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Arduino Forum Help with WiFi web server analog input code
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  • wifi
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Related

Help with WiFi web server analog input code

Former Member
Former Member over 11 years ago

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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  • vish
    0 vish over 11 years ago

    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.

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  • Former Member
    0 Former Member over 11 years ago in reply to vish

    Hi Vishnu,

     

    As shown below, I printed out analogSamplesAverage twice to see what its value is in the Serial Monitor:

     

    http://pastebin.com/embed_js.php?i=1sGEeTY3

     

    Both times, analogSamplesAverage prints as 0. I also tried replacing the map function that I used with the formula manual calculation, as shown below, but analogSamplesAverage still prints as 0 both times:


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


    So, it seems that something is going wrong with the running average/smoothing functionality of the code. 

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  • vish
    0 vish over 11 years ago in reply to Former Member

    Hi Michele,

    I think I didn't understood your problem correctly? Could you please tell me what value you are expecting  for analogSampleAverage? I was thinking it must be zero under unloaded condition.

    also check whether your analog pin is grounded( either the sensor output is grounded or whether and analog track is grounded)?

     

    and one more thing..

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

    in this formula, all the RHS variables are of integer type. So there is a possible chance of type casting error. Check that also.

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  • Former Member
    0 Former Member over 11 years ago in reply to vish

    Hi everyone,

     

    Just wanted to let you all know that I did get my code working as it should by making the web server code a subroutine of the load cell code. Everything works well now!

     

    Thanks again for all the help!

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  • vish
    0 vish over 11 years ago in reply to Former Member

    wow...great image

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  • vish
    0 vish over 11 years ago in reply to Former Member

    wow...great image

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