Graham Prophet
EDN Europe
Distributor RS Components has the Arduino Yun Mini, which it positions as an affordable, small and lightweight Linux-based Wi-Fi prototyping solution
Aimed at embedded engineers, hackers and students, the Arduino Yun Mini is a redesign of the Arduino Yun Wi-Fi microcontroller board and has been re-engineered to be used with a breadboard, making prototyping easier, and also provides its functionality in a light and highly compact package.
The Yun Mini has approximate PCB dimensions of 71.1 × 22.9 mm, which is less than half the area of the Arduino Yun PCB, which has dimensions of approximately 68.6 × 53.3 mm with its USB connector extending the length to approximately 73 mm. In addition, the weight of the Yun Mini at 16 g is half that of the Yun. The board’s small size suits it for use in small spaces and especially projects for home automation, where locating smaller devices in small boxes can improve siting flexibility.
The Yun Mini offers an affordable breadboard PCB with an ATmega32U4 microcontroller and the Qualcomm Atheros AR9331 system-on-chip IC with a MIPS 24K CPU, which operates at up to 400 MHz and supports a Linux distribution based on OpenWRT called Linino. A bridge library enables communication between the two processors, providing Arduino programs the ability to run shell scripts, communicate with network interfaces and receive information from the AR9331 processor.
The board has built-in Wi-Fi (IEEE 802.11b/g/n operation up to 150 Mbps) and supports 20 digital input/output pins, seven of which can be used as PWM outputs and 12 as analogue inputs. Other specifications include a 16 MHz crystal oscillator, a micro-USB connector, an ICSP header, two reset buttons and one user button.
The Yun Mini is similar to the Arduino Leonardo in that the ATmega32u4 has built-in USB communication, eliminating the need for a secondary processor, which allows the Yun Mini to appear to a connected computer as a mouse and keyboard, as well as a virtual (CDC) serial/COM port.
The Yun Mini can be customised from a choice of up to two out of three available accessories, which are the dogRJ45, the dogUSB and the dogUSB eMMC. The dogRJ45 is a 10/100 Mbps Ethernet port; the dogUSB is a USB A type connector with USB 2.0 hub that features a slot for a mini SD to extend the memory of the board; and the dogUSB eMMC is a USB port type A with an integrated 4 GB of Flash.
The board can be powered via the micro-USB connection with 5 VDC, which is the recommended option. However, a regulated 5 VDC can also be used to power the board via the Vin pin. The Yun Mini can be programmed with Arduino software downloaded from arduino.org/downloads http://arduino.org/downloads or the Linino IO from http://www.linino.org.
