Adafruit GEMMA v2 Miniature Wearable Electronic Platform

Deprecation Warning: The Gemma bit-bang USB technique it uses doesn't work as well as it did in 2014, and many modern computers won't work well. While we still carry the Gemma for maintaining older projects, we no longer recommend it. Please check out the Gemma M0 which has built-in USB, more capabilities, and is comparable in price!

Love FLORA but want a bite-sized version? The Adafruit GEMMA v2 is a tiny wearable platform board with lots of power packed in a 1" diameter package. Powered by an ATtiny85 and programmable via the Arduino IDE over USB, it’s ideal for wearable projects.

This ultra-small microcontroller board is low-cost and perfect for embedding into any wearable project. It features a USB bootloader for easy programming, sewable/solderable pads, and runs an 8MHz internal oscillator.

• Small size: 1.1" / 28mm diameter, 0.28" / 7mm thick
• Easy to sew or solder onto wearable electronics
• Uses ATtiny85 microcontroller: 8K flash, 512 bytes SRAM, 512 bytes EEPROM
• Low power consumption - draws only 9 mA while running
• USB bootloader with LED indicator
• Micro-USB connector for power and programming
• On-board 3.3V regulator with 150mA output and protections
• Can be powered by USB or external battery; auto-switching power input
• Green power LED and red status LED on pin #1
• Reset button to enter bootloader or restart program
• 3 GPIO pins: 1 analog input and 2 PWM outputs
• Hardware I2C for sensor & breakout interfacing

Note: GEMMA's Arduino IDE usage requires simple config modifications and is not fully compatible with all Arduino features, and some USB v3 ports may not recognize it properly. Using USB v2 ports or hubs is recommended.

For more details and tutorials, please visit the GEMMA Learn Guide.