Adafruit GEMMA M0 - Miniature wearable electronic platform

The Adafruit Gemma M0 is a super compact and powerful microcontroller board that fits into the palm of your hand, measuring just about the size of a quarter. Designed for wearables and small projects, it combines a small form factor with impressive performance. While it may look cute with its round shape and friendly alligator-clip sew pads, the Gemma M0 is built to handle serious tasks.

This upgraded version of the classic ATtiny85-based Gemma replaces the old 8-bit microcontroller with the mighty ATSAMD21E18, a 32-bit Cortex M0+ processor. It delivers a significant performance boost, including 256KB of flash memory (8 times more than the ATtiny85), 32KB of RAM (64 times more), and a 48MHz clock speed (6 times faster). This makes the Gemma M0 perfect for more complex wearable projects and applications.

One of the standout features of the Gemma M0 is its ease of use. It comes pre-loaded with CircuitPython, so when you plug it in, it appears as a small disk drive with a "main.py" file. You can edit this file with any text editor to start building your project with Python—no IDE or complicated setup required. This makes it incredibly convenient, as you can use it on any computer, even a Chromebook or one without software installation options.

Key features and upgrades include:

• Same size and pinout as the classic Gemma, making it easy to switch from older versions
• Native USB support for USB serial communication, keyboard/mouse HID, and even as a disk drive for storing Python scripts
• Full compatibility with both the Arduino IDE and CircuitPython
• Built-in RGB DotStar LED for customizable lighting effects
• Three large sew-pads for conductive thread or alligator clips, perfect for quick prototyping
• True analog output on one pad for 10-bit audio quality and two high-speed PWM outputs for driving servos, LEDs, etc.
• Capacitive touch sensors on all three I/O pads (no extra components needed)
• NeoPixel and DotStar support with enough memory to control over 8000 pixels
• Hardware I2C and Serial communication for connecting to various devices
• Onboard reset switch and built-in on/off switch
• JST battery connector for AAA or LiPoly batteries (note: no built-in charging for LiPoly, so it’s safe for NiMH/alkaline batteries)

Each Gemma M0 comes fully assembled, with CircuitPython and example code already programmed, so you can get started right away. Whether you’re building a wearable or small electronic project, the Gemma M0 makes it easy, fast, and fun.

Technical Details:

• Dimensions: 27.95mm (1.1") round x 6.4mm (0.25") high
• Weight: 2.1g

Revision History:

• July 7, 2023: New version includes improved tactile buttons, though both versions are functionally identical except for this update.