Arduino Yun

The Arduino Yún is a microcontroller board based on the ATmega32u4 and the Atheros AR9331. The Atheros processor supports a Linux distribution based on OpenWRT named Linino. The board has built-in Ethernet and WiFi support, a USB-A port, micro-SD card slot, 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, an ICSP header, and a 3 reset buttons. 
The Yún distinguishes itself from other Arduino boards in that it can communicate with the Linux distribution onboard, offering a powerful networked computer with the ease of Arduino. In addition to Linux commands like cURL, you can write your own shell and python scripts for robust interactions.
The Yún is similar to the Leonardo in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Yún to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.

Note:
There is no on-board regulator for voltages greater than 5VDC
It is recommended to power the board via the micro-USB connection with 5VDC
If you are powering the board though the Vin pin, you must supply a regulated 5VDC

AVR Arduino microcontroller Specifications:

•  
• ATmega32u4 Microcontroller    
• 5V Operating Voltage    
• 5V Input Voltage    
• 20 Digital I/O Pins    
• 7 PWM Channels    
• 12 Analog Input Channels    
• 40 mA DC Current per I/O Pin    
• 50 mA DC Current for 3.3V Pin    
• 32 KB Flash Memory (of which 4 KB used by bootloader)
• 2.5 KB SRAM    
• 1 KB EEPROM    
• 16 MHz Clock Speed

Linux microprocessor Specification:

• Atheros AR9331 Processor  
• MIPS @400MHz Architecture   
• 3.3V Operating Voltage   
• 10/100Mbit/s Ethernet IEEE 802.3
• IEEE 802.11b/g/n WiFi   
• 2.0 Host/Device USB Type-A   
• Micro-SD Card Reader only
• 64 MB DDR2 RAM   
• Flash Memory 16 MB
• PoE compatible 802.3af card support