Basics of WiFi and its implementation

Wi-Fi is the radio signal sent from a wireless router to a nearby device, which translates the signal into data you can see and use. The device transmits a radio signal back to the router, which connects to the internet by wire or cable.

What does Wi-Fi stand for?

Ironically, it doesn’t stand for anything. Wi-Fi is often thought to be short for Wireless Fidelity but there is no such thing. The term was created by a marketing firm because the wireless industry was looking for a user-friendly name to refer to some not so user-friendly technology known as IEEE 802.11. And the name stuck.

Although Wi-Fi is typically used to access the internet on portable devices like smartphones, tablets, or laptops, in actuality, Wi-Fi itself is used to connect to a router or other access point, which in turn provides internet access. Wi-Fi is a wireless connection to that device, not the internet itself. It also provides access to a local network of connected devices, which is why you can print pictures wirelessly or look at a video feed from Wi-Fi connected cameras with no need to be physically connected to them.

The typical range of a standard Wi-Fi network can reach up to 100 meters in the open air.  Typically, ranges of 10-35 meters are more common. The strength of the antenna and the frequency broadcast can also impact the effective range of the network. Higher frequencies like 5GHz and 60GHz have far shorter effective ranges than 2.4GHz.

ESP8266 Module

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 WiFi 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.

ESP8266 comes with capabilities of

  • 2.4 GHz Wi-Fi (802.11 b/g/n, supporting WPA/WPA2),
  • general-purpose input/output (16 GPIO),
  • Inter-Integrated Circuit (I²C) serial communication protocol,
  • analog-to-digital conversion (10-bit ADC)
  • Serial Peripheral Interface (SPI) serial communication protocol,
  • I²S (Inter-IC Sound) interfaces with DMA(Direct Memory Access) (sharing pins with GPIO),
  • UART (on dedicated pins, plus a transmit-only UART can be enabled on GPIO2), and
  • pulse-width modulation (PWM).

Connection of Wifi module for programming:-

It employs a 32-bit RISC CPU based on the Tensilica Xtensa L106 running at 80MHz (or overclocked to 160 MHz). It has a 64KB boot ROM, 64KB instruction RAM and 96KB data RAM. External flash memory can be accessed through SPI.

ESP8266 module is low cost standalone wireless transceiver that can be used for end-point IoT developments.

Module comes with different pin availability options like,

  • ESP-01 comes with 8 pins (2 GPIO pins) – PCB trace antenna. (shown in above figure)
  • ESP-02 comes with 8 pins, (3 GPIO pins) – U-FL antenna connector.
  • ESP-03 comes with 14 pins, (7 GPIO pins) – Ceramic antenna.
  • ESP-04 comes with 14 pins, (7 GPIO pins) – No ant.


ESP8266 easily available on many websites, some links are given below…