ESP8266 - WiFi Module

20 March 2018 - 0 Comments

ESP8266 WiFi Module

ESP8266 Pinout

ESP8266 Pin Configuration

Pin Number	Pin Name	Alternate Name	Normally used for	Alternate purpose
1	Ground	-	Connected to the ground of the circuit	-
2	TX	GPIO – 1	Connected to Rx pin of programmer/uC to upload program	Can act as a General purpose Input/output pin when not used as TX
3	GPIO-2	-	General purpose Input/output pin	-
4	CH_EN	-	Chip Enable – Active high	-
5	GPIO - 0	Flash	General purpose Input/output pin	Takes module into serial programming when held low during start up
6	Reset	-	Resets the module	-
7	RX	GPIO - 3	General purpose Input/output pin	Can act as a General purpose Input/output pin when not used as RX
8	Vcc	-	Connect to +3.3V only

ESP8266-01 Features

Low cost, compact and powerful Wi-Fi Module
Power Supply: +3.3V only
Current Consumption: 100mA
I/O Voltage: 3.6V (max)
I/O source current: 12mA (max)
Built-in low power 32-bit MCU @ 80MHz
512kB Flash Memory
Can be used as Station or Access Point or both combined
Supports Deep sleep (<10uA)
Supports serial communication hence compatible with many development platform like Arduino
Can be programmed using Arduino IDE or AT-commands or Lua Script

ESP8266 Equivalents

ESP-12 (Has more GPIO pins that support ADC, PWM, SPI etc)

Alternative for ESP8266-01

ESP32 (more powerful and standalone module)

ESP8266-01 Boot Option

GPIO – 0	GPIO – 2	Mode	Used For
High	High	Flash Mode	Run the program that is already uploaded to the module
Low	High	UART Mode	Programming mode- to program using Arduino or any serial communication

Where to use ESP8266-01

The ESP8266 is a very user friendly and low cost device to provide internet connectivity to your projects. The module can work both as a Access point (can create hotspot) and as a station (can connect to Wi-Fi), hence it can easily fetch data and upload it to the internet making Internet of Things as easy as possible. It can also fetch data from internet using API’s hence your project could access any information that is available in the internet, thus making it smarter. Another exciting feature of this module is that it can be programmed using the Arduino IDE which makes it a lot more user friendly. However this version of the module has only 2 GPIO pins (you can hack it to use upto 4) so you have to use it along with another microcontroller like Arduino, else you can look onto the more standalone ESP-12 or ESP-32 versions. So if you are looking for a module to get started with IOT or to provide internet connectivity to your project then this module is the right choice for you.

How to use the ESP8266 Module

There are so many methods and IDEs available to with ESP modules, but the most commonly used on is the Arduino IDE. So let us discuss only about that further below.

The ESP8266 module works with 3.3V only, anything more than 3.7V would kill the module hence be cautions with your circuits. The best way to program an ESP-01 is by using the FTDI board that supports 3.3V programming. If you don’t have one it is recommended to buy one or for time being you can also use an Arduino board. One commonly problem that every one faces with ESP-01 is the powering up problem. The module is a bit power hungry while programming and hence you can power it with a 3.3V pin on Arduino or just use a potential divider. So it is important to make a small voltage regulator for 3.31v that could supply a minimum of 500mA. One recommended regulator is the LM317 which could handle the job easily. A simplified circuit diagram for using the ESP8266-01 module is given below

ESP8266 Example Circuit

The switch SW2 (Programming Switch) should be held pressed to hold the GPIO-0 pin to ground. This way we can enter into the programming mode and upload the code. Once the code is released the switch can be released.