Adafruit GEMMA - Miniature Wearable Electronic Platform

GEMMA is a tiny wearable platform board with a lot of might in a 1" diameter package. Powered by an Attiny85 and programmable with an Arduino IDE over USB, you'll be able to realise any wearable project! The Attiny85 is a fun processor because despite being so small, it has 8K of flash, and 5 I/O pins, including analog inputs and PWM 'analog' outputs. Adafruit have designed a USB bootloader so you can plug it into any computer and reprogram it over a USB port just like an Arduino (it uses 2 of the 5 I/O pins, leaving you with 3). In fact they even made some simple modifications to the Arduino IDE so that it works like a mini-Flora. Even though you can program GEMMA using the Arduino IDE, it's not a fully 100% Arduino-compatible board. There are some things you trade off for such a small and low cost microcontroller!

• GEMMA does not have a Serial port connection for debugging so the serial port monitor will not be able to send/receive data
• Some computers' USB v3 ports don't recognise the GEMMAs bootloader. Simply use a USB v2 port or a USB hub in between
• We do not have full Windows 8 driver compatibility tested. At this time we only have it working with Mac, Linux or Windows 7/XP

Here are some useful specifications!

• Super small, only 1.1" / 28mm diameter and 0.28" / 7mm thick.
• Easy-to-sew or solder pads for embedding in your wearable project
• Low cost enough, you can use one for every weekend project
• ATtiny85 on-board, 8K of flash, 512 byte of SRAM, 512 bytes of EEPROM
• Internal oscillator runs at 8MHz
• Ultra low power, draws only 9 mA while running
• USB bootloader with a nice LED indicator looks just like a USBtinyISP so you can program it with the Arduino IDE (with a few simple config modifications)
• Mini-USB jack for power and/or USB uploading, you can put it in a box or tape it up and use any USB cable for when you want to reprogram.
• We really worked hard on the bootloader process to make it rugged and foolproof
• ~5.25K bytes available for use (2.75K taken for the bootloader)
• On-board 3.3V or 5.0V power regulator with 150mA output capability and ultra-low dropout. Up to 16V input, reverse-polarity protection, thermal and current-limit protection.
• Power with either USB or external output (such as a battery) - it'll automatically switch over
• On-board green power LED and red pin #1 LED
• Reset button for entering the bootloader or restarting the program.
• 3 GPIO - The 3 independent IO pins have 1 analog input and 2 PWM output as well.
• Hardware I2C capability for breakout & sensor interfacing.

For more information about GEMMA, check out Adafruit's Learn guide. PRODUCT VIDEO