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  • Author Author: feiticeir0
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[Pool Water Monitoring] #12 Architecture Design #3: Arduino MKR 1300 WAN data sender

feiticeir0

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Hi all ! Hope everyone is safe and sound. This is the part of the project that will collect and send the data to the receiver part.

It will monitor:

  • Water temperature using the DS18b20 High temperature probe
  • Nutrients of the water using the TDS probe
  • Water PH using the PH probe
  • Environment temperature, humidity and pressure using the AM2302 sensor

Hardware

  • Arduino MKR 1300 WAN
  • TDS sensor
  • PH sensor
  • AM2302
  • 2x batteries

Here's a schematic, so far, of it:

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Everything will be fitted inside of the Hammond enclosure with the transparent lid.

To outside of the enclosure, in one hole and using one of the Hammond cable glands will be three cables:

  • Antenna, in 868MHz (Europe frequency) to connect to the Arduino
  • High temperature sensor probe
  • TDS sensor probe

The PH probe is another problem. The probe cannot stay inside of the water all the time.

I'm still waiting on the probe to arrive, but I know that the sensor and the probe are connected through a BNC connector. 

A hole will be made, big enough for the BNC connector and silicone will be used to seal it and prevent leaks to inside the enclosure.

Anytime the PH is to be measured, the connector will be inserted and a PH reading will be taken.  In the code, measures will be made if the PH probe is not connected.

Here are some photos of everything inside - but still unassembled -

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Next steps will be assemble everything, calibrate the TDS probe and start coding. When the PH probe arrives,  it will be added to the mix, calibrated and start working.

My next post will be about all of the values that will be measured and what they mean .

Stay safe .

  • in reply to m.ratcliffe

    Hi !

    I forgot to add to the schematics the waterproof ds18b20 temperature probe. It will measure it - because to measure ECs, temperature is always important... This time of year, way far from 25 ºC ! Smiley

  • in reply to m.ratcliffe

    It would appear that the edit comment button has been moved...... 

    When people are talking about water quality and EC/TDS, they are often discussing the relative EC at 25'C.   I pulled a few lines for the correction and converting to ppm from a previous project, in this case EC is your raw EC reading and EC25 is the corrected EC taking into account temperature. Hope its helpful. 

    //*********** Converting to ppm [Learn to use EC it is much better**************//
// Hana      [USA]        PPMconverion:  0.5
// Eutech    [EU]          PPMconversion:  0.64
//Tranchen  [Australia]  PPMconversion:  0.7
// Why didnt anyone standardise this?
    float PPMconversion=0.7;

    //*************Compensating for temperature ************************************//
//The value below will change depending on what chemical solution we are measuring
//0.019 is generaly considered the standard for plant nutrients [google "Temperature compensation EC" for more info
float TemperatureCoef = 0.019; //this changes depending on what chemical we are measuring




    //*************Compensating For Temperaure********************//
EC25  =  EC/ (1+ TemperatureCoef*(Temperature-25.0));
ppm=(EC25)*(PPMconversion*1000);

  • Might be a good idea to also measure the pool water temperature? 

    It is no doubt useful information in general to have about a pool. Temperature also plays quite an important role on TDS/EC and correcting for temperature will be needed for reasonably trustworthy TDS readings.