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5.0 (2 reviews)

$20.18 |
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5.0 (2 reviews)

The Adafruit GEMMA M0 is a tiny, coin-sized microcontroller board designed for wearable electronics and small projects. Despite its quarter-sized footprint, ...

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The Adafruit GEMMA M0 is a tiny, coin-sized microcontroller board designed for wearable electronics and small projects. Despite its quarter-sized footprint, it packs serious power with an ATSAMD21E18 32-bit Cortex M0+ processor, 256 KB of Flash, and 32 KB of RAM — a massive upgrade over the original ATtiny85-based Gemma.

The GEMMA M0 ships with CircuitPython pre-loaded. Plug it in, edit the main.py file with any text editor, and your project is ready — no IDE or compiler installation required. It also works with the Arduino IDE for those who prefer C/C++.

Key Features

  • ATSAMD21E18 32-bit Cortex M0+ – 48 MHz processor with 256 KB Flash and 32 KB RAM
  • Native USB – Works as a serial console, keyboard/mouse HID, or small disk drive on every OS
  • CircuitPython and Arduino Support – Program with Python or C/C++, no special software installation needed
  • Three Sew-Pads with Alligator-Clip Holes – Easy connections with conductive thread or clips for fast prototyping
  • 12-bit Analog Input – On each I/O pad, with internal pullups/pulldowns
  • True Analog Output – One pad supports 10-bit audio playback
  • Two High-Speed PWM Outputs – Drive servos, LEDs, and more
  • Hardware Capacitive Touch – All three pads work as touch sensors with no extra components
  • NeoPixel and DotStar Support – Drive 8,000+ pixels on any pin, with DMA-NeoPixel support on one pin for zero processor overhead
  • Hardware I²C and Serial – True hardware support on two pads (no bit-banging)
  • Built-in RGB DotStar LED – For status indication or visual feedback
  • On/Off Switch and Reset Button – Convenient power and restart controls
  • JST Battery Connector – For AAA or LiPo batteries (no built-in LiPo charging, safe for NiMH/alkalines)

Ideal For

  • Wearable electronics and e-textile projects
  • Small interactive LED installations
  • Beginner-friendly CircuitPython learning
  • Rapid prototyping with alligator clips
  • Portable, battery-powered projects

Package Contents

  • 1× Adafruit GEMMA M0 – Fully assembled and tested, with CircuitPython and example code pre-loaded
Note: The GEMMA M0 has the same pinout as the original Gemma, so existing Arduino code works without changes. USB cable not included.

Resources

Jargon buster

Plain-language definitions for the technical terms used above.

CircuitPython
A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
conductive thread
Thread made with metal or other conductive fibres so it can carry electricity while being sewn into fabric. It matters for wearable and textile projects because it can replace wire, but it has more resistance than normal hookup wire.
HID
Human Interface Device is a USB device class used for keyboards, mice, gamepads and similar controls. If a board supports HID over USB, it can act like an input device to a computer without needing a custom driver.
IDE
Short for Integrated Development Environment, a program used to write, run and manage code. It matters because some learners prefer a traditional coding workspace instead of a guided notebook-style lesson.
LED
A light-emitting diode is a small electronic component that lights up when current flows through it in the correct direction. In this kit, LEDs create the flashing effect, so polarity and correct soldering matter for the project to work.
LiPo
A lithium polymer rechargeable battery commonly used in portable electronics projects. It matters because LiPo batteries need correct charging circuitry and care, and this board includes hardware intended for that battery type.
microcontroller
A microcontroller is a small computer on a chip that runs your program and controls connected inputs and outputs. For this product, it is the part that reads buttons and sensors, drives the display and speaker, and communicates over Bluetooth.
native USB
Native USB means the microcontroller itself handles USB communication, rather than using a separate USB-to-serial chip. This matters for programming, debugging, and projects that need the board to act directly as a USB device.
NeoPixel
A type of addressable LED system where colour data is sent along a single digital data line from one LED or controller to the next. Compatibility matters because the timing and signal format must match for the lights or driver board to respond correctly.
PWM
Pulse Width Modulation is a way for a digital pin to simulate variable output power by switching on and off very quickly. It matters for controlling things like LED brightness, motor speed, or servo-style signals from a microcontroller pin.
RAM
RAM is temporary memory used while a device is running, and its contents are lost when power is removed. A “Run in RAM” mode is useful for testing settings without permanently programming the module, but it may not support every feature.
RGB
Short for red, green and blue, usually referring to an LED that can mix those three colours. It matters because controlling an RGB LED teaches how separate outputs combine to create different colours.
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