ESP8266EX

The ESP8266EX (Figure 1.1) is a single-chip microcontroller developed by Espressif (https://espressif.com/). It can be used to develop low-power, highly-integrated Wi-Fi solutions especially for mobile devices, wearable electronics, and the Internet of Things (IoT) applications. The main advantage of ESP8266EX is that it can give any microcontroller access to a Wi-Fi network. As an example, it can offload all Wi-Fi networking functions for Arduino just like the Arduino Wi-Fi shield:

Figure 1.1: ESP8266EX chip

The chip has the following great features:

• Small size (5 mm x 5 mm)
• Requires minimal external circuitry
• Wide temperature range (-40°C to + 125°C)
• All-in-one small package -SoC (integrates a 32-bit Tensilica MCU, standard digital peripheral interfaces, antenna switches, RF balun, power amplifier, low-noise receive amplifier, filters, and power management modules)
• Low power consumption

ESP-01

ESP-01 is a small Wi-Fi module based on Espressif ESP8266EX that can give any microcontroller access to a Wi-Fi network. The ESP-01 module (Figure 1.2) is the basic and the most popular board of the ESP8266 module family. You should have an ESP8266 ESP-01 module to understand the basics of ESP8266 and build robotics projects.

This is a list of vendors that typically stock the ESP-01 modules:

• SparkFun Electronics: https://www.sparkfun.com/products/13678
• Adafruit Industries: https://www.adafruit.com/product/2282
• Electrodragon: http://www.electrodragon.com/product/esp8266-wi07c-wifi-module/

Figure 1.2: The original ESP8266 ESP-01. Image courtesy of SparkFun Electronics (https://www.sparkfun.com)

The original ESP8266 ESP-01 has the following features:

• Offloads all Wi-Fi networking functions from another application's processor
• Self-hosting of applications
• Only four pins interface, VCC-3V3, GND, TX, and RX
• 1 MB (8 MB) flash memory
• Pre-programmed AT command set firmware
• Supports APSD for VoIP applications and Bluetooth co-existence interfaces

Here is a list of all the ESP8266 boards of the ESP8266 module family at the time of writing:

• ESP-01
• ESP-02
• ESP-03
• ESP-04
• ESP-05
• ESP-06
• ESP-07
• ESP-08
• ESP-09
• ESP-10
• ESP-11
• ESP-12
• ESP-12F
• ESP-12-E/Q
• ESP-12S
• ESP-13
• ESP-14

Board features and connections

The top of the ESP-01 board consist of the following things:

• An ESP8266EX chip—Offloading all Wi-Fi networking functions
• A Berg Micro BG25Q80A 1518 flash chip—Serial Peripheral Interface (SPI) flash memory
• A printed Wi-Fi antenna—Transmitting and receiving Wi-Fi signals

Figure 1.3: ESP-01 top view

Connections

The original ESP8266 ESP-01 board has eight pins and comes without headers. You can solder regular wires with pins, but if you want to use it with a breadboard, you should attach headers:

Figure 1.4: ESP-01 pinout

• GPIO0: Connects to pin 3 of the ESP8266
• GPIO2: Connects to pin 5 of the ESP8266
• TX: This is the transmitting line that connects to RX of another device
• RX: This is the receiving line that connects to TX of another device
• 3V: This accepts regulated 3.3V DC from a regulator to power the board
• GND: The ground pin
• CH_PD: Chip select
• RST: The reset pin