some thoughts as to how this low
                        > power GPS mode could be useful.
                        >
                        > I've found the hot start mechanism in the Atmel ublox is pretty good,
                        > meaning the positions when polled are coming out as expected.  The
                        > prolific chipsets I had no end of trouble with in general.  They were
                        > not as well supported as the ublox in terms of others having used them.
                        >
                        > With regard to the GPS, having a unit that can mount on the deck of the
                        > boat and sends serial back (hockey puck style) would be preferable to
                        > say a GPS module within the T3.  An internal module would require an
                        > external antenna with active preamp to get around the cable loss and NF
                        > issues, which adds 10-12mA to the overall current consumption; this will
                        > blow your power budget.
                        >
                        > The HT and T2 I've hidden under the deck using the HT rubber duck.  I've
                        > found that this gets into the local APRS system well when the boat is on
                        > the hard and isn't too shabby when out to sea.  I'm luck that my boat is
                        > plywood/fibreglass so no issues with faraday shields etc.  External 2m
                        > marine antennas aren't easily obtainable here in Australia, I'm
                        > certainly interested in any suggestions other APRS yachties might have,
                        > especially dual band inc 70cm :)
                        >
                        > 73's
                        >
                        > Matthew
                        > VK5ZM
                        >
                        > On 16 January 2013 15:10, James Ewen <ve6srv@...
                        > <mailto:ve6srv@...>> wrote:
                        >
                        >     __
                        >
                        >     On Tue, Jan 15, 2013 at 8:42 PM, Matthew Cook vk5zm@...
                        >     <mailto:vk5zm%40bistre.net>> wrote:
                        >
                        >      > Scott if you were to look at low power modes then it would be worth
                        >      > switching to the binary protocol and looking for a GPS module
                        >     with hot start
                        >      > capabilities. I think it wouldn 't be too hard to then put in a
                        >     script
                        >      > that allowed us to switch profiles when the boat starts to move,
                        >     which then
                        >      > switches from a 30min update rate to a smart beaconing routine
                        >     taylored for
                        >      > yachts/power boats.
                        >
                        >     We already have the scripting capability, profile switching based on
                        >     speed, and fixed rate/SmartBeaconing. Using the binary protocol
                        >     however would mean that you would be limited one one specific GPS, or
                        >     series of GPS as each one will have a proprietary communications
                        >     protocol. NMEA is a common language.
                        >
                        >
                        >      > It's then just a simple matter of switching the HT at
                        >      > the appropriate time. It would also be nice if we could somehow
                        >     get the
                        >      > PARAM information into the TNC so that APRS.fi can give us pretty
                        >     graphs of
                        >      > battery volts etc.
                        >
                        >     You can do that with scripting right now. Not many places display the
                        >     telemetry parameters. If you are only wanting to get the parameters
                        >     into aprs.fi <http://aprs.fi>, you can simply send the parameters
                        >     once, and they will
                        >     "stick" for a very long time.
                        >
                        >
                        >      > I'd certainly be willing to buy/build/test such a unit.
                        >      > I've got two boats to test it on (yes I'm greedy and likes my
                        >      > boating/fishing), and a mate of mine has a shiny new sports car
                        >     that sits in
                        >      > his garage that wants one also. Definitely food for thought.
                        >
                        >     Pony up the pennies... you've got 95% of what you are asking for
                        >     sitting on the shelf!
                        >
                        >     The OT+ will do everything you want except talk in a proprietary
                        >     binary mode to the GPS of your choice, and poll it for a position.
                        >
                        >     --
                        >     James
                        >     VE6SRV
                        >
                        >
                        >
                        >
                        > --
                        > Matthew
                        > VK5ZM
                        > 0487 653 245
                        >
                        >


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                        --
                        Matthew
                        VK5ZM
                        0487 653 245
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