💬 Soil Moisture Sensor

[alowhum]

@dbemowsk Changing the Chirp's I2C address is very easy actually.

#include <I2CSoilMoistureSensor.h>
#include <Wire.h>

I2CSoilMoistureSensor sensor(0x20);

// connect the reset pin (5) of the Chirp to a pin on your Arduino. It will create a small reset signal. This tells the chirp it should not be a stand-alone ensor, but an I2C connected one. If it receives I1C data shortyl after a reset (few seconds), then it will understand.
int resetPin = 4;

void setup() {
  pinMode(resetPin, OUTPUT); 
  delay(1000);
  digitalWrite(resetPin, HIGH);       // sets the digital pin 13 on
  delay(100);                  // waits for a second
  digitalWrite(resetPin, LOW);        // sets the digital pin 13 off
  delay(1000);
  Wire.begin();
  Serial.begin(9600);

  sensor.begin(); // reset sensor
  delay(1000); // give some time to boot up
  Serial.print("I2C Soil Moisture Sensor Address: ");
  Serial.println(sensor.getAddress(),HEX);
  Serial.print("Sensor Firmware version: ");
  Serial.println(sensor.getVersion(),HEX);
  Serial.println();

  Serial.print("Change address to 0x21 ...");
  if (sensor.setAddress(0x21,true)) // set Sensor Address to 0x21 and reset
    Serial.println("... DONE");
  else
    Serial.println("... ERROR");
  Serial.println();
}

/*loop scans I2C bus and displays foud addresses*/
void loop() {
  byte error, address;
  int nDevices;

  Serial.println("Scanning...");

  nDevices = 0;
  for(address = 1; address < 127; address++ ) {
    // The i2c_scanner uses the return value of
    // the Write.endTransmisstion to see if
    // a device did acknowledge to the address.
    Wire.beginTransmission(address);
    error = Wire.endTransmission();

    if (error == 0) {
      Serial.print("I2C device found at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.print(address,HEX);
      Serial.println("  !");

      nDevices++;
    }
    else if (error==4) {
      Serial.print("Unknow error at address 0x");
      if (address<16)
        Serial.print("0");
      Serial.println(address,HEX);
    }
  }
  if (nDevices == 0)
    Serial.println("No I2C devices found\n");
  else
    Serial.println("done\n");

  delay(3000);           // wait 5 seconds for next scan
}

The default address is 0x20. So my idea is to just keep scanning, and if I find a 0x20 Chirp, then I change its I2C address to 0x21 and higher. Repeat as necessary until all 0x20 devices are gone.

The only thing I'm not sure about is if this is possible. If I can pick them off one by one this way.

[dbemowsk]

@alowhum That is nice. Some I2C devices have it hard coded and do not allow this from my understanding.

[alowhum]

@dbemowsk True. But it's another reason why I think the Chirp devices are pretty great soil sensors.

[dbemowsk]

@alowhum :+1:

[UL7AAjr]

@alowhum
Not sure I2C is a good idea excepting case all sensors inside one room. It can be used just for testing to make it easy. As usual RS485 used to connect any sensors to nework. And there is Modbus protocol over RS485 that enable to use not only custom sensors, but kind of devices can be usefull in automatic systems. For example pump controllers, valve controllers....

So.. no good perspecrives to go

[alowhum]

Well, the Chirp doesn't support that protocol, so..
It does have a mini arduino inside. Perhaps you could reprogram it. Then I will happily have a look ;-)

https://wemakethings.net/chirp/

[UL7AAjr]

No reason to reprogramm. There is I2C wired outside of sensor instead of UART. And some IC necessary to drive RS485.

Would be easy to use custom adapter over the sensor with only two IC on board, some MCU and MAX485 (or analog).

[alowhum]

I found another, simpler sensor on Aliexpress.

https://www.aliexpress.com/item/NEW-Capacitive-soil-moisture-sensor-not-easy-to-corrode-wide-voltage-wire-for-arduino/32832538686.html

[รอเรือ]

@robkuipers

Your code will fail compiling in Arduino 1.8.5 (mysensors 2.2.0) with the following errors:

/mnt/data/Dropbox/UTV/Arduino/SoilMoisture/SoilMoisture.ino: In function 'void before()':
/mnt/data/Dropbox/UTV/Arduino/SoilMoisture/SoilMoisture.ino:112:114: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11
   sensors[0] = { SENSOR1_ROD1_DIGITAL, SENSOR1_ROD1_ANALOG, SENSOR1_ROD2_DIGITAL, SENSOR1_ROD2_ANALOG, -1, false };
                                                                                                                  ^
/mnt/data/Dropbox/UTV/Arduino/SoilMoisture/SoilMoisture.ino:112:14: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11
   sensors[0] = { SENSOR1_ROD1_DIGITAL, SENSOR1_ROD1_ANALOG, SENSOR1_ROD2_DIGITAL, SENSOR1_ROD2_ANALOG, -1, false };
              ^
/mnt/data/Dropbox/UTV/Arduino/SoilMoisture/SoilMoisture.ino:116:114: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11
   sensors[1] = { SENSOR2_ROD1_DIGITAL, SENSOR2_ROD1_ANALOG, SENSOR2_ROD2_DIGITAL, SENSOR2_ROD2_ANALOG, -1, false };
                                                                                                                  ^
/mnt/data/Dropbox/UTV/Arduino/SoilMoisture/SoilMoisture.ino:116:14: warning: extended initializer lists only available with -std=c++11 or -std=gnu++11
   sensors[1] = { SENSOR2_ROD1_DIGITAL, SENSOR2_ROD1_ANALOG, SENSOR2_ROD2_DIGITAL, SENSOR2_ROD2_ANALOG, -1, false };
              ^

So the following code need tobe changed to something valid

sensors[0] = { SENSOR1_ROD1_DIGITAL, SENSOR1_ROD1_ANALOG, SENSOR1_ROD2_DIGITAL, SENSOR1_ROD2_ANALOG, -1, false };

	sensors[1] = { SENSOR2_ROD1_DIGITAL, SENSOR2_ROD1_ANALOG, SENSOR2_ROD2_DIGITAL, SENSOR2_ROD2_ANALOG, -1, false };

I'm not a c++ guy so I can't tell what needs to be done. Maybe you or someone else would like to help out?

Cheers!

EDIT: After removing the file platform.txt for solving another problem (as suggested here) The problem above vanished. So strange. But it works now so... :sunglasses: :sunglasses: :sunglasses:

[รอเรือ]

I've found that measuring soil moisture by the electrical resistance is not a trivial task.

If the probe is put into compact soil containing no mold, you'll typically get a high reading even at very low moisture levels. It will most likely always stay within the span of 90-100%.

However if the probe is put into pure mold, the readings will range between 0% to 100%.

My conclusion is that measuring directly in the soil is very unpredictable. A better solution might be to surround the probe with some material that adapts the ambient humidity from whatever kind of soil it's put into.

[alowhum]

Perhaps the capacitive sensors are more useful.

[mfalkvidd]

I guess it depends on the soil. Resistive measurements works well for all my plants.

[UL7AAjr]

This post is deleted!

[UL7AAjr]

@mfalkvidd It depends from mineral composition of soil. I buld capacitive sensor with additional electrodes to measure salinity of soil with resistive method (it measures the resistance of soil to alternating current). So, while value of capacitive sensor stable and let say 50%, value of resistive can be critically changed by adding few milliliters of water with fertilizer. Capacitive value will be chaged only to 60% e.g.

It's not a good idea to use resistive sensor, especcialy measuring resistance to direct current.

[mfalkvidd]

@ul7aajr could you expand on why is it not a good idea? I've been using my sensors for almost 3 years without noticing any problem.

[UL7AAjr]

Sure. At first, I'm very surprised that your resistive sensor in soil still not destroyed under corrosion especially when the current flows. All my experiments with such sensors have been stuck many years ago. May be a miss sometihing, just show me your sensors after three years in soil? And again, it's a basic phisical things, that the conductivity of the soil depends on the mineral composition. I have already said more than once that there is possible to get a "negative" conductivity of the soil, something like effect of the battery.

[mathieu44444]

Hello,
I start with mysensors and I do not know much about programming. Is there a possibility to have 7 soil moisture sensor on one or two arduino mini pro.
Thank you

[alowhum]

My sketch handles 6. Feel free to use it. It uses analog capacitive sensors. They cost about 3 euro.

I would recommend getting an Arduino Nano with an Expansion board. Then you don't need to solder anything.
https://www.aliexpress.com/item/Free-shipping-Nano-328P-IO-wireless-sensor-expansion-board-for-XBEE-and-NRF24L01-Socket-for-arduino/32298692903.html

/**
 * The MySensors Arduino library handles the wireless radio link and protocol
 * between your home built sensors/actuators and HA controller of choice.
 * The sensors forms a self healing radio network with optional repeaters. Each
 * repeater and gateway builds a routing tables in EEPROM which keeps track of the
 * network topology allowing messages to be routed to nodes.
 *
 * Created by Henrik Ekblad <henrik.ekblad@mysensors.org>
 * Copyright (C) 2013-2015 Sensnology AB
 * Full contributor list: https://github.com/mysensors/Arduino/graphs/contributors
 *
 * Documentation: http://www.mysensors.org
 * Support Forum: http://forum.mysensors.org
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 *******************************
 *
 * DESCRIPTION
 * 
 * This node can measure the moisture of 6 different plants. It uses the cheap 'capacitive analog 
 * moisture sensor' that you can get for about 3 dollars an Aliexpress or eBay. For example:
 * https://www.aliexpress.com/item/Analog-Capacitive-Soil-Moisture-Sensor-V1-2-Corrosion-Resistant-Z09-Drop-ship/32858273308.html
 * 
 * Each plant' moisture value can also be responded to individually, either by turning on an LED (wire that to the plan, and you can see which one is thirsty) or, if you want, per-plant automated irrigation by connecting a little solenoid..
 * 
 * Todo: Allow the controller to set the threshold values for each plant individually. Unfortunately, Domoticz doesn't support this yet :-(
 * 
 */

//#define MY_SIGNING_SIMPLE_PASSWD "changeme"
#define MY_SPLASH_SCREEN_DISABLED                       // saves a little memory.
//#define MY_DISABLE_RAM_ROUTING_TABLE_FEATURE          // saves a little memory.

#define MY_NODE_ID 60                                   // Optional. Sets fixed id with controller.
#define MY_PARENT_NODE_ID 0                             // Optional. Sets fixed id for controller.
#define MY_PARENT_NODE_IS_STATIC                        // Optional. Sets fixed id for controller.

#define MY_TRANSPORT_WAIT_READY_MS 5000                 // try connecting for 5 seconds. Otherwise just continue.

// Enable debug prints to serial monitor
//#define MY_DEBUG

// Enable and select radio type attached
#define MY_RADIO_NRF24
//#define MY_RADIO_NRF5_ESB
//#define MY_RADIO_RFM69
//#define MY_RADIO_RFM95

#define MY_RF24_PA_LEVEL RF24_PA_LOW                    // Low power radio setting works better with cheap Chinese radios.

#include <MySensors.h>

#define NUMBEROFSENSORS 6                               // How many sensors are connected?

#define DRYNESSTHRESHOLD 45                             // minimum moisture level that is still ok. A lower value will trigger LED/irrigation.

uint32_t SLEEPTIME = 60;                                // Sleep time between the sending of data (in SECONDS). Maximum is 254 seconds. Change "byte" to "int" further down in the code if you want more time between sending updates.
unsigned long lastTimeChecked = 0;

MyMessage msg(0, V_LEVEL);

void before()
{

  for (byte i = 3; i < NUMBEROFSENSORS + 3; i++){             // Set the LED (or irrigation vales) to their initial position.
    pinMode(i, OUTPUT);
    digitalWrite(i, LOW);
  }
  
}


void presentation()
{
	// Send the sketch version information to the gateway and Controller
	sendSketchInfo(F("Plant Sensorium"), F("1.2"));

  // present the sensors
  for (byte i=0; i<NUMBEROFSENSORS ; i++) {
    present(i, S_MOISTURE, i); // the last i gives the controller a name, in this case the number of the sensor.
  }

}

void setup()
{
  Serial.begin(115200);
  delay(1000);
  
  Serial.println(F("Hello world. Warming up the sensors (15 seconds)."));

  delay(15000);
  
}

void loop()
{

  static byte measurementCounter = 0;                     // Counts the measurements that are done, once per second.
  uint32_t currentMillis = millis();                      // The millisecond clock in the main loop.

  if (currentMillis - lastTimeChecked > 1000) {           // Internally, the moisture values are checked every second.
    lastTimeChecked = currentMillis;
    
    Serial.println(F("__________"));
    
    for (int i=0; i<NUMBEROFSENSORS; i++) {               // loop over all the sensors.
      byte shiftedDigitalPin = i + 3;
    	int16_t moistureLevel = (1023-analogRead(i))/10.23;
      Serial.print(i);
      Serial.print(F(" mosture level: "));
    	Serial.println(moistureLevel);
      Serial.print(F("- output pin: "));
      Serial.println(shiftedDigitalPin);      
      Serial.print(F("- irrigation/LED state is "));
      Serial.println(digitalRead(shiftedDigitalPin));

      if(digitalRead(shiftedDigitalPin) == HIGH){                         // outputs the LED/irrigation status via serial. This code can be removed.
        Serial.print(F("- currently watering until "));
        Serial.println(DRYNESSTHRESHOLD + 10);
      }

      if (moistureLevel < DRYNESSTHRESHOLD){              // if the plant doesn' have enough water, turn on the LED/water.
        Serial.print(F("- moisture level is below "));
        Serial.println(DRYNESSTHRESHOLD);
        digitalWrite(shiftedDigitalPin, HIGH);
      }else if (moistureLevel >= DRYNESSTHRESHOLD + 10){   // turn of the water/led if the plant is wet enough.
        digitalWrite(shiftedDigitalPin, LOW);
      }

      if(measurementCounter < NUMBEROFSENSORS){           // During the first 6 seconds the script will send updated data.
        if(measurementCounter == i){                      // it sends sensor 0 at second 0. Sensor 1 at second 1, etc. This keeps the radio happy.
          Serial.println(F("- sending data."));
          send(msg.setSensor(i).set(moistureLevel));
        }
      }
      if(measurementCounter > SLEEPTIME){ // If enough time has passed, the counter is reset, and new data is sent.
        measurementCounter = 0;
      }else{
        measurementCounter++;
      }
    }
    
  }
}

[mathieu44444]

I command and I try. Thank you very much

[alowhum]

@mathieu44444 My pleasure. Good luck.