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Re: [tracker2] Replacing Older OT1m System

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  • 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 1 of 13 , Jan 16, 2013
      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.



      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!


      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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