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Another Life kit springs to life

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  • erd_6502
    Hi, all, I just got my Life board working. I haven t managed to get organized enough for my summer Digikey order (I still need a few parts for other Gizmos),
    Message 1 of 3 , Sep 7, 2007
      Hi, all,

      I just got my Life board working. I haven't managed to get organized
      enough for my summer Digikey order (I still need a few parts for other
      Gizmos), so I'm missing most of the PSU parts. In the meantime, I
      attached a 2.5A +5V PSU to the LM2940T-5.0 pads, and, via a single
      diode, an 9VAC PSU to the bridge rectifier spot, in the manner I
      described here on the list a few weeks ago. Once I got TxD and RxD
      sorted out on my serial cable, I was able to use FLIP on the Atmel
      AT89C51RD2 and fire up the stock firmware. The unit goes through what
      I have to expect is the stock initialization screen (a large Copyright
      symbol, Bob and Dan's initials, the word "LIFE" diagonally across the
      display, etc.) then it enters Life Demo mode. I don't have a
      universal remote or a Sharp remote here, but the Demo mode seems to
      work properly.

      I haven't installed the chip yet, but I did populate the optional
      sockets and resistors for a DS1307. I've been contemplating how to
      add a DS1624 or a DS1631 or similar, on the same bus as the DS1307,
      and I think I've found a way to do it without modifying the board -
      take a 16-pin machined pin socket, then run some jumper wires from
      Vcc, GND, SCL and SDA from the 8 pins that map on top of the DS1307
      socket over to the _other half_ of the 16-pin socket, in a pattern
      that maps to the pinout of the chosen temp chip. Plug the 16-pin
      socket into the 8-pin DS1307 socket, plug a DS1307 on top it's normal
      8-pin footprint, then plug the temp chip into the other half of the
      16-pin socket, then learn how to get an 8051-family MCU to read temps.

      I did contact Dallas/Maxim about, specifically, an i2c temp chip. The
      answer was that they do have a few chips that will work on an i2c bus,
      but are listed as "2-wire serial". While I don't doubt that the Life
      MPU could talk to one of these 2-wire serial chips, what's not as
      clear to me is if they will play nice with a DS1307. Either way, I
      was going to start with some DS1307 code and worry about temps later.

      To that end, one thought I had was to default a DS1307-equipped Life
      to a clock mode rather than Life Demo Mode, or perhaps to use one of
      the 56 bytes of NVRAM on the DS1307 to remember the last requested
      mode. If anyone out there has been thinking about i2c peripheral
      enhancements to the stock firmware, I'd like to exchange ideas.

      In the meantime, what I realize I really need is a hunk of red plexi,
      and a case. Until then, I'll just have the Life board sitting on my
      desk to elicit comments.

      -ethan
    • keycat02
      ... Hi Ethan. The voltage regulator on the life board gets pretty hot, so you may want to mount the temperature sensor outside the case! Cheers, John R.
      Message 2 of 3 , Sep 7, 2007
        > I did contact Dallas/Maxim about, specifically, an i2c temp chip. The
        > answer was that they do have a few chips that will work on an i2c bus,
        > but are listed as "2-wire serial". While I don't doubt that the Life
        > MPU could talk to one of these 2-wire serial chips, what's not as
        > clear to me is if they will play nice with a DS1307. Either way, I
        > was going to start with some DS1307 code and worry about temps later.
        >

        Hi Ethan. The voltage regulator on the life board gets pretty hot, so
        you may want to mount the temperature sensor outside the case!
        Cheers, John R.
      • Ethan Dicks
        ... Ah... good point. I don t have a regulator on-board yet, and I don t have an enclosure, so I haven t run into that particular issue, but I m sure I would
        Message 3 of 3 , Sep 7, 2007
          On 9/7/07, keycat02 <keycat02@...> wrote:
          > > I did contact Dallas/Maxim about, specifically, an i2c temp chip. The
          > > answer was that they do have a few chips that will work on an i2c bus,
          > > but are listed as "2-wire serial".
          >
          > Hi Ethan. The voltage regulator on the life board gets pretty hot, so
          > you may want to mount the temperature sensor outside the case!

          Ah... good point. I don't have a regulator on-board yet, and I don't
          have an enclosure, so I haven't run into that particular issue, but
          I'm sure I would have.

          I still think it'll be easy to tap the 4 signal necessary from a 16
          socket stuffed into an 8-pin socket, but I suppose one could also
          stack two 8-pin sockets together and attach the essential 4 wires
          in-between the sockets, then run them a few inches away from the board
          so the i2c sensor could be outside the case.

          For software development, at least, I think I'll still whip up the
          16-pin socket.

          Thanks for pointing out the obvious issue, though.

          -ethan
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