ESP32-JSON

ESP32-JSON

Aim:

To interface Wi-Fi module with ESP32 to send data to server using RDL ESP32 Development board.

Description:

Interfacing wi-fi module to send data to the server using ESP32microcontroller.

Hardware required:

ESP32-Microcontroller development board.

Pin connection:

Procedure:

1.        Connect the USB cable to the ESP32 development board.

2.        Open Arduino IDE .Select DOIT ESP32 DEVKIT V1in boards and select COM port.

3.        Verify the program and upload it.

4.        Now you can see wifi connected along with the IP address on the serial monitor.

5.     To check the inserted values of gas and temperature use the server address and check it on        

        the browser.

   

Program:

/*

*     This sketch sends data via HTTP POST requests to data.sparkfun.com service.

*

*     You need to get streamId and privateKey at data.sparkfun.com and paste them

*     below. Or just customize this script to talk to other HTTP servers.

*

*/

#include <WiFi.h>

char ssid[]                        = "your ssid"; char password[] = "your password";

const char* host = "varmatrix.com";

const char* streamId                       = "....................................................... ";

const char* privateKey = ".......................................................................... ";

//http://varmatrix.com/surendrardl/nitk/getone/insert.php? WiFiClient esp32client;

void setup() { Serial.begin(115200); delay(10);

// We start by connecting to a WiFi network

Serial.println(); Serial.println(); Serial.print("Connecting to "); Serial.println(ssid);

/* Explicitly set the ESP8266 to be a WiFi-client, otherwise, it by default,

would try to act as both a client and an access-point and could cause network-issues with your other WiFi-devices on your WiFi-network. */

//WiFi.mode(WIFI_STA);

WiFi.begin(ssid, password);

while (WiFi.status() != WL_CONNECTED) { delay(500);

Serial.print(".");

}

Serial.println(""); Serial.println("WiFi connected"); Serial.println("IP address: "); Serial.println(WiFi.localIP());

}

int value = 0;

 void loop() {

String url="/surendrardl/nitk/getone/insert.php?"; String jason_string="";

char cmd=0;

while(cmd!=13)

{

if (Serial.available()) { cmd=Serial.read();

//        Serial.write(cmd); if(cmd!=13)

jason_string+=cmd;

}

}

while(Serial.available()>0) {Serial.read();}

Serial.print("connecting to ");

Serial.println(host);

// Use WiFiClient class to create TCP connections const int httpPort = 80;

if (!esp32client.connect(host, httpPort)) { Serial.println("connection failed"); return;

}

// We now create a URI for the request

//String              url="/energyconsumption/insert.php?one=1&two=3&three=2";

Serial.print("Requesting URL:");

Serial.println(url);

//String jason_string="{\"gas\":\"40\",\"temp\":\"70\"}";

// This will send the request to the server esp32client.print(String("POST ") + url + " HTTP/1.0\r\n" +

"Host: " + host + "\r\n" + "Accept: *" + "/" + "*\r\n" +

"Content-Length: " + jason_string.length() + "\r\n" + "Content-Type: application/json\r\n" +

"\r\n" + jason_string

+ "\r\n");

unsigned long timeout = millis(); while (esp32client.available() == 0) {

if (millis() - timeout > 5000) { Serial.println(">>> Client Timeout !"); esp32client.stop();

return;

}

}

// Read all the lines of the reply from server and print them to Serial while(esp32client.available()){

String line = esp32client.readStringUntil('\r');

Serial.print(line);

}

Serial.println();

// Serial.println("closing connection");

}

Output:

1.    Open serial monitor you can see Wi-Fi connected along with IP address

Insert { “gas”:”40” , “temperature”:”70” } in the serial monitor and press enter.

2. Enter http://varmatrix.com/sudrendrerdl/nitk/postone/postportal.html in your browser.