Here we will use 9v Battery for power supply. We will need 7805 Voltage Regulator IC to get 9V. Then from 7805 IC, feed it to arduino.

Connect the Arduino’s 3v3 (3.3V) output to ESP8266. The ESP8266 works with 3.3V and not 5V, so this is necessary.

Connect the RXD pin of the Arduino to the RX pin of the ESP8266.Connect the TXD pin of the Arduino to the TX pin of the ESP. When we want two things to talk to each other over serial, we connect the TX pin of one to the RX of the other (send goes to receive and the opposite). Here we do not have the Arduino talk to the ESP8266 though, our computer is talking to it via the Arduino.

Connect the RES or RESET pin, When you ground the reset pin, the Arduino works as a dumb USB to serial connector, which is what we want to talk to the ESP8266.

Finally add a button at power supply.

In the Arduino IDE, you don’t need to choose a board, as we’re not uploading anything to the ESP8266. Just choose the right port in the Tools menu and go to Tools → Serial Monitor. Then simply set your baud rate to 115200 (the default ESP8266 firmware uses it) and your line endings to Both NL & CR.And since we talked about the CH_PD pin, remember that if you want to flash the ESP8266 you should connect the GPIO0 pin.

We are doing I2C connection here as per the circuit Diagram.

Link: https://github.com/Infineon/DPS310-Pressure-SensorTo install the DPS310 pressure sensor library in the Arduino IDE, please go now to Sketch > Include Library > Add .ZIP Library... in the Arduino IDE and navigate to the downloaded .ZIP file of this repository. The library will be installed in your Arduino sketch folder in libraries and you can select as well as include this one to your project under Sketch > Include Library> IFX_DPS310.

Link: https://github.com/witnessmenow/arduino-google-maps-api

#include "SoftwareSerial.h"
String ssid ="yourSSID";
String password="yourPassword";
SoftwareSerial esp(6, 7);// RX, TX
String data;
String server = "yourServer"; // www.example.com
String uri = "yourURI";// our example is /esppost.php
int DHpin = 8;//sensor pin
byte dat [5];
String temp ,hum;
void setup() {
pinMode (DHpin, OUTPUT);
esp.begin(9600);
Serial.begin(9600);
reset();
connectWifi();
}
//reset the esp8266 module
void reset() {
esp.println("AT+RST");
delay(1000);
if(esp.find("OK") ) Serial.println("Module Reset");
}
//connect to your wifi network
void connectWifi() {
String cmd = "AT+CWJAP=\"" +ssid+"\",\"" + password + "\"";
esp.println(cmd);
delay(4000);
if(esp.find("OK")) {
Serial.println("Connected!");
}
else {
connectWifi();
Serial.println("Cannot connect to wifi"); }
}
byte read_data () {
byte data;
for (int i = 0; i < 8; i ++) {
if (digitalRead (DHpin) == LOW) {
while (digitalRead (DHpin) == LOW); // wait for 50us
delayMicroseconds (30); // determine the duration of the high level to determine the data is '0 'or '1'
if (digitalRead (DHpin) == HIGH)
data |= (1 << (7-i)); // high front and low in the post
while (digitalRead (DHpin) == HIGH);
// data '1 ', wait for the next one receiver
}
} return data; }
void start_test () {
digitalWrite (DHpin, LOW); // bus down, send start signal
delay (30); // delay greater than 18ms, so DHT11 start signal can be detected
digitalWrite (DHpin, HIGH);
delayMicroseconds (40); // Wait for DHT11 response
pinMode (DHpin, INPUT);
while (digitalRead (DHpin) == HIGH);
delayMicroseconds (80);
// DHT11 response, pulled the bus 80us
if (digitalRead (DHpin) == LOW);
delayMicroseconds (80);
// DHT11 80us after the bus pulled to start sending data
for (int i = 0; i < 4; i ++)
// receive temperature and humidity data, the parity bit is not considered
dat[i] = read_data ();
pinMode (DHpin, OUTPUT);
digitalWrite (DHpin, HIGH);
// send data once after releasing the bus, wait for the host to open the next Start signal
}
void loop () {
start_test ();
// convert the bit data to string form
hum = String(dat[0]);
temp= String(dat[2]);
data = "temperature=" + temp + "&humidity=" + hum;// data sent must be under this form //name1=value1&name2=value2.
httppost();
delay(1000);
}
void httppost () {
esp.println("AT+CIPSTART=\"TCP\",\"" + server + "\",80");//start a TCP connection.
if( esp.find("OK")) {
Serial.println("TCP connection ready");
} delay(1000);
String postRequest =
"POST " + uri + " HTTP/1.0\r\n" +
"Host: " + server + "\r\n" +
"Accept: *" + "/" + "*\r\n" +
"Content-Length: " + data.length() + "\r\n" +
"Content-Type: application/x-www-form-urlencoded\r\n" +
"\r\n" + data;
String sendCmd = "AT+CIPSEND=";//determine the number of caracters to be sent.
esp.print(sendCmd);
esp.println(postRequest.length() );
delay(500);
if(esp.find(">")) { Serial.println("Sending.."); esp.print(postRequest);
if( esp.find("SEND OK")) { Serial.println("Packet sent");
while (esp.available()) {
String tmpResp = esp.readString();
Serial.println(tmpResp);
}
// close the connection
esp.println("AT+CIPCLOSE");
}
}}