The Internet of Things with ESP8266

What is the "Internet of things"?

The Internet of things (IoT) is the network of everyday objects — physical things embedded with electronics, software, sensors, and connectivity enabling data exchange. Basically, a little networked computer is attached to a thing, allowing information exchange to and from that thing. Be it lightbulbs, toasters, refrigerators, flower pots, watches, fans, planes, trains, automobiles, or anything else around you, a little networked computer can be combined with it to accept input (especially object control) or to gather and generate informational output (typically object status or other sensory data). This means computers will be permeating everything around us — ubiquitous embedded computing devices, uniquely identifiable, interconnected across the Internet. Because of low-cost, networkable microcontroller modules, the Internet of things is really starting to take off.

What is ESP8266?

The Chips

The ESP8266 series, or family, of Wi-Fi chips is produced by Espressif Systems, a fabless semiconductor company operating out of Shanghai, China. The ESP8266 series presently includes the ESP8266EX and ESP8285 chips.

ESP8266EX (simply referred to as ESP8266) is a system-on-chip (SoC) which integrates a 32-bit Tensilica microcontroller, standard digital peripheral interfaces, antenna switches, RF balun, power amplifier, low noise receive amplifier, filters and power management modules into a small package. It provides capabilities for 2.4 GHz Wi-Fi (802.11 b/g/n, supporting WPA/WPA2), general-purpose input/output (16 GPIO), Inter-Integrated Circuit (I²C), analog-to-digital conversion (10-bit ADC), Serial Peripheral Interface (SPI), I²S interfaces with DMA (sharing pins with GPIO), UART (on dedicated pins, plus a transmit-only UART can be enabled on GPIO2), and pulse-width modulation (PWM). The processor core, called "L106" by Espressif, is based on Tensilica's Diamond Standard 106Micro 32-bit processor controller core and runs at 80 MHz (or overclocked to 160 MHz). It has a 64 KiB boot ROM, 32 KiB instruction RAM, and 80 KiB user data RAM. (Also, 32  KiB instruction cache RAM and 16 KiB ETS system data RAM.) External flash memory can be accessed through SPI. The silicon chip itself is housed within a 5 mm × 5 mm Quad Flat No-Leads package with 33 connection pads — 8 pads along each side and one large thermal/ground pad in the center.

ESP8285 is a variation of ESP8266 with 1 MiB of embedded flash memory.

Now, if you're looking for something a bit more capable, check out ESP32 — it has more memory, more GPIO, hardware encryption, Bluetooth, and all sorts of other additional bells and whistles.

The Modules

Vendors have consequently created a multitude of compact printed circuit board modules based around the ESP8266 chip. Some of these modules have specific identifiers, including monikers such as "ESP-WROOM-02" and and "ESP-01" through "ESP-14"; while other modules might be ill-labeled and merely referred to by a general description — e.g., "ESP8266 Wireless Transceiver." ESP8266-based modules have demonstrated themselves as a capable, low-cost, networkable foundation for facilitating end-point IoT developments. Espressif's official modules are presently ESP-WROOM-02 and ESP-WROOM-S2. The Ai-Thinker modules are succinctly labeled ESP-01 through ESP-14. (Note: many people refer to the Ai-Thinker modules with the unofficial monikers of "ESP8266-01" through "ESP8266-14" for clarity.) See the ESP8266 article on Wikipedia for more information about popular ESP8266 modules.

Espressif Systems



Wireless-Tag Technology

The Development Boards/Modules

ESP8266 based development boards/modules often incorporate a surface-mount PCB module, a on-board USB-to-serial bridge, and breakout to 0.1 inch pitch connections. For example, the NodeMCU Development Kits use Ai-Thinker modules, the Adafruit Feather HUZZAH uses an Ai-Thinker ESP-12S module with a SiLabs CP2104 USB-to-serial bridge chip, and the WEMOS D1 Mini version 2.3 uses an Ai-Thinker ESP-12S module with a WinChipHead CH340G USB-to-serial bridge chip. Other development boards don't use an intermediary module and instead directly incorporate the chip itself on-board — for example, WEMOS D1 Mini Pro uses ESP8266EX and WEMOS D1 Mini Lite uses ESP8285.

Where can I learn more about it?

Forums & Chat

Readings & Resources

Software Platforms, Firmwares & Frameworks

Where can I get it?

Disclaimer: Vendors are listed for informational purposes only. Buyers should use prudence and careful judgement when ordering. Before ordering, read all product descriptions and check vendor ratings when possible. Prices listed below are approximate and do not include shipping costs. Furthermore, prices listed below may be outdated, so be diligent and check for yourself.