The ESP8266 WiFi Module is a self contained SOC with integrated TCP/IP protocol stack that can give any microcontroller access to your WiFi network. The ESP8266 is capable of either hosting an application or offloading all Wi-Fi networking functions from another application processor. Each ESP8266 module comes pre-programmed with an AT command set firmware, meaning, you can simply hook this up to your Arduino device and get about as much WiFi-ability as a WiFi Shield offers (and that’s just out of the box)! The ESP8266 module is an extremely cost effective board with a huge, and ever growing, community.This module has a powerful enough on-board processing and storage capability that allows it to be integrated with the sensors and other application specific devices through its GPIOs with minimal development up-front and minimal loading during runtime. Its high degree of on-chip integration allows for minimal external circuitry, including the front-end module, is designed to occupy minimal PCB area. The ESP8266 supports APSD for VoIP applications and Bluetooth co-existance interfaces, it contains a self-calibrated RF allowing it to work under all operating conditions, and requires no external RF parts. refrence link
Realtime Temperature and humidity mnitoring circuit is designed which uses DHT11 temp and humidity sendor and an ESP8266 cheap wifi module. this module does not need any arduino board or any external component. only 3.3 V regulator is required with 5V power supply. this circuit will send the real time data (temperature and humidity) with interval of about 2 seconds to iotalways.com web server.
ESP8266 can be directly programmed in arduino IDE by selecting the correct board"Generic ESP8266 Module" and com port. the code is given below, DHT11 sensor is connected with 5V power while the data out pin of dht11 is connected to GPIO 2 of ESP8266 Module via voltage dropout resistors.
you need to register with iotalways.com to get an api key, replace the api keyy with the one given in code, program the ESP module in arduino IDE then data will be uploaded to web server automatically with the interval you define in your code.
Dht11 passthrough mode