During his Maker Faire Rome presentation, Arduino Co-Founder Massimo Banzi offered attendees a preview of the company’s new collaboration with Adafruit — the Arduino Gemma, a tiny wearable MCU board packed in a 1-inch (27mm) diameter package.
Similar to the original Adafruit Gemma, the mini yet powerful wearable platform board is powered by the versatile ATtiny85. The board will be default-supported in the Arduino IDE, equipped with an on/off switch and a microUSB connector. Since it is programmable with the Arduino IDE over USB, all Makers will have the ability to easily create wearable projects with all the advantages of being part of the Arduino family.
“We wanted to design a microcontroller board that was small enough to fit into any project, and low cost enough to use without hesitation,” Adafruit’s Limor Fried (aka LadyAda) explained in a blog post last September. “Gemma is perfect for when you don’t want to give up your Flora and aren’t willing to take apart the project you worked so hard to design. It’s our lowest-cost sewable controller.”
Ideal for small and simple projects sewn with conductive thread, the [tinyAVR based] Arduino Gemma fits the needs of nearly every entry-level wearable creations — ranging from reading sensors to driving addressable LED pixels.
To better visualize just how small we are talking, look at this image from an earlier version of the Adafruit Gemma.
“The ATtiny85 is a great processor because despite being so small, it has 8K of flash and 5 I/O pins, including analog inputs and PWM ‘analog’ outputs. It was designed with a USB bootloader so you can plug it into any computer and reprogram it over a USB port (it uses 2 of the 5 I/O pins, leaving you with 3),” Arduino noted in its announcement.
In addition to ATtiny85 MCU, other key hardware specs include:
- Operating Voltage: 3.3V
- Input Voltage (recommended): 4-16V via battery port
- Input Voltage (limits): 3-18V
- Digital I/O Pins: 3
- PWM Channels: 2
- Analog Input Channels: 1
- DC Current per I/O Pin: 40 mA
- DC Current for 3.3V Pin: 150 mA
- Flash Memory: 8 KB (ATtiny85) of which 2.5 KB used by bootloader
- SRAM: 0.5 KB (ATtiny85)
- EEPROM: 0.5 KB (ATtiny85)
- Clock Speed: 8 MHz
- MicroUSB for USB Bootloader
- JST 2-PH for external battery