Introducing the Arduino GEMMA

This wearable board is one bad mamma GEMMA!

First announced last fall during Maker Faire Rome, the Arduino GEMMA is now available. The board, which was developed in collaboration with Adafruit, is a tiny wearable MCU that packs a whole lot of awesomeness in a 1.1” (28mm) diameter.


Similar to the latest version of the Adafruit GEMMA, the mini yet powerful platform is based on the ATtiny85. The MCU is supported in Arduino IDE (1.6.4 or higher) and programmable via microUSB. This enables all Makers to easily create wearable projects with all the advantages of being part of the Arduino family.

“It’s perfect for when you don’t want to give up your Adafruit FLORA and you aren’t willing to take apart the project you worked so hard to design. It’s the Adafruit and Arduino lowest-cost sewable controller,” Adafruit notes.


Ideal for small and simple projects sewn with conductive thread like the LilyPad Arduino, the tinyAVR powered Arduino GEMMA fits the needs of nearly every entry-level wearable creation — ranging from reading sensors and driving addressable LED pixels to Apple Watch-inspired buzzing mindfulness bracelets. The board features a USB bootloader with a nice LED indicator that resembles a USBtinyISP, allowing Makers to program it with the Arduino IDE (with just a few modifications). Beyond that, the Arduino GEMMA is equipped with a mini-USB jack for power and/or USB uploading.


“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. We 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),” Adafruit adds. “In fact, we even made some simple modifications to the Arduino IDE so that it works like a mini-Flora.”


Keep in mind that although it can be configured using the Arduino IDE, it is not entirely Arduino-compatible. Aside from the on-board tinyAVR MCU, other key specs include:

  • Size: 1.1” (28mm) diameter and 0.28″ (7mm) thick
  • Operating Voltage: 3.3V
  • Input Voltage: Up to 16V (reverse-polarity protection, thermal and current-limit protection)
  • I/O Pins: 5 (of which 2 can be used as PWM outputs and 1 as analog input)
  • Flash Memory: 8KB (ATtiny85)
  • SRAM: 512B (ATtiny85)
  • EEPROM: 512B (ATtiny85)
  • Clock Speed: 8MHz
  • MicroUSB for USB bootloader
  • JST 2-PH for 3.7 external Li-Ion battery
  • Hardware I2C capability for breakout/sensor interfacing

Think you may like an Arduino Gemma for your next DIY wearable project? The board is now available for $9.95 on both and Adafruit’s online store.

1 thought on “Introducing the Arduino GEMMA

  1. Pingback: Adafruit notes that the Arduino GEMMA is coming soon - Internet of Things | Wearables | Smart Home | M2M

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