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    fisherba

    @fisherba

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    Latest posts made by fisherba

    • RE: Polynomial fits not working in Colorimeter-v05

      @Will-Dickson Oh, silly us! The curve makes a u-shape, so we needed to drop the pH 4.74 value. Now the polynomial fitting works.

      posted in Colorimeter
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      fisherba
    • Polynomial fits not working in Colorimeter-v05

      @Will-Dickson ... we had a discussion about this in the "Additional tests for colorimeter..." thread and I think I was able to get polynomial fits to work in May-June of 2017 after you packaged v05. But now @maddiehankard and our group at St Thomas have created another pH curve that we are playing with and v05 will only let us use a linear fit (not even a second or third order polynomial... and we need 4th order). Our x-y data are below.

      # 2018-04-11 Hankard, Wolf, University of St.Thomas 
      # Colorimeter Data
      # LED white
      # -----------------------------
      # pH | Absorbance
      4.74  0.26
      5.45  0.21
      5.69  0.22
      6.36  0.25
      7.00  0.34
      7.43  0.44
      8.16  0.55
      9.17  0.62
      
      posted in Colorimeter
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      fisherba
    • RE: Additional tests for colorimeter (pH, alkalinity, calcium hardness, etc.)

      @Will-Dickson Thank you! I very much appreciate your help!

      posted in Colorimeter
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      fisherba
    • RE: Additional tests for colorimeter (pH, alkalinity, calcium hardness, etc.)

      Hi @Will-Dickson, I haven't noticed a bitbucket update in the downloads, and I'm afraid I don't have sufficient Python experience to update it myself. Keep me posted and I look forward using the updated version. Thanks!

      posted in Colorimeter
      F
      fisherba
    • RE: Additional tests for colorimeter (pH, alkalinity, calcium hardness, etc.)

      @Will-Dickson

      There isn't an error message. When I select 4th order and hit the plot button, nothing happens. But I choose linear, 2nd order, or 3rd order it works fine. Same data I posted, same that you used. I'm using that Mac OS software version 4, which appeared to be the current version when I looked yesterday.

      (Thanks so much for your responsiveness!)

      posted in Colorimeter
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      fisherba
    • RE: Additional tests for colorimeter (pH, alkalinity, calcium hardness, etc.)

      @Will-Dickson

      Hmm... the colorimeter software won't let me fit beyond 3rd order.

      pH curve screen shot

      posted in Colorimeter
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      fisherba
    • Software retain serial address?

      The address for the serial port always resets to /dev/tty.usbmodem upon opening the colorimeter software. I have looked through the arduino sketches, but do not see a place to designate the port name. Can someone direct me to this? Most of the time the device will be used on one computer, so I would like to change this default.

      posted in Colorimeter
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      fisherba
    • RE: Additional tests for colorimeter (pH, alkalinity, calcium hardness, etc.)

      Thanks @Will-Dickson! I also just discovered that I have to select the fit type before plotting and it all works. Doing this should help @briansone get around the issue of the plot trying to intercept with (0,0).

      posted in Colorimeter
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      fisherba
    • RE: Additional tests for colorimeter (pH, alkalinity, calcium hardness, etc.)

      @briansone

      Are you willing to share the API results (bromothymol blue)?

      I have pH calibration for API pH 6.0-7.6 and API High Range pH 7.4 to 8.8. The curves are non-linear (polynomial), especially for the high range. I am new to IO Rodeo Forum and I am wondering if there are discussions regarding non-linear calibrations (I looked and didn't find any).

      Here's our calibration:
      2016-04-27
      Colorimeter Data
      K.Jin, A.Aufdenkampe, B.Fisher
      LED red
      API pH 6.0-7.6 bromothymol blue
      pH | Absorbance
      5.8 0.00
      6.0 0.02
      6.4 0.07
      6.8 0.24
      7.2 0.40
      7.6 0.56
      7.8 0.65
      8.0 0.69

      posted in Colorimeter
      F
      fisherba