DIY DIY - Affordable? Soil NPK, pH & EC sensor (NPKPHC-S)

[Bob's Auto's]

Hey fellow DIY's


As you might have guessed from the title, I would like to talk about the NPKPHC-S sensor.
I found this one while window shopping on Ali yesterday and although pricey, it was still 'cheap' considering what it's suppose to be able to measure...

And it's got an RS485 output. I'm not going into the technical specifics in this introductory post, but let's say one could have the sensor at half a mile away and still communicate with it over 2 wires. This is why it's the most commonly used protocol in PLC's and industrial machines.
This also means I can interface this sensor with an Arduino or even better a NodeMCU or other ESP series WiFi enabled device. Oh, the possibilities are giving me goosebumps

The idea is to have this sensor semi wireless. Meaning it still needs to be connected to a power supply. But this can be a USB battery pack as these devices have a USB connection. The device will output the measured values to my Blynk server. And then I can connect to it with my Blynk app on my phone.

I've already made a rudimentary 'test' app on the phone...

And...spent half of the night coding some test-programs for when the sensor arrives... And this my friends, will be the hard part...Waiting until everything arrives...
So, this thread will record the voyage in building this Soil monitor and evaluating if it's any good.


Regards,

Bob

 

[Bob's Auto's]

Well, I did order myself a CO² sensor, but it more then worth it...I guess

After coding all sorts of test programs and coming to the conclusion that an ESP32 would have run out of pins way before I installed half the sensors...I decided on a combination of something old and proven and something new, as it has to be able to connect to the WiFi.

Let me introduce you to the Arduino Mega with WiFi!! Oh yes, all the input and output pins that the Mega has, Wifi thanks to the esp chip on board and loads of hardware upgrades which makes me want to connect as many sensors as I possibly can onto it.

Hope this is clear for you guys as much as for myself as by the time all the parts arrive I've probably forgotten which device connects to which pin...