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Quick Question... — Parallax Forums

Quick Question...

ArchiverArchiver Posts: 46,084
edited 2003-07-03 11:29 in General Discussion
Hi everyone! I'm new to the group, and to the stamp.

I have a quick question. Has anyone done a temperature data logger. With say
256k of EEPROM? Maybe two sensors?

I've been looking at the DS1516 and it's pretty cool but logging for a year
would be really handy. Just set it and forget it [noparse]:)[/noparse]

If anyone has some Websites or info they would like to point me to that would be
great!

Thanks in advance!
Tim

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-07-02 22:06
    I'm currently working on my first "real" BS2 project. I use two thermistors
    to sense data (one "local" and one "remote"), set up as a voltage divider
    with a 1K resistor (the thermistors are 1k at 25C). I ave a lookup table
    stored in the EEPROM of the stamp to convert the voltage I get via an ADC to
    temperature, also interfaced to an RTC, then save this data to an EEPROM
    (right now, I use an I2C EEPROM with only 2048KB to log the data, but
    replacing with more memory would be simple. I have yet to develop the
    software for the PC to download the data, but everything else works. I have
    an LED display to display time, and the temperatures as well. The software
    can log temps in increments of 1 minutes to 60 minutes....

    While this seems uninteresting to my friends, It does work, and I built it.
    Very satisfying!

    Steve


    Original Message
    From: "Tim Hart" <tim.hart@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Wednesday, July 02, 2003 10:42 PM
    Subject: [noparse][[/noparse]basicstamps] Quick Question...


    > Hi everyone! I'm new to the group, and to the stamp.
    >
    > I have a quick question. Has anyone done a temperature data logger. With
    say 256k of EEPROM? Maybe two sensors?
    >
    > I've been looking at the DS1516 and it's pretty cool but logging for a
    year would be really handy. Just set it and forget it [noparse]:)[/noparse]
    >
    > If anyone has some Websites or info they would like to point me to that
    would be great!
    >
    > Thanks in advance!
    > Tim
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-02 22:23
    I know the feeling. My friends and wife are completely uninterested. That's
    one of the reasons I joined the group, so I can chat with people who understand
    what I'm saying!

    Sounds like your almost done, getting the data back into the PC might not be so
    hard. They have DAQ software that can store your Debug output for ya.

    My project may end up in my house. Sensor1 outside, #2 in the attic, #3 near
    the air return, #4 on a vent and maybe one on the Water heater. With a year of
    data logging.....is that to much to ask? [noparse]:)[/noparse] Maybe I'll start out small with
    just one or two sensors [noparse]:)[/noparse]

    And I agree with you, building it yourself is far more satisfying. Cheaper
    too!!

    Thanks,
    Tim

    >>> zman97211@y... 07/02/03 04:06PM >>>
    I'm currently working on my first "real" BS2 project. I use two thermistors
    to sense data (one "local" and one "remote"), set up as a voltage divider
    with a 1K resistor (the thermistors are 1k at 25C). I ave a lookup table
    stored in the EEPROM of the stamp to convert the voltage I get via an ADC to
    temperature, also interfaced to an RTC, then save this data to an EEPROM
    (right now, I use an I2C EEPROM with only 2048KB to log the data, but
    replacing with more memory would be simple. I have yet to develop the
    software for the PC to download the data, but everything else works. I have
    an LED display to display time, and the temperatures as well. The software
    can log temps in increments of 1 minutes to 60 minutes....

    While this seems uninteresting to my friends, It does work, and I built it.
    Very satisfying!

    Steve


    Original Message
    From: "Tim Hart" <tim.hart@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Wednesday, July 02, 2003 10:42 PM
    Subject: [noparse][[/noparse]basicstamps] Quick Question...


    > Hi everyone! I'm new to the group, and to the stamp.
    >
    > I have a quick question. Has anyone done a temperature data logger. With
    say 256k of EEPROM? Maybe two sensors?
    >
    > I've been looking at the DS1516 and it's pretty cool but logging for a
    year would be really handy. Just set it and forget it [noparse]:)[/noparse]
    >
    > If anyone has some Websites or info they would like to point me to that
    would be great!
    >
    > Thanks in advance!
    > Tim
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >


    To UNSUBSCRIBE, just send mail to:
    basicstamps-unsubscribe@yahoogroups.com
    from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.


    Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-02 23:23
    There's a nice little EEProm, the 24LC256. Its 30k memory with 100,000 write
    life. It has an I2C interface which is pretty easy to use - lots of I2C
    examples around.

    One gotcha for these memories is that you have to watch auto-incrementing
    write addresses. First time I used one it seemed to work great when doing
    short tests but when I left it running and went away, the data would be
    filled with seemingly spurious values (my line graph had regular jumps in
    it).

    Took me a while but I noticed it was happening every 128th byte (or was it
    256th?). I was writing 13 bytes every log event and taking advantage of the
    auto-incrementing adresses. The address counter doesn't appear to be able to
    roll over in the middle of a write. So if the write starts at the 125th
    byte, the 126th and 127th would be put in the proper place but the 128th
    would end up nowhere near where I wanted.

    My solution was to change my log format and save 16 bytes at a time which
    divided evenly and never invoked the roll-over problem.

    The other way around it is to supply the address for each byte written.
    Slower and a bit more work but safe.

    Oh yes, one more thing that I didn't find readily apparent when using I2C -
    Writes are pretty straight forward as shown in this pseudo-code:

    I2CStart /*Initiate conversation*/
    I2CWriteByte EEpromWriteAddress /* Tell it which chip and which mode *
    I2CAddressHighByte /* Address to write to */
    I2CAddressLowByte /*Address to write to */
    I2CWriteByte var1, Ack /* Write a byte - Ack if its not the last byte */
    I2CWriteByte var2, Ack /* Write a byte - Ack if its not the last byte */
    I2CWriteByte var3, Nack /* Last byte don't Ack */
    I2CStop /*End conversation */

    Reads are a bit different. You have to do a write conversation in order to
    send the starting address then start another conversation using a read
    conversation - without issuing a stop.

    I2CStart /*Initiate conversation*/
    I2CWriteByte EEpromWriteAddress /* Tell it which chip and which mode *
    I2CAddressHighByte /* Address to write to */
    I2CAddressLowByte /*Address to write to */
    I2CStart /* Start again, don't use Stop! */
    I2CWriteByte EEpromReadAddress /* Tell it which chip and which mode *
    I2CReadByte var1, Ack /* Write a byte - Ack if its not the last byte */
    I2CReadByte var2, Ack /* Write a byte - Ack if its not the last byte */
    I2CReadByte var3, Nack /* Last byte don't Ack */
    I2CStop /*End conversation */



    Original Message
    From: "Tim Hart" <tim.hart@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Wednesday, July 02, 2003 2:23 PM
    Subject: Re: [noparse][[/noparse]basicstamps] Quick Question...


    > I know the feeling. My friends and wife are completely uninterested.
    That's one of the reasons I joined the group, so I can chat with people who
    understand what I'm saying!
    >
    > Sounds like your almost done, getting the data back into the PC might not
    be so hard. They have DAQ software that can store your Debug output for ya.
    >
    > My project may end up in my house. Sensor1 outside, #2 in the attic, #3
    near the air return, #4 on a vent and maybe one on the Water heater. With a
    year of data logging.....is that to much to ask? [noparse]:)[/noparse] Maybe I'll start out
    small with just one or two sensors [noparse]:)[/noparse]
    >
    > And I agree with you, building it yourself is far more satisfying.
    Cheaper too!!
    >
    > Thanks,
    > Tim
    >
    > >>> zman97211@y... 07/02/03 04:06PM >>>
    > I'm currently working on my first "real" BS2 project. I use two
    thermistors
    > to sense data (one "local" and one "remote"), set up as a voltage divider
    > with a 1K resistor (the thermistors are 1k at 25C). I ave a lookup table
    > stored in the EEPROM of the stamp to convert the voltage I get via an ADC
    to
    > temperature, also interfaced to an RTC, then save this data to an EEPROM
    > (right now, I use an I2C EEPROM with only 2048KB to log the data, but
    > replacing with more memory would be simple. I have yet to develop the
    > software for the PC to download the data, but everything else works. I
    have
    > an LED display to display time, and the temperatures as well. The software
    > can log temps in increments of 1 minutes to 60 minutes....
    >
    > While this seems uninteresting to my friends, It does work, and I built
    it.
    > Very satisfying!
    >
    > Steve
    >
    >
    >
    Original Message
    > From: "Tim Hart" <tim.hart@h...>
    > To: <basicstamps@yahoogroups.com>
    > Sent: Wednesday, July 02, 2003 10:42 PM
    > Subject: [noparse][[/noparse]basicstamps] Quick Question...
    >
    >
    > > Hi everyone! I'm new to the group, and to the stamp.
    > >
    > > I have a quick question. Has anyone done a temperature data logger.
    With
    > say 256k of EEPROM? Maybe two sensors?
    > >
    > > I've been looking at the DS1516 and it's pretty cool but logging for a
    > year would be really handy. Just set it and forget it [noparse]:)[/noparse]
    > >
    > > If anyone has some Websites or info they would like to point me to that
    > would be great!
    > >
    > > Thanks in advance!
    > > Tim
    > >
    > >
    > >
    > > To UNSUBSCRIBE, just send mail to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > > from the same email address that you subscribed. Text in the Subject
    and
    > Body of the message will be ignored.
    > >
    > >
    > > Your use of Yahoo! Groups is subject to
    http://docs.yahoo.com/info/terms/
    > >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-07-03 11:29
    I put together a datalogger not long ago, that logged temperature
    and stored the results in a 24c02.

    Only 256bytes of EEPROM, but the principle is basically the
    same for your needs?

    Take a look at it here, and see if it gives you any ideas:
    http://www.lennard.net.nz/lennardelectronics/electronics/ad.html
    #datalogger2

    cheers,

    Ben,

    Windy Wellington,
    New Zealand.


    --- In basicstamps@yahoogroups.com, "Tim Hart"
    <tim.hart@h...> wrote:
    > Hi everyone! I'm new to the group, and to the stamp.
    >
    > I have a quick question. Has anyone done a temperature data
    logger. With say 256k of EEPROM? Maybe two sensors?
    >
    > I've been looking at the DS1516 and it's pretty cool but logging
    for a year would be really handy. Just set it and forget it [noparse]:)[/noparse]
    >
    > If anyone has some Websites or info they would like to point
    me to that would be great!
    >
    > Thanks in advance!
    > Tim
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