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Help with WiFi web server analog input code

Former Member

Hi all,

 

I have written some code to display readings from an analog input (load cell from a digital scale) in my browser through a web server. However, when I have nothing on my load cell, the browser displays a weight value of -500 rather than 0. I know that the code I'm using for the load cell works, so the problem arises from how I've combined the load cell code with the WiFi web server code. I have tried to correct the issue, but I haven't been able to figure it out at all. Any help or ideas would be much appreciated. Thank you!

 

My Code


http://pastebin.com/embed_js.php?i=FsyCGy9Y

 

Sources


WiFi Web Server code: Tutorial: Arduino wi-fi server to Google Drive storage | Daviom

 

Load Cell code: https://github.com/Airtripper/load-cell-test/blob/master/load_cell_test.ino

 


The WiFi Web Server code uses a temperature sensor as the analog input and includes code for that purpose. I replaced the temperature sensor code with the Load Cell code.



Attachments:
Arduino_to_Google_Spreadsheet_7_14.ino.zip
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  • 0

    Hi,

    What is the value of 'loadAdjustment'? In github, it's set to 0. is it same in your case also?

    And one more point. You could print analogSamplesAverage and do a manual calculation of map function just to ensure that it is working fine.

    This is the formula for manual calculation :

         float loadGrams = map(analogSamplesAverage, analogLow, analogHigh, loadLow, loadHigh);

    wil become

         loadGrams = ( analogSamplesAverage - analogLow ) * ( loadHigh - loadLow) / ( analogHigh - analogLow ) + loadLow

    formula from here.

  • 0 in reply to vish

    Hi Vishnu,

     

    Thanks for the suggestion about checking out analogSamplesAverage to see if something is going wrong with that calculation. I will look into that later today when I get home.


    loadAdjustment     is essentially a way to zero the scale if there is a container on the scale that you don't want to weigh (e.g. if I have a container that weighs 5 grams that holds items weighing 40 grams, and I just want to record the weight of the items, I would set loadAdjustment equal to 5 so loadGrams would be 40 and not 45). Since I'm not using a container of any kind, loadAdjustment should be set to 0.

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  • 0 in reply to vish

    Hi Vishnu,

     

    Thanks for the suggestion about checking out analogSamplesAverage to see if something is going wrong with that calculation. I will look into that later today when I get home.


    loadAdjustment     is essentially a way to zero the scale if there is a container on the scale that you don't want to weigh (e.g. if I have a container that weighs 5 grams that holds items weighing 40 grams, and I just want to record the weight of the items, I would set loadAdjustment equal to 5 so loadGrams would be 40 and not 45). Since I'm not using a container of any kind, loadAdjustment should be set to 0.

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