I came across the ESP8266, whilst editing a Stack Exchange question, What’s wrong with my ESP8266?
The ESP8266 module is a TTL “Serial to Wireless Internet” device. The ESP8266 module is a 3 V device, but it’s no wimp. It draws quite a bit of power. In fact, you’ll probably need to make sure that your circuit’s power supply can handle at least 1 amp of current.
Also, of interest is Suggestions for latest ESP8266 WiFi module and How to program ESP8266 with Arduino Uno pins 0 and 1?
See also Wee Serial WiFi for the ESP8266 in an XBee package.
This instructables link Using the ESP8266 module.
The SparkFun product page has some useful specifications listed:
Description: The ESP8266 WiFi Module is a self contained SOC with integrated TCP/IP protocol stack that can give any microcontroller access to your WiFi network. The ESP8266 is capable of either hosting an application or offloading all Wi-Fi networking functions from another application processor. Each ESP8266 module comes pre-programmed with an AT command set firmware, meaning, you can simply hook this up to your Arduino device and get about as much WiFi-ability as a WiFi Shield offers (and that’s just out of the box)! The ESP8266 module is an extremely cost effective board with a huge, and ever growing, community.
This module has a powerful enough on-board processing and storage capability that allows it to be integrated with the sensors and other application specific devices through its GPIOs with minimal development up-front and minimal loading during runtime. Its high degree of on-chip integration allows for minimal external circuitry, including the front-end module, is designed to occupy minimal PCB area. The ESP8266 supports APSD for VoIP applications and Bluetooth co-existance interfaces, it contains a self-calibrated RF allowing it to work under all operating conditions, and requires no external RF parts.
There is an almost limitless fountain of information available for the ESP8266, all of which has been provided by amazing community support. In the Documents section below you will find many resources to aid you in using the ESP8266, even instructions on how to transforming this module into an IoT (Internet of Things) solution!
Note: The ESP8266 Module is not capable of 5-3V logic shifting and will require an external Logic Level Converter. Please do not power it directly from your 5V dev board.
Note: This new version of the ESP8266 WiFi Module has increased the flash disk size from 512k to 1MB.
- 802.11 b/g/n
- Wi-Fi Direct (P2P), soft-AP
- Integrated TCP/IP protocol stack
- Integrated TR switch, balun, LNA, power amplifier and matching network
- Integrated PLLs, regulators, DCXO and power management units
- +19.5dBm output power in 802.11b mode
- Power down leakage current of <10uA
- 1MB Flash Memory
- Integrated low power 32-bit CPU could be used as application processor
- SDIO 1.1 / 2.0, SPI, UART
- STBC, 1×1 MIMO, 2×1 MIMO
- A-MPDU & A-MSDU aggregation & 0.4ms guard interval
- Wake up and transmit packets in < 2ms
- Standby power consumption of < 1.0mW (DTIM3)
There is also a most useful forum, Everything ESP8266.
I must give credit to the useful cover photo, which I took from How to use ESP8266 ESP-01 as a SENSOR web client.