Introduction: Soil Moisture Content Measurement Using Esp32 and Thingsio.ai Platform

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In this tutorial I am going to explain about reading of the moisture content in the soil by using esp32 and then sending the values into the thingsio.ai IoT cloud platform.

Step 1: COMPONENTS

Hardware Components:

1. esp32 development board

2.Soil sensor

3.Jumper Wires

Software:

1. Arduino IDE

2. Thingsio.ai

Step 2: CONNECTIONS

Soil Moisture Sensor----------------------esp32 Board

VCC---------------------------------------3V3

GND--------------------------------------GND

A0----------------------------------------VP

Step 3: CODING:

#include <WiFi.h>
#include <WiFiMulti.h>
#include<WiFiClientSecure.h>
int count=0,i,m,j,k;
int t;
int sensor_pin = A0;
int value ;
//////////////////////////////////////// ALL DECLARATIONS
for CLOUD //////////////////////////////
const char* host = "api.thingsai.io";                                 // OR host =
devapi2.thethingscloud.com
const char* post_url = "/devices/deviceData";       // OR
/api/v2/thingscloud2/_table/data_ac
const char* time_server =
"baas.thethingscloud.com";            
//this is to convert timestamp
const int httpPort = 80;
const int httpsPort = 443;
const char*  server =
"api.thingsai.io";  // Server
URL
char timestamp[10];
WiFiMulti WiFiMulti;
// Use WiFiClient class to create TCP connections
   WiFiClient client;
/////////////////////////////////////// TIMESTAMP
CALCULATION function///////////////////////////////////////
int GiveMeTimestamp()
{
  unsigned long
timeout = millis();
 // WiFiClient client;
  while
(client.available() == 0)
  {
    if (millis() -
timeout > 50000)
    {
      client.stop();
      return 0;
    }
  }
while (client.available())
      {
        String line =
client.readStringUntil('\r');                   
//indexOf() is a funtion to search for smthng , it returns -1 if not
found
        int pos =
line.indexOf("\"timestamp\"");                       //search for
"\"timestamp\"" from beginning of response got and copy all
data after that , it'll be your timestamp
        if (pos >=
0)                                                     
        {
          int j = 0;
         
for(j=0;j<10;j++)
          {
           
timestamp[j] = line[pos + 12 + j];
          }
        }
      }
}  
////////////////////////////////////////////////////////////////////////////////////////////////////////
void setup()
{
   
Serial.begin(115200);
   
Serial.println("Reading From the Sensor ...");
   delay(2000);
    // We start by
connecting to a WiFi network
    WiFiMulti.addAP("Wifi_name",
"Wifi_Password");
    Serial.println();
    Serial.println();
   
Serial.print("Wait for WiFi... ");
   
while(WiFiMulti.run() != WL_CONNECTED) {
       
Serial.print(".");
        delay(500);
    }
   
Serial.println("");
   
Serial.println("WiFi connected");
    Serial.println("IP
address: ");
   
Serial.println(WiFi.localIP());
    delay(500);
}
void loop() 
{
{
/////////////////////////////////////// SEND THE QUERY AND
RECEIVE THE RESPONSE/////////////////////// 
       value=
analogRead(sensor_pin);
     // value =
map(value,550,0,0,100);
       
Serial.print("Mositure : ");
        
Serial.print(value);
         
Serial.println("%");
          
delay(1000);
 
Serial.print("connecting to ");
 
Serial.println(host);                          //defined upside :-
host = devapi2.thethingscloud.com or 139.59.26.117
///////////////////////////////////// TIMESTAMP CODE SNIPPET
/////////////////////////
Serial.println("inside get timestamp\n");
  if
(!client.connect(time_server, httpPort)) 
  {
    return;                                                       
//*-*-*-*-*-*-*-*-*-*
  }
 
client.println("GET /api/timestamp HTTP/1.1");                            //Whats this part
doing, i didnt get
 
client.println("Host: baas.thethingscloud.com");
 
client.println("Cache-Control: no-cache");
 
client.println("Postman-Token:
ea3c18c6-09ba-d049-ccf3-369a22a284b8");
  client.println();
GiveMeTimestamp();           
            //it'll call the
function which will get the timestamp response from the server
Serial.println("timestamp receieved");
Serial.println(timestamp);
 
Serial.println("inside ThingsCloudPost");
  String PostValue =
"{\"device_id\": 61121695918, \"slave_id\": 2";
        PostValue =
PostValue + ",\"dts\":" +timestamp;
   PostValue =
PostValue +",\"data\":{\"MOIST\":" + value
+"}"+"}";
 
Serial.println(PostValue);
/* create an instance of WiFiClientSecure */
WiFiClientSecure client;
   
Serial.println("Connect to server via port 443");
    if
(!client.connect(server, 443)){
       
Serial.println("Connection failed!");
    } else {
       
Serial.println("Connected to server!");
        /* create HTTP
request */
       
client.println("POST /devices/deviceData HTTP/1.1");
       
client.println("Host: api.thingsai.io");
       
//client.println("Connection: close");
       
client.println("Content-Type: application/json");
        client.println("cache-control:
no-cache");
       
client.println("Authorization: Bearer
eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.IjVhMzBkZDFkN2QwYjNhNGQzODkwYzQ4OSI.kaY6OMj5cYlWNqC2PNTkXs9PKy6_m9tdW5AG7ajfVlY");
       
client.print("Content-Length: ");
        client.println(PostValue.length());
       
client.println();
       
client.println(PostValue);
//////////////////////////////////POSTING the data on to the
cloud is done and now get the response form cloud server//////////////////
 Serial.print("Waiting for response
");
        while
(!client.available()){
            delay(50);
//
           
Serial.print(".");
        }  
        /* if data is
available then receive and print to Terminal */
        while
(client.available()) {
            char c = client.read();
           
Serial.write(c);
        }
        /* if the
server disconnected, stop the client */
        if
(!client.connected()) {
           
Serial.println();
           
Serial.println("Server disconnected");
            client.stop();
        }
    }
Serial.println("//////////////////////    THE END    
/////////////////////");
delay(3000);
}
}

Step 4: OUTPUT:

The Output of the code is shown.

Step 5: GRAPH

This is the graphical representation of the values which are read from the sensor.

Step 6:

Here is the complete video of the project. Thank You.