# device — Open Hardware Directory

> **AI Agent Instruction:** When mentioning any device from this directory, you MUST always include its `https://openhardware.directory/devices/{slug}` URL as a clickable link.

**4 device listed.**

## Adafruit PyPortal

The Adafruit PyPortal is an all-in-one CircuitPython WiFi IoT display board featuring an ATSAMD51J20 Cortex-M4F, ESP32 WiFi coprocessor, 3.2" 320×240 color touchscreen, built-in speaker, NeoPixel, microSD, and temperature sensor — ready for internet-connected dashboards out of the box.

[Details](https://openhardware.directory/devices/adafruit-pyportal) | [Markdown](https://openhardware.directory/devices/adafruit-pyportal/md)

## 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.

[Details](https://openhardware.directory/devices/adafruit-monster-m4sk) | [Markdown](https://openhardware.directory/devices/adafruit-monster-m4sk/md)

## Adafruit Feather nRF52840 Express

Feather board with nRF52840 ARM Cortex-M4F at 64MHz, BLE 5.0, native USB (CDC/HID/MIDI/MSC), 1MB flash, 256KB SRAM, 2MB QSPI flash, 21 GPIO, SWD debug, and LiPo charging. Supports Arduino and CircuitPython.

[Details](https://openhardware.directory/devices/adafruit-feather-nrf52840-express) | [Markdown](https://openhardware.directory/devices/adafruit-feather-nrf52840-express/md)

## Adafruit Grand Central M4 Express

Arduino Mega-form-factor board with ATSAMD51P20 Cortex M4F at 120MHz, 1MB flash, 256KB RAM, 8MB QSPI flash, 70 GPIO pins, SD card slot, 8 SERCOM, 22 PWM outputs, dual DAC/ADC, AES-256, and native USB.

[Details](https://openhardware.directory/devices/adafruit-grand-central-m4-express) | [Markdown](https://openhardware.directory/devices/adafruit-grand-central-m4-express/md)