Soil Moisture Monitoring

Author: Andreea Paiu

Introduction

The purpose of this project is to monitor a plant's soil moisture and notice us when the moisture exceeds the set limits.

Hardware Description

The components used for the project were the following:

ESP32 Dev Board
Hygrometre sensor Module - soil humidity
Wires

The electronic schema:

Software Description

Used Libraries:

#include <WiFi.h>
#include <AsyncTCP.h>
#include <ESPAsyncWebServer.h>
#include <Firebase_ESP_Client.h>
#include "addons/TokenHelper.h"
#include "addons/RTDBHelper.h"
#include <InfluxDbClient.h>
#include <InfluxDbCloud.h>

Set-ups:

Firebase

void setup_firebase() {
  config.api_key = API_KEY;
 
  config.database_url = DATABASE_URL;

  if (Firebase.signUp(&config, &auth, "", "")){
    Serial.println("ok");
    signupOK = true;
  }
  else{
    Serial.printf("%s\n", config.signer.signupError.message.c_str());
  }
 
  config.token_status_callback = tokenStatusCallback;
 
  Firebase.begin(&config, &auth);
  Firebase.reconnectWiFi(true);
}

Routing

void setup_routing() {
  server.on("/", HTTP_GET, MainPage); 
  server.on("/read_moisture", HTTP_GET, SoilMoisture);  
  server.on("/update_low_limit_slide", HTTP_GET, UpdateLowLimitSlide);
  server.on("/update_high_limit_slide", HTTP_GET, UpdateHighLimitSlide);
  server.on("/read_low_limit", HTTP_GET, ReadLowLimit);
  server.on("/read_high_limit", HTTP_GET, ReadHighLimit);
  server.onNotFound(notFound);
  server.begin();
}

Wifi

WiFi.mode(WIFI_STA);             
  WiFi.begin(ssid, password);
  while(WiFi.waitForConnectResult() != WL_CONNECTED){
    Serial.print(".");
    delay(100);
  }

Tasks

xTaskCreatePinnedToCore(
                    Task1code,   /* Task function. */
                    "Task1",     /* name of task. */
                    10000,       /* Stack size of task */
                    NULL,        /* parameter of the task */
                    1,           /* priority of the task */
                    &Task1,      /* Task handle to keep track of created task */
                    0);          /* pin task to core 0 */                  
  xTaskCreatePinnedToCore(
                    Task2code,   /* Task function. */
                    "Task2",     /* name of task. */
                    10000,       /* Stack size of task */
                    NULL,        /* parameter of the task */
                    1,           /* priority of the task */
                    &Task2,      /* Task handle to keep track of created task */
                    1);          /* pin task to core 1 */
}

We use both cores: First core get data and sent them in InfluxDB

void Task1code( void * pvParameters ){
   Serial.println(xPortGetCoreID());
  for(;;){
    sensor.clearFields();
    sensor_analog = analogRead(sensor_pin);
    _moisture = ( 100 - ( (sensor_analog/4095.00) * 100 ) );
    sensor.addField("value", _moisture);
    Serial.print("Writing: ");
    Serial.println(client.pointToLineProtocol(sensor));

    if (!client.writePoint(sensor)) {
      Serial.print("InfluxDB write failed: ");
      Serial.println(client.getLastErrorMessage());
    }
  
    Serial.print("Moisture = ");
    Serial.print(_moisture);
    Serial.println("%");
    delay(1000);  
  }
}

Second core add limit value in Firebase and check values

void Task2code( void * pvParameters ){
  String low_val = String(0);
  String high_val = String(100);
  for(;;){
  Serial.print("Task2 running on core ");
  Serial.println(xPortGetCoreID());
  String low_val = String(0);
  
  if (Firebase.RTDB.getInt(&fbdo, "/limit/low")) {
    if (fbdo.dataType() == "int") {
      low_val = fbdo.intData();
      Serial.println(low_val);
    }
  }
  
  if (Firebase.RTDB.getInt(&fbdo, "/limit/high")) {
    if (fbdo.dataType() == "int") {
      high_val = fbdo.intData();
      Serial.println(high_val);
    }
  }
  Serial.println(_moisture);
  Serial.println("comparatie");
  digitalWrite(led2, LOW);
  if(_moisture > high_val.toInt() || _moisture < low_val.toInt())
    digitalWrite(led2, HIGH);
  delay(1500); 
  }
}