[Updated May 17] — Arduino.org announced a smaller, cheaper “Mini” version of the Arduino Yun SBC that offers fewer real-world ports, but gives more control to Linux.



In recent months, the Italian-based Arduino hacker project has been splitting into two rival factions. One of them — Arduino.srl, hosted at Arduino.org — has unveiled a new, smaller version of the Arduino Yun single board computer, called the Arduino Yun Mini, and also announced several upcoming boards.







Arduino Yun Mini (left) and original Arduino Yun (not exactly to scale)

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Arduino Srl showcased the new Yun Mini on May 15 at the Maker Faire Bay Area. This was the same event where Arduino two years ago announced its first Linux-ready board, the Arduino Yun. The Yun Mini sacrifices a number of interfaces in order to reduce size, and gives Linux more control over the board’s functions (see farther below). Like the original Arduino Yun and newly announced Arduino Yun Mini, one of Arduino.org’s other upcoming SBCs, the “Arduino Tian” (see farther below), runs the OpenWRT Linux based Linino distribution in addition to Arduino code.



An Arduino fork

In a May 15 blog post, Arduino Srl CEO Federico Musto gave his version of the Arduino schism, and related how he and Arduino co-founder Gianluca Martino, converted the manufacturing arm of Arduino, called Smart Projects Srl, into the Arduino-branded Arduino Srl entity. More background on the origins of the rift can be found on Hackaday in an interesting pair of posts here and here

In addition, Arduino Srl released an open source Arduino IDE-alpha development

system that is entirely based on JavaScript. The software will be available

for download on my.arduino.org by the end of the month, says the company.

The new IDE creates a problematic fork in the software, combined with the confusion of similar products being sold by both entities.

Arduino Srl also announced a new community web portal called my.arduino.org that plans to accept project designs from Arduino community makers. Arduino.org will then choose the best projects to invest in, and will sell the products on the site, as well as via its distribution network. The approach is somewhat similar to that of Quirky, which spun off Wink to sell the Wink automation hub.

On May 16, the original Arduino — Arduino LLC — announced on its Arduino.cc website that it has established a manufacturing partnership with Adafruit to make up for the departure of Smart Projects. The company, which is run by cofounder and spokesman Massimo Banzi, has listings for the original Yun, but not the new Yun Mini model. Like Arduino.org (Arduino Srl), Arduino.cc (Arduino LLC) appears to list all the other Arduino boards, including the new Zero model.



Arduino TRE

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Arduino.cc also lists as “coming soon” the Linux-ready Arduino TRE SBC, which is not currently shown on Arduino.org. The slow-to-arrive TRE, which was announced in Oct. 2013 and entered its second beta testing round in December, runs a more feature-rich Linux distribution on an ARM Cortex-A8 TI Sitara SoC. Interestingly, Arduino LLC, which teamed up with Intel on the Galileo board that also runs a full Linux distro rather than Linino, is said to be collaborating with BeagleBoard.org on the development of the TRE.



Yun Mini details

Like the original Arduino Yun, which now sells for $76 at Mouser, the $60 Arduino Yun Mini runs the OpenWRT based Linino on Qualcomm’s MIPS24k-based Atheros AR9331 SoC clocked to 400MHz. Like its predecessor, the new model also offers an Atmel ATmega32U4 chip running Arduino code, and ships with a 16MHz crystal oscillator, 64MB of DDR2 RAM, and 16MB of flash, 6MB of which is used by Linino.







Arduino Yun Mini topside detail

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Arduino Yun Mini rear detail

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The Mini is considerably smaller than the 73 x 53mm original in one dimension, measuring 71.1 x 22.9mm, and it’s half the weight, at 16 grams. The smaller footprint was partially enabled by removing the earlier Ethernet port, USB host port, and microSD slot. This makes it more comparable to the COM-like designs adopted by many OpenWRT-on-AR9331 SBCs such as the Weio The Yun Mini is expandable, however, with optional “dog” accessories. The dogRJ45 adds a 10/100Mbps Ethernet port with an 802.3 switch. The dogUSB port incorporates a USB type A connector along with a USB 2.0 hub. Finally, the dog eMMC add-on makes up for the missing microSD slot with 4GB of eMMC flash, plus a USB type A port.

Like the original, the Yun Mini also offers built-in 802.11n WiFi. It provides 20 GPIO pins, up from 14 on the original. Up to seven of the pins can be used for PWM outputs, and up to 12 for analog inputs.







Arduino Yun Mini data exchange between Arduino-based ATmega32U4 and Linino-driven Atheros AR9331 processors

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The sole remaining real-world port is the micro-USB port, which is typically used for 5VDC power. As an alternative, you can choose to use a “Vin” pin, which requires a regulated 5VDC power supply. The Mini Yun also provides three reset buttons.

On the original Yun, the Linino code was pretty much limited to networking duties, acting as a slave to the Arduino code running on the ATmega32U4 chip. With the Yun Mini, however, “it is possible to access the I/O pins of the Atheros AR9331 together with the I/O pins of the AVR 32u4,” says Arduino. Each of the AR9331 pins can now be used by Linino as peripherals of the Linux Kernel, says the company.

Like the Arduino Leonardo board, with which both Yun boards claim compatibility, the Arduino Yun Mini provides the ATmega32u4 with built-in USB communication, “eliminating the need for a secondary processor,” says Arduino. This is said to enable the board to appear to a USB-connected computer as a mouse and keyboard, “in addition to a virtual (CDC) serial / COM port,” says the company.







Arduino Yun Mini angled view, and pin assignments

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Arduino TIAN and more, previewed

At the Maker Faire, Arduino is also previewing three upcoming Arduino boards: the Arduino TIAN, Arduino M0, and Arduino M0 Pro. Of these, the TIAN pairs a Linino-enabled 560MHz MIPS 9432 processor for high level functions and networking, along with a SAMD21 32-bit Cortex M0+ microprocessor for real-time control, with the two processors communicationg at high speed over USB 2.0.









Arduino TIAN front/back (above) and block diagram

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The M0 and M0 Pro, on the other hand are “traditional” Arduino SBCs, without onboard Linino processors.

There was no word on the availability of the Linux-ready Arduino TRE SBC, which was announced in Oct. 2013. The TRE runs a more feature-rich Linux distribution on an ARM Cortex-A8 TI Sitara SoC. The TRE development board entered its second beta testing round in December.



Further information

The Arduino Yun Mini appears to be available now for $59.90 at Digi-Key. More information may be found at Arduino.org’s Arduino Yun Mini product page. The Arduino TIAN, meanwhile is expected to ship in September.

