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 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
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
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