WiFi and the Raspberry Pi
Connecting to the Raspberry Pi
The FTDI to USB cable is the easiest way to provide power and communicate with the ESP8266 Huzzah board. You can also hook up power separately (3.3V or 5V battery) and use the serial pins to connect to a Raspberry Pi. Next, I'll talk about the software options available and show an example of each.
The Three Main Firmware Options
AT commands go way back. The AT command set is a specific command language originally developed by Dennis Hayes for the Hayes Smartmodem (300 baud) in 1981. The command set consists of a series of short text strings that combine to control complex behavior. The vast majority of dial-up modems used this command set or similar extensions.
Forward to 2015. A version of the AT command set is used by the ESP8266 to control the WiFi functions on the chip. This is only one of three major options for firmware, and as you will see, the least reliable at this time. Two equally useful references to the AT command set used by the ESP8266 can be found online [3] [4].
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