# Adafruit Monster M4SK

> The Adafruit Monster M4SK is a wearable dual-display Halloween mask board powered by ATSAMD51 Cortex-M4F at 120MHz with 8MB flash, two 240×240 IPS TFT eye displays, stereo audio, microphone, STEMMA connectors, and LiPo battery support for animated eye and mask projects.

## Quick Facts

- **Brand:** Adafruit
- **Board Type:** dev-board
- **Price:** ~$79.95
- **Product Readiness:** developer
- **CPU:** ATSAMD51J20 ARM Cortex-M4F @ 120MHz
- **CPU Architecture:** ARM Cortex-M4F
- **CPU Cores:** 1
- **RAM:** 256 KB
- **Flash:** 8 MB SPI flash
- **Power:** LiPo 3.7V battery (JST connector) or USB
- **Operating Voltage:** 3.3V

## Open Source

- **Status:** fully-open
- **Firmware:** Yes
- **Schematics:** Yes
- **PCB Layout:** Yes

## Compatible Firmware

circuitpython, arduino

## Use Cases

- wearable
- iot-display

## Components

- **ATSAMD51J20** (mcu): Microchip ATSAMD51J20 ARM Cortex-M4F at 120MHz with FPU, 256KB RAM, 1MB internal flash — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Fww1.microchip.com%2Fdownloads%2Fen%2FDeviceDoc%2FSAM-D5x-E5x-Family-Data-Sheet-DS60001507G.pdf&ref=openhardware.directory&product=adafruit-monster-m4sk&source=md-export)
- **INA219** (sensor): Power monitoring and battery management for LiPo charging and status — [Datasheet](https://openhardware.directory/r?to=https%3A%2F%2Flearn.adafruit.com%2Fadafruit-monster-m4sk%2Foverview&ref=openhardware.directory&product=adafruit-monster-m4sk&source=md-export)

## Protocols

- **I2C**: SDA: SDA, SCL: SCL
- **SPI**
- **UART**
- **ADC**
- **I2S**

## GPIO Map

| Pin | Name | Type | Functions |
|-----|------|------|-----------|
| D0 | D0 | — | GPIO, STEMMA Digital |
| D1 | D1 | — | GPIO, STEMMA Analog |
| SDA | SDA | — | I2C SDA, STEMMA QT |
| SCL | SCL | — | I2C SCL, STEMMA QT |

## Available Software

- **[CircuitPython]()** (open-source)
- **[Arduino]()** (open-source)

## Description

## Overview

The Adafruit Monster M4SK is a purpose-built wearable electronics platform designed for creating animated Halloween masks, costume props, and wearable art. At its core is the ATSAMD51 ARM Cortex-M4F processor running at 120MHz with 8MB of SPI flash for CircuitPython libraries and assets. The board drives two 240×240 pixel IPS TFT LCD displays independently — one for each eye — enabling smooth, realistic animated eye effects and custom graphics.

Audio capabilities include stereo line-out, a speaker output (with 8Ω 1W speaker), and a 4-wire microphone input for sound-reactive effects. Three STEMMA connectors provide easy access to digital, analog, and I2C expansion. Three selection buttons and a 9-wire extension cable (for separating the two eyes across a wider mask) complete the core feature set.

The Monster M4SK runs CircuitPython and comes with eye animation code built in. A JST connector supports 3.7V LiPo batteries (420mAh included), making it fully portable. It was originally sold as part of AdaBox 013. The board ships as the PCB assembly with connectors; the full kit also includes the LiPo battery, speaker, microphone assembly, plastic lenses, acrylic holders, elastic band hardware, and blank masks for decoration.

## Where to Buy

- [Adafruit](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F4281&ref=openhardware.directory&product=adafruit-monster-m4sk&source=md-export) — $79.95

## Resources

- [product](https://openhardware.directory/r?to=https%3A%2F%2Fwww.adafruit.com%2Fproduct%2F4281&ref=openhardware.directory&product=adafruit-monster-m4sk&source=md-export)
- [docs](https://openhardware.directory/r?to=https%3A%2F%2Flearn.adafruit.com%2Fadafruit-monster-m4sk%2Foverview&ref=openhardware.directory&product=adafruit-monster-m4sk&source=md-export)
- [github](https://openhardware.directory/r?to=https%3A%2F%2Fgithub.com%2Fadafruit%2FAdafruit_Learning_System_Guides&ref=openhardware.directory&product=adafruit-monster-m4sk&source=md-export)

## Tags

`adafruit`, `monster-m4sk`, `wearable`, `circuitpython`, `samd51`, `halloween`, `dual-display`, `animated-eyes`, `lipo`

## Images

![Adafruit Monster M4SK](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-monster-m4sk/908eabc20cd5.jpg)
![Adafruit Monster M4SK](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-monster-m4sk/9fc9d12955d4.jpg)
![Adafruit Monster M4SK](https://nbg1.your-objectstorage.com/openhardware-directory/entities/adafruit-monster-m4sk/5f87d69d09ba.jpg)

> **Battery Powered:** LiPo 3.7V 420mAh (included)

---
[View full device page](https://openhardware.directory/devices/adafruit-monster-m4sk)