ESP8266 WIFI MODULE: In this modern world, the WiFi technology has removed the distances, in which the electronic devices are used, which are connected to the wireless Lan (WLAN) network, by using at 2.4 gigahertz or 5 gigahertz radio frequency bands. The Lan network provides the facility of password protection and also allows the device to use the network which is within the range of that device. In this advanced technology different types of modules are used, which have different features. Here we would explain the AT commands of ESP8266 WIFI module details but before explaining the AT commands, first of all, we would explain the brief history of WiFi.
The history of WIFI was started in 1985 when the united states FCC used the 900 MHZ frequency band without a license. Because the frequency band of this technology was very low therefore in beginning, this technology was only assumed for home appliances such as a microwave oven. After that, in 1991 the NCR and AT&T corporation invented a first wireless product that’s name was Wave Lan, which was used for the cashier system. In this fragmented market the research was continued, finally, the first WIFI system was introduced in 1997, which was the prototype communication system.
ESP8266 WIFI Module
The ESP8266 WIFI module is basically a complete WIFI solution, which has self-contained integrated TCP/IP protocol stack that can be easily connected to the microcontroller for gaining access to any WiFi network. We can connect this module to any microcontroller like pic microcontroller, Arduino and we can use it as a stand-alone device. For connecting this module to any WI-FI network, you can just upload the program to this WiFi module and can use to send data to the Web server or getting HTTP requests. I will talk more about it in coming tutorials.
Pin Configuration of ESP 8266 WI-FI Module
There are many ESP8266 Wifi modules available in marker ranging from ESP-01 to ESP-12. But in this tutorial, we are using ESP-01. AT commands are the same for all these ESP modules. The ESP8266 WIFI module consists of two rows of eight pins. The pin configuration diagram is shown in figure below
According to the figure 2 the pin 1, which is GND the ground pin which is directly connected to the ground for power on this module. The pins 2 and 3, which are the GPIO 2 and GPIO 0, these pins decided in which mode the module would be a start-up, in other words, these are mode selected pins. The pins 4 and 5, which are RX and TX, these pins are used for communication purposes and program the module. The pin 6 which is CH_PD, it is called chip power down pin. The pin 7 which is RST pin and this pin is used for reset the module. The pin 8 which is VCC pin and is used to power on the module. The operating voltage of this module is 3.3 volts, which are directly connected to the ground pin(GND) and VCC pin.
Instruction Commands of ESP 8266 Module
The wireless WI-FI ESP 8266 module is drive through serial interfacing with Arduino or any type of modules. The standard AT commands are used for this purposes, which are almost twelve.
(1) AT: This type of command is used to test the startup function of WI-FI module. The response would be ok, against this command if everything is ok.
(2) AT+RST: This type of command is used for reset the WI-FI module when it is in working condition. The response would be ok, when reset the module.
(3)AT+GMR: This type of AT command is used to check the version of AT command and we used SDK version of AT command in this type of WI-FI module.
(4) AT+GSLP: This type of AT command is used to invoke the module from sleep mode, in other words this command is used for wake -up the module.
(5) ATE:This type of command is used for echo sound, means that, when this command is entered then the echo send back to the sender.
(6) AT+RESTORE: This type of command is used for restore factory setting means, when this command is entered then all the parameters are reset automatically.
(7) AT+UART: This type of command is used for set the UART configuration and writes the new configuration in flash means, it is used for setting the default parameters.
(8) AT+UART_CUR:This type of command is used for set the current UART configuration and does not write to the flash.
(9) AT+UART_DEF: This type of command is used for set the UART configuration and save it in flash.
(10) AT+SLEEP:This type of command is used to the set the module in sleep mode.
(11) AT+RFPOWER:This type of command is used for set the maximum value of power for ESP 8266 RXTF, but it is not precise.
(12) AT+RFVDD:This type of command is used for set the maximum value of power for ESP 8266 RXTX according to the VDD33.
Interfacing of ESP8266 Module with arduino
The ESP8266 WI-FI module cannot directly connect to the computer for connecting this with computer an interfacing device is must require. The interfacing device may be the microcontroller or Arduino board. By using the serial port of audio the ESP 8266 module can be connect to the computer. The Arduino board runs on 5 volts and ESP 8266 run on 3.3 volte. Before connection, first you have make sure the regulated required voltages. These voltages can regulate for TX/RX pins through the IC CD 4050 shown in figure.
Two serial ports are used for this connection, one serial port is used for the connection between Arduino and ESP 8266 for sending the command AT to ESP8266 and other one is used for the connection between Arduino and computer for typing the command AT on computer key board.
Check these tutorials on Esp8266 wifi module