The Yún has two processors on board. One is an ATmega32U4 like on the Leonardo. The other is an Atheros 9331, running Linux and the OpenWRT wireless stack, which enables the board to connect to WiFi and Ethernet networks. It is possible to call programs or custom scripts on the Linux system through the Arduino to connect with various internet services. The Yún Shield shares the same architecture and features, but it is a shield and needs to be attached to a board, where the microcontroller is interfaced with the Atheros processor through hardware Serial port.

The Bridge library simplifies communication between the ATmega32U4 - or the board attached if you use the shield - and the AR9331. Bridge commands from the board microcontroller are interpreted by Python on the AR9331. Its role is to execute programs on the GNU/Linux side when asked by Arduino, provide a shared storage space for sharing data like sensor readings between the Arduino and the Internet, and receiving commands from the Internet and passing them directly to the Arduino.

Bridge allows communication in both directions, acting as an interface to the the Linux command line. For a brief explanations of the terminal and executing commands on Linux see here.

To become familiar with the Yún family boards please see the Yún getting started page and the or the Yún Shield getting started page.

Process

Process is used to launch processes on the Linux processor, and other things like shell scripts.

Console

Console can be used to communicate with the network monitor in the Arduino IDE, through a shell. Functionally, it is very similar to Serial.

FileIO

An interface to the Linux file system. Can be used to read/write files on the SD card, or on the USB memory if you are using the Yún Shield.

HttpClient

Creates a HTTP client on Linux. Acts as a wrapper for common CURL commands, by extending Process.

Mailbox

An asynchronous, session-less interface for communicating between Linux and Arduino.

BridgeClient

An Arduino based HTTP client, modeled after the EthernetClient class.

BridgeServer

An Arduino based HTTP server, modeled after the EthernetServer class.

Temboo

An interface to Temboo making it easy to connect to a large variety of online tools. See the Tembo documentation for more.

Examples

• Bridge: Access the pins of the board with a web browser.
• Console ASCII Table: Demonstrates printing various formats to the Console.
• Console Pixel: Control an LED through the Console.
• Console Read: Parse information from the Console and repeat it back.
• Datalogger: Store sensor information on a SD card.
• File Write Script: Demonstrates how to write and execute a shell script with Process.
• HTTP Client: Create a simple client that downloads a webpage and prints it to the serial monitor.
• HTTP Client Console: Create a simple client that downloads a webpage and prints it to the serial monitor via WiFi using Console.
• Mailbox Read Messages: Send text messages to the Arduino processor using REST API through a browser.
• Process: Demonstrates how to use Process to run Linux commands.
• Remote Due Blink: Demonstrates how to upload remotely a sketch on DUE boards.
• Shell Commands: Use Process to run shell commands.
• SpacebrewYun: See the Spacebrew documentation pages for more infos on the Examples listed in the Arduino Software.
• Temboo: See the Temboo documentation section for more infos on the Examples listed in the Arduino Software.
• Temperature Web Panel: Post sensor data on a webpage when requested by a browser.
• Time Check: Get the time from a network time server and print it to the serial monitor.
• WiFi Status: Runs a pre-configured script that reports back the strength of the current WiFi network.
• Yun First Config: Connect your Yun product to the WiFi networks in a breeze using the Serial Monitor and answering a few simple questions within it.
• Yun Serial Terminal: Access the Linux Terminal through the serial monitor.

Bridge Class

• Bridge Constructor

Functions

• begin()
• put()
• get()
• transfer()

Process Class

• Process Constructor

Functions

• begin()
• addParameter()
• run()
• runAsynchronously()
• running()
• exitValue()
• close()
• runShellCommand()
• runShellCommandAsynchronously()
• available()
• read()
• write()
• peek()
• flush()

Console Class

• Console Constructor

Functions

• begin()
• end()
• buffer()
• noBuffer()
• connected()
• available()
• read()
• write()
• peek()
• flush()

FileIO Class

• FileIO

Functions

• FileSystem.begin()
• FileSystem.open()
• FileSystem.exists()
• FileSystem.mkdir()
• FileSystem.rmdir()
• FileSystem.remove()

• File

• close()
• rewindDirectory()
• openNextFile()
• seek()
• position()
• size()
• available()
• read()
• write()
• peek()
• flush()

Mailbox Class

• Mailbox

Functions

• begin()
• end()
• readMessage()
• writeMessage()
• writeJSON()
• messageAvailable()

HttpClient Class

• HttpClient

Functions

• get()
• getAsynchronously()
• ready()
• getResult()

BridgeClient Class

• BridgeClient
  
• BridgeSSLClient

Functions

• stop()
• connect()
• connected()
• available()
• read()
• write()
• peek()
• flush()

BridgeServer Class

• BridgeServer

Functions

• begin()
• listenOnLocalhost()
• noListenOnLocalhost()
• write()

Deprecated classes

YunClient Class

• YunClient

YunServer Class

• YunServer