ESP8266 ESP-01 & DHT11 Sensor
Humidity (%) : 44.00 Temperature (°C) : 29.00 Temperature (°F) : 84.20
tNow : 4292
A DHT Temperature and Humidity Sensor, $11 for 5 pieces (on 2017.07.03), soldered to an ESP8266 ESP-01, with code to connect to an access point, and on request, show the data shown above (with a 30 second refresh) in a browser. Pretty handy if you just want to provide 5 Vdc with a USB cable to the programmer (or 3.3 Vdc using wires). http://www.elec-cafe.com/ shows all the magic on how to do the temperature and humidity part.
// http://www.elec-cafe.com/temperature-sensor-on-the-web-with-esp8266-and-ds18b20/
// 2017.07.03: reset:'!' and info:'?'
// Author: Speed Muller
#include <ESP8266WiFi.h>
#include <DHT11.h>
#define VERSION "2017.07.03 ESP-01 DHT"
int counter;
unsigned int tNow;
unsigned int tPrevious;
WiFiServer server( 80 );
DHT11 dht11( PIN );
void setup( ) {
Serial.begin( 115200 );
delay( 10 );
Serial.println( VERSION );
WiFi.mode( WIFI_STA );
Serial.println( );
Serial.print( "Connecting: " );
Serial.println( ssid );
WiFi.begin( ssid, password );
while( WiFi.status( ) != WL_CONNECTED ) {
delay( 500 );
Serial.print( "." );
} // while not connected
Serial.println( "" );
Serial.println( "WiFi ready!" ); // Start the server server.begin( );
Serial.println( "Server ready!" );
counter = 0;
tPrevious = tNow = millis( );
} // setup( )
void info( ) {
Serial.println( );
Serial.println( VERSION );
Serial.print( "SSID: " );
Serial.println( ssid );
Serial.print( "IP Address: " );
Serial.println( WiFi.localIP( ) );
} // info
void loop( ) {
tNow = millis( );
if ( tNow - tPrevious > DELAYTIME ) {
tPrevious = tPrevious + DELAYTIME; // Serial.println( "all the needed info" );
} // if time to print on Serial port
WiFiClient client = server.available( );
client.println( "HTTP/1.1 200 OK" );
client.println( "Content-Type: text/html" );
client.println( "Connection: close" ); // the connection will be closed after completion of the response
client.println( "Refresh: 30" ); // refresh the page automatically every 30 sec
client.println( );
client.println( "<!DOCTYPE html>" );
client.println( "<html xmlns='http://www.w3.org/1999/xhtml'>" );
client.println( "<head>\n<meta charset='UTF-8'>" );
client.println( "<title>ESP8266 Temperature & Humidity</title>" );
client.println( "</head>\n<body>" );
client.println( VERSION ); // client.println all your information here...
client.print( "</body>\n</html>" );
delay( DHT11_RETRY_DELAY ); // delay for reread
if( Serial.available( ) > 0 ) {
int inByte = Serial.read( );
if ( inByte == '!' )
ESP.reset( ); // reset
if ( inByte == '?' )
info( );
} // if Serial.available( )
} // loop( )