Arduino Yun Mini tempts embedded engineers and students

13th July 2015

Mick Elliott

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The new Arduino Yun Mini extends the Arduino portfolio of open-source electronics development and prototyping boards of RS Components (RS). Aimed at embedded engineers, hackers and students, the Arduino Yun Mini is a redesign of the Arduino Yun WiFi 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 71.1mm x 22.9mm, which is less than half the area of the Arduino Yun PCB, which has dimensions of approximately 68.6mm x 53.3mm with its USB connector extending the length to approximately 73mm.

In addition, the weight of the Yun Mini at 16g is half that of the Yun. The board’s small size makes it ideal 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 400MHz 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 WiFi (IEEE 802.11b/g/n operation up to 150Mbps) 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 16MHz 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 board 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 10/100Mbps 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 4GB of Flash.

The board can be powered via the micro-USB connection with 5V DC, which is the recommended option. However, a regulated 5V DC can also be used to power the board via the Vin pin.