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RE: [tracker2] Standby mode

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  • Tony VE6MVP
    ... I am going to add some kind of disabler device which requires me to hit a switch of some sort which will then enable the fuel pump. Thus a thief who had
    Message 1 of 9 , Jul 7, 2006
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      At 11:48 AM 2006/07/07 -0700, you wrote:

      >Personally, I'd prefer to use
      >that to kill the fuel pump!

      I am going to add some kind of disabler device which requires me to hit a
      switch of some sort which will then enable the fuel pump. Thus a thief
      who had hotwired the vehicle would not be able to start it.

      Besides if the vehicle is indeed moving I'd sooner have the cops stop it
      themselves and arrest the bad guys. Rather than disabling it so they'd
      abandon the vehicle. Of course if they start running then it would be
      nice to remotely disable the fuel pump. I'm sure the cops would
      appreciate that from a bystanders viewpoint. As would I as there is likely
      to be less damage to my vehicle.

      <Rest of your response snipped>

      Wow, very nice to see just how much flexibility you're putting into the
      device.

      > > (What is the delay between beaconing and being seen on the
      > > Internet at
      > > places such as findu.com?)
      >
      >Usually not more than a second or two.

      Ah, now that's nice too. You can tell the operator a few seconds after
      making the turn, "Hit the refresh button now."

      Thanks, Tony
    • juha.nurmela@quicknet.inet.fi
      ... The password would be easy enough to change at the police station parking lot ? :) No shortage of suggestions ;) but here comes another idea. In addition
      Message 2 of 9 , Jul 7, 2006
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        On Fri, 7 Jul 2006 scott@... wrote:

        > tony> Needless to say once I used it I'd want to change the password
        >
        > I'm working on a couple of different authentication methods. It's a
        > tradeoff between ease of use and security.

        The password would be easy enough to change at the police station
        parking lot ? :)

        No shortage of suggestions ;) but here comes another idea.

        In addition to the existing remote operation;

        A code word, recognized from, say, incoming messages, which
        would just indirect into a pre-configured command. no acks no nothing.

        The command(s) intended to be idempotent, would not cause harm if Eve the
        eavesdropper replayed it (the fuelpump fuse would remain blown ;) Nor
        would Eve know what it did, if it was not obvious from subsequent tracker2
        behavior.

        codeword 'power' could be published to a larger group, to switch a power
        brick on/off for example, and the password stuff kept secret.


        Juha, OH5NXO
      • scott@opentrac.org
        ... I figured it d be better to do it once the cops had the car in sight. My Accord has a 15 amp fuse on the fuel pump, so I think the simplest way to set it
        Message 3 of 9 , Jul 7, 2006
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          > Besides if the vehicle is indeed moving I'd sooner have the
          > cops stop it
          > themselves and arrest the bad guys. Rather than disabling it
          > so they'd
          > abandon the vehicle. Of course if they start running then

          I figured it'd be better to do it once the cops had the car in sight. My
          Accord has a 15 amp fuse on the fuel pump, so I think the simplest way to
          set it up would be to power the tracker through that circuit (the high-side
          switch can't switch a separate supply), making sure it's got adequately
          heavy cabling, and just short the output leads of the switch. When the
          switch is turned on, it'll switch up to 20 amps before the current limiting
          cuts in, but that's enough to blow the fuse. You have to get out of the car
          and open an access panel to replace it.

          A simple relay might be better, though. You could also kill the ECU, but
          I'd be afraid of causing damage to the engine. Killing the fuel supply
          shouldn't do anything more dramatic than starving the engine and making the
          car coast to a stop.

          Before anyone tries to implement this, I should point out that my auto shop
          grades were... well, not quite on par with my CS/EE grades, anyway. =]

          > Wow, very nice to see just how much flexibility you're
          > putting into the
          > device.

          It'll be able to do a lot more if I ever get a chance to implement the
          scripting language I've been thinking about. That'll have to wait until
          after the first production firmware release, though.

          Scott
        • scott@opentrac.org
          ... That could be done in the hypothetical scripting language. I think it d be fine with the authentication techniques I m working on. Right now it s all
          Message 4 of 9 , Jul 7, 2006
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            > In addition to the existing remote operation;
            >
            > A code word, recognized from, say, incoming messages, which
            > would just indirect into a pre-configured command. no acks no nothing.

            That could be done in the hypothetical scripting language. I think it'd be
            fine with the authentication techniques I'm working on. Right now it's all
            callsign-based. Another one will be something you can calculate in your
            head or keep on paper, and the third will be a true cryptographic MAC
            that'll have to be generated by a computer.

            > The command(s) intended to be idempotent, would not cause
            > harm if Eve the
            > eavesdropper replayed it (the fuelpump fuse would remain blown ;) Nor
            > would Eve know what it did, if it was not obvious from
            > subsequent tracker2
            > behavior.

            Idempotence is actually a major concern in the command interface and
            scripting language design. It's very easy to get the same command multiple
            times due to retries and network topology, and the flash memory has finite
            write endurance. That's an issue in scripting if you say 'execute this
            configuration command when contact A is closed' - it'd be easy to erase and
            rewrite the same page in flash very quickly and eventually destroy it.

            My initial idea for a scripting language resembled a PLC's ladder logic,
            rather than a procedural language. I'm still leaning toward that sort of
            setup, but it introduces some complexity in dealing with output events that
            have to be edge-triggered.

            Scott
          • juha.nurmela@quicknet.inet.fi
            ... This code word would not require authentication, it would be a less-privileged thing. Instead of keys to the machine room, you d have a cord to pull, to
            Message 5 of 9 , Jul 7, 2006
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              On Fri, 7 Jul 2006 scott@... wrote:

              > That could be done in the hypothetical scripting language. I think it'd be
              > fine with the authentication techniques I'm working on.

              This 'code word' would not require authentication, it would be
              a less-privileged thing. Instead of keys to the machine room,
              you'd have a cord to pull, to reset the airconditioning.

              > Idempotence is actually a major concern in the command interface and
              > scripting language design. It's very easy to get the same command multiple

              You know the cure ;) Message identifiers.

              > My initial idea for a scripting language resembled a PLC's ladder logic,

              I guess a Forth-like language is out of the question. Easy to implement,
              but, kind of crazy to usher people to code in RPN something, what
              they could write by themselves and recompile, in the first place.




              Juha
            • scott@opentrac.org
              ... Responding to commands and initiating pre-programmed actions is a big part of what I want the scripting language to be able to do. ... Yeah, not a lot of
              Message 6 of 9 , Jul 7, 2006
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                > This 'code word' would not require authentication, it would be
                > a less-privileged thing. Instead of keys to the machine room,
                > you'd have a cord to pull, to reset the airconditioning.

                Responding to commands and initiating pre-programmed actions is a big part
                of what I want the scripting language to be able to do.

                > I guess a Forth-like language is out of the question. Easy to
                > implement,
                > but, kind of crazy to usher people to code in RPN something, what
                > they could write by themselves and recompile, in the first place.

                Yeah, not a lot of room.. but you're not the first to suggest Forth. I've
                got a book on designing 'little languages' and their interpreters... I'm
                hoping to get some insipration from that. It needs to be line-editable
                though, so you can make code changes remotely.

                Scott
              • Curt, WE7U
                ... I once wrote a Forth interpreter for a 6803 processor in under 2k. -- Curt, WE7U. APRS Client Comparisons: http://www.eskimo.com/~archer Lotto: A tax
                Message 7 of 9 , Jul 10, 2006
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                  On Fri, 7 Jul 2006 scott@... wrote:

                  > > I guess a Forth-like language is out of the question. Easy to
                  > > implement,
                  > > but, kind of crazy to usher people to code in RPN something, what
                  > > they could write by themselves and recompile, in the first place.
                  >
                  > Yeah, not a lot of room.. but you're not the first to suggest Forth. I've
                  > got a book on designing 'little languages' and their interpreters... I'm
                  > hoping to get some insipration from that. It needs to be line-editable
                  > though, so you can make code changes remotely.

                  I once wrote a Forth interpreter for a 6803 processor in under 2k.

                  --
                  Curt, WE7U. APRS Client Comparisons: http://www.eskimo.com/~archer
                  "Lotto: A tax on people who are bad at math." -- unknown
                  "Windows: Microsoft's tax on computer illiterates." -- WE7U
                  "The world DOES revolve around me: I picked the coordinate system!"
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