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Re: [nslu2-linux] Lifecycle when booting (only using) USB thumb drive.

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  • Emil Granström
    Thanks for all replies. I guess I can stop worrying about this. Brg Emil ... Thanks for all replies. I guess I can stop worrying about this. Brg Emil Brian
    Message 1 of 16 , Mar 29, 2010
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      Thanks for all replies.
      I guess I can stop worrying about this.

      Brg
       Emil

      Brian Wood wrote:
       

      On Monday 29 March 2010 12:38:26 pm Emil Granström wrote:
      > Hello. I am a newbie here using the slug.
      > I will be using the slug for temp meassurements using OWFS in our
      > cottage, I will generate graphs and alarms for critical temps.
      > I will be runing the slug from a 4GB USB thumbdrive. To reduce the
      > access of the disk I have done the "touch /.ext3flash" command.
      >
      > I assume this question is a bit hard to comment on but can anyone give
      > me a hint on what to expect when it comes to the lifecycle of the USB
      > drive ?
      > If the slug is on 24-7 how long can it be before I can expect problems ?
      > Are we talking week, months, years or what ?
      > I hope someone with a bit more handson experience can comment or share
      > some insights.

      I have a slug that's been running Debian from a flash drive for almost 3 years,
      no problems yet.

      I did set noatime, and I use almost no swap.

      It's not doing any heavy lifting, but it's been running 24/7.

      Not that this guarantees anything, just a datapoint.

    • Mike Westerhof (mwester)
      ... I have a slug installed at an old house I have been working to refurbish. It uses a network of one-wire sensors to monitor temperature inside, but more
      Message 2 of 16 , Mar 31, 2010
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        Emil Granström wrote:
        > Hello. I am a newbie here using the slug.
        > I will be using the slug for temp meassurements using OWFS in our
        > cottage, I will generate graphs and alarms for critical temps.
        > I will be runing the slug from a 4GB USB thumbdrive. To reduce the
        > access of the disk I have done the "touch /.ext3flash" command.
        >
        > I assume this question is a bit hard to comment on but can anyone give
        > me a hint on what to expect when it comes to the lifecycle of the USB
        > drive ?
        > If the slug is on 24-7 how long can it be before I can expect problems ?
        > Are we talking week, months, years or what ?
        > I hope someone with a bit more handson experience can comment or share
        > some insights.
        >

        I have a slug installed at an old house I have been working to
        refurbish. It uses a network of one-wire sensors to monitor temperature
        inside, but more importantly it measures the temperature of a few water
        pipes that are prone to freezing, and monitors the very old boiler to
        alert me should it fail.

        I use a 2 GByte flash drive -- the NSLU2 has been running without a
        reboot or restart since early last fall.

        By-the-way, I use SlugOS -- if you find Unslung to be too old and too
        "non-linux" in nature, you might try installing SlugOS 5.3-beta and then
        installing owfs from the "unstable" feeds.

        -Mike (mwester)
      • Emil Granström
        Thanks Mike, Your use seems very much like mine. I am currently testing the Unslug build but I will certainly keep the SlugOS in mind. I will connect mine to a
        Message 3 of 16 , Mar 31, 2010
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          Thanks Mike,
          Your use seems very much like mine. I am currently testing the Unslug build but I will certainly keep the SlugOS in mind.
          I will connect mine to a Dovado UMR with a Tellstick so I can use the Slug to turn on heating if I need to.
          RRDtool is doing some graphs and the Dovado UMR is suppling the internet connection via a mobile broadband connection.
          /Emil


          Mike Westerhof (mwester) wrote:
           

          Emil Granström wrote:
          > Hello. I am a newbie here using the slug.
          > I will be using the slug for temp meassurements using OWFS in our
          > cottage, I will generate graphs and alarms for critical temps.
          > I will be runing the slug from a 4GB USB thumbdrive. To reduce the
          > access of the disk I have done the "touch /.ext3flash" command.
          >
          > I assume this question is a bit hard to comment on but can anyone give
          > me a hint on what to expect when it comes to the lifecycle of the USB
          > drive ?
          > If the slug is on 24-7 how long can it be before I can expect problems ?
          > Are we talking week, months, years or what ?
          > I hope someone with a bit more handson experience can comment or share
          > some insights.
          >

          I have a slug installed at an old house I have been working to
          refurbish. It uses a network of one-wire sensors to monitor temperature
          inside, but more importantly it measures the temperature of a few water
          pipes that are prone to freezing, and monitors the very old boiler to
          alert me should it fail.

          I use a 2 GByte flash drive -- the NSLU2 has been running without a
          reboot or restart since early last fall.

          By-the-way, I use SlugOS -- if you find Unslung to be too old and too
          "non-linux" in nature, you might try installing SlugOS 5.3-beta and then
          installing owfs from the "unstable" feeds.

          -Mike (mwester)

        • lance_benson
          I ran an unslung slug for 2 and a half years off of a 512mb thumbdrive without problems--and without doing anything about swap (ymmv)--until I repurposed the
          Message 4 of 16 , Mar 31, 2010
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            I ran an unslung slug for 2 and a half years off of a 512mb thumbdrive without problems--and without doing anything about swap (ymmv)--until I repurposed the slug (the drive is still working holding files for an mp3 player).

            That said, openWrt can install completely in flash and do what you have said you want to do. I have 2 slugs in different locations doing that--monitoring temperatures and reading other sensors--no usb drive is needed. I don't use one-wire, tho--I communicate with a PICAXE microprocessor which reads the sensors and sends messages via serial to the slug--through a usb serial dongle.
          • clerew5
            ... Eh? What sort of sensor uses one wire? BTW, I have just wired up some premises with two-core cable, only to discover when I came to order the sensors that
            Message 5 of 16 , Apr 1, 2010
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              --- In nslu2-linux@yahoogroups.com, "Mike Westerhof (mwester)" <mwester@...> wrote:

              > I have a slug installed at an old house I have been working to
              > refurbish. It uses a network of one-wire sensors to monitor temperature
              > inside, but more importantly it measures the temperature of a few water
              > pipes that are prone to freezing, and monitors the very old boiler to
              > alert me should it fail.

              Eh? What sort of sensor uses one wire?

              BTW, I have just wired up some premises with two-core cable, only to discover when I came to order the sensors that they needed 3-core :-( .
            • Philip Tait
              1-wire sensors: http://en.wikipedia.org/wiki/1-Wire
              Message 6 of 16 , Apr 1, 2010
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                1-wire sensors: http://en.wikipedia.org/wiki/1-Wire

                On Thu, 2010-04-01 at 13:47 +0000, clerew5 wrote:
                >
                >
                >
                > --- In nslu2-linux@yahoogroups.com, "Mike Westerhof (mwester)"
                > <mwester@...> wrote:
                >
                > > I have a slug installed at an old house I have been working to
                > > refurbish. It uses a network of one-wire sensors to monitor
                > temperature
                > > inside, but more importantly it measures the temperature of a few
                > water
                > > pipes that are prone to freezing, and monitors the very old boiler
                > to
                > > alert me should it fail.
                >
                > Eh? What sort of sensor uses one wire?
                >
                > BTW, I have just wired up some premises with two-core cable, only to
                > discover when I came to order the sensors that they needed
                > 3-core :-( .
                >
                >
                >
                >
                >
              • clerew5
                ... Ah, but that actually requires 2-wires :-( . And it would seem that the idea is to put the A-D converter at the far end of some wire alongside the sensor.
                Message 7 of 16 , Apr 2, 2010
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                  --- In nslu2-linux@yahoogroups.com, Philip Tait <pjtait@...> wrote:
                  >
                  > 1-wire sensors: http://en.wikipedia.org/wiki/1-Wire

                  Ah, but that actually requires 2-wires :-( .

                  And it would seem that the idea is to put the A-D converter at the far end of some wire alongside the sensor.

                  And how does one interface that to a Slug? Can it be done from an i2c bus, or is it necessary to bring out the UART connection from the Slug? And can somebody recommend a suitable sensor/converter for use with that system (I am looking for a temperature resolution of 0.1°C, and an absolute accuracy not too much worse than that).

                  I would also like some advice on the path I have been following so far:

                  I intended to attach an i2c bus (that seems a well-established hack to the Slug). On that bus there will be assorted LEDs and pushbuttons, an LCD, an EEPROM, and a 4-channel 12-bit A-D converter. I had intended to use LM35DZ temperatures sensors (as manufactured by both MS and Texas). And I had identified an i2c A-D chip from the Farnell website (AD7991) that appeared to have all the required characteristics.

                  But I did not check enough. It turned out to be a SOT23 style chip which was about the size of a baby's fingernail :-( . Not nice for building on a breadboard. I looked for a suitable breakout board, but the only available one for an 8-pin SOT23 was in California, and I am in the UK. The only breakout boards readily available in the UK are for 6-pin SOTs (well, there is a possible one from Microchip, but at a ridiculous price).

                  So back to the Farnell website for a chip with a larger footprint. But they all seem of be surface mount and with TSSOP or MSOP format, where the pin spacing is still 0.025in (the same as SOT23).

                  So can anyone suggest any better chip? I might get away with SOIC format (0.05in spacing). The only chips I can find with good ol' DIL fomat are from Microchip, and they use Yet Another Nonstandard Interface (Microport).
                  >
                  > On Thu, 2010-04-01 at 13:47 +0000, clerew5 wrote:

                  > > --- In nslu2-linux@yahoogroups.com, "Mike Westerhof (mwester)"
                  > > <mwester@> wrote:
                  > >
                  > > > I have a slug installed at an old house I have been working to
                  > > > refurbish. It uses a network of one-wire sensors to monitor
                  > > temperature...
                  > >
                  > > Eh? What sort of sensor uses one wire?
                • Mike Westerhof
                  ... Indeed. Apparently somebody thought that it might be possible to use the ground in a building, for example, as the return conductor. I think that s
                  Message 8 of 16 , Apr 2, 2010
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                    clerew5 wrote:
                    > --- In nslu2-linux@yahoogroups.com, Philip Tait <pjtait@...> wrote:
                    >
                    >> 1-wire sensors: http://en.wikipedia.org/wiki/1-Wire
                    >>
                    >
                    > Ah, but that actually requires 2-wires :-( .
                    >

                    Indeed. Apparently somebody thought that it might be possible to use
                    the ground in a building, for example, as the return conductor. I think
                    that's marketing talk, as the devices really work better with a proper
                    2-wire system.

                    > And it would seem that the idea is to put the A-D converter at the far end of some wire alongside the sensor.
                    >

                    Yes. The wire (or pair of conductors, if you prefer) is actually a
                    digital network connection. Many of the devices do A-D conversion, and
                    send the results digitally back to the host. However, some devices are
                    completely digital. And some do the reverse -- I have a relay board
                    that I intend to use to control the heating/cooling system once I finish
                    this project, although right now it just blinks LEDs and looks cool -
                    everyone likes blinking lights ;-).

                    > And how does one interface that to a Slug? Can it be done from an i2c bus, or is it necessary to bring out the UART connection from the Slug? And can somebody recommend a suitable sensor/converter for use with that system (I am looking for a temperature resolution of 0.1°C, and an absolute accuracy not too much worse than that).
                    >

                    I use a pre-packaged USB device:
                    http://www.hobby-boards.com/catalog/product_info.php?cPath=23&products_id=1503

                    > I would also like some advice on the path I have been following so far:
                    >
                    > I intended to attach an i2c bus (that seems a well-established hack to the Slug). On that bus there will be assorted LEDs and pushbuttons, an LCD, an EEPROM, and a 4-channel 12-bit A-D converter. I had intended to use LM35DZ temperatures sensors (as manufactured by both MS and Texas). And I had identified an i2c A-D chip from the Farnell website (AD7991) that appeared to have all the required characteristics.
                    >
                    > But I did not check enough. It turned out to be a SOT23 style chip which was about the size of a baby's fingernail :-( . Not nice for building on a breadboard. I looked for a suitable breakout board, but the only available one for an 8-pin SOT23 was in California, and I am in the UK. The only breakout boards readily available in the UK are for 6-pin SOTs (well, there is a possible one from Microchip, but at a ridiculous price).
                    >
                    > So back to the Farnell website for a chip with a larger footprint. But they all seem of be surface mount and with TSSOP or MSOP format, where the pin spacing is still 0.025in (the same as SOT23).
                    >
                    > So can anyone suggest any better chip? I might get away with SOIC format (0.05in spacing). The only chips I can find with good ol' DIL fomat are from Microchip, and they use Yet Another Nonstandard Interface (Microport).
                    >

                    Check out the kits and parts at the supplier I listed above. That will
                    give you some idea about size and nature of the various one-wire chips
                    and devices, and from that you can decide if the one-wire parts are more
                    practical.

                    In terms of the temperature sensors, I needed a network of them, and
                    found that the pre-packaged or kitted parts were all too expensive -- I
                    was paying more for connectors than the parts. So I purchased a dozen
                    of the temperature sensors from a taiwan-based supplier (via eBay).
                    Each part is in a small transistor package, and were very easy to solder
                    to short (8 inches approx) twisted pair.

                    Each "pigtail" was tested, and the network address recorded. I attached
                    a label with the network address to the pigtail as well -- otherwise you
                    have no idea which sensor is which (they are, of course, wired up to
                    the same twisted pair).

                    I wired the building up with ordinary telephone twisted pair, running a
                    length through the first-floor rooms, then dragging it through the
                    crawlspace beneath the building to get a sensor down where the plumbing
                    is at most risk of freezing.

                    I estimate the total cost for that part of the system to be about USD 3
                    per sensor, by the time I was done with the sensors, solder, and
                    telephone wire. Hard to beat that for price.

                    -Mike (mwester)

                    >> On Thu, 2010-04-01 at 13:47 +0000, clerew5 wrote:
                    >>
                    >
                    >
                    >>> --- In nslu2-linux@yahoogroups.com, "Mike Westerhof (mwester)"
                    >>> <mwester@> wrote:
                    >>>
                    >>>
                    >>>> I have a slug installed at an old house I have been working to
                    >>>> refurbish. It uses a network of one-wire sensors to monitor
                    >>>>
                    >>> temperature...
                    >>>
                    >>> Eh? What sort of sensor uses one wire?
                    >>>
                    >
                    >
                    >
                    >
                    > ------------------------------------
                    >
                    > Yahoo! Groups Links
                    >
                    >
                    >
                    >
                    >
                  • clerew5
                    ... Yes, there seems to be some neat stuff there. But I am already well down the i2c route. Actually, I have now reached the conclusion that the easiest way to
                    Message 9 of 16 , Apr 5, 2010
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                      --- In nslu2-linux@yahoogroups.com, Mike Westerhof <mwester@...> wrote:

                      > > But I did not check enough. It turned out to be a SOT23 style chip which was about the size of a baby's fingernail :-( . Not nice for building on a breadboard. I looked for a suitable breakout board, but the only available one for an 8-pin SOT23 was in California, and I am in the UK. The only breakout boards readily available in the UK are for 6-pin SOTs (well, there is a possible one from Microchip, but at a ridiculous price).
                      > >
                      > > So back to the Farnell website for a chip with a larger footprint. But they all seem of be surface mount and with TSSOP or MSOP format, where the pin spacing is still 0.025in (the same as SOT23).
                      > >
                      > > So can anyone suggest any better chip? I might get away with SOIC format (0.05in spacing). The only chips I can find with good ol' DIL fomat are from Microchip, and they use Yet Another Nonstandard Interface (Microport).
                      > >
                      >
                      > Check out the kits and parts at the supplier I listed above. That will
                      > give you some idea about size and nature of the various one-wire chips
                      > and devices, and from that you can decide if the one-wire parts are more
                      > practical.

                      Yes, there seems to be some neat stuff there. But I am already well down the i2c route.

                      Actually, I have now reached the conclusion that the easiest way to embed surface mounted chips (even the very small ones) is to manufacture a one-off PCB. This turns out to be much easier that one might have thought. Google turns up lots of advice. All you need is a laser printer, some suitable transfer paper (old glossy magazines are recommended), and a willingness to handle ferric chloride etch (which is pretty messy stuff by all accounts).
                    • Thomas Cooper
                      It s much easier to buy what you need ready to go from Spark Fun Electronics, or some place similar... They cost about a buck or so. A bottle of ferric cloride
                      Message 10 of 16 , Apr 5, 2010
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                        It's much easier to buy what you need ready to go from Spark Fun Electronics, or some place similar... They cost about a buck or so. A bottle of ferric cloride will cost you more than that.

                        On Mon, Apr 5, 2010 at 4:09 AM, clerew5 <clerew5@...> wrote:
                         


                        --- In nslu2-linux@yahoogroups.com, Mike Westerhof <mwester@...> wrote:

                        > > But I did not check enough. It turned out to be a SOT23 style chip which was about the size of a baby's fingernail :-( . Not nice for building on a breadboard. I looked for a suitable breakout board, but the only available one for an 8-pin SOT23 was in California, and I am in the UK. The only breakout boards readily available in the UK are for 6-pin SOTs (well, there is a possible one from Microchip, but at a ridiculous price).
                        > >
                        > > So back to the Farnell website for a chip with a larger footprint. But they all seem of be surface mount and with TSSOP or MSOP format, where the pin spacing is still 0.025in (the same as SOT23).
                        > >
                        > > So can anyone suggest any better chip? I might get away with SOIC format (0.05in spacing). The only chips I can find with good ol' DIL fomat are from Microchip, and they use Yet Another Nonstandard Interface (Microport).
                        > >
                        >
                        > Check out the kits and parts at the supplier I listed above. That will
                        > give you some idea about size and nature of the various one-wire chips
                        > and devices, and from that you can decide if the one-wire parts are more
                        > practical.

                        Yes, there seems to be some neat stuff there. But I am already well down the i2c route.

                        Actually, I have now reached the conclusion that the easiest way to embed surface mounted chips (even the very small ones) is to manufacture a one-off PCB. This turns out to be much easier that one might have thought. Google turns up lots of advice. All you need is a laser printer, some suitable transfer paper (old glossy magazines are recommended), and a willingness to handle ferric chloride etch (which is pretty messy stuff by all accounts).


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