# 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.

**10 device listed.**

## Adafruit HalloWing M4 Express

Skull-shaped ATSAMD51J19 dev board (120MHz Cortex-M4F) with a 1.54" 240×240 IPS TFT, 4 capacitive touch inputs, 4 NeoPixels, accelerometer, speaker driver, and LiPoly charging. Perfect for Halloween props and wearables.

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

## Adafruit Feather STM32F405 Express

High-speed Feather-form-factor dev board with STM32F405 ARM Cortex-M4F @ 168MHz, 1MB Flash, 192KB RAM, 2MB SPI Flash, USB-C, STEMMA QT, SD card socket, and LiPo charging. Adafruit's fastest CircuitPython board.

[Details](https://openhardware.directory/devices/adafruit-feather-stm32f405-express) | [Markdown](https://openhardware.directory/devices/adafruit-feather-stm32f405-express/md)

## Adafruit ItsyBitsy nRF52840 Express

Tiny breadboard-friendly Bluetooth LE board with Nordic nRF52840 Cortex-M4F @ 64MHz, 1MB Flash, 256KB RAM, 2MB QSPI Flash, 21 GPIO, and native USB — all in a 36×17.6mm footprint. Supports CircuitPython and Arduino.

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

## Adafruit Feather nRF52840 Sense

Sensor-rich BLE Feather with Nordic nRF52840 (64MHz Cortex-M4F), 6 onboard sensors (9-DoF IMU, magnetometer, proximity/light, PDM mic, humidity, barometric pressure), 21 GPIO, and FCC/IC/TELEC certified.

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

## PJRC Teensy 4.1

High-performance microcontroller with NXP i.MX RT1062 ARM Cortex-M7 @ 600MHz, 1MB RAM, 2MB Flash, 100Mbps Ethernet PHY, SD card, 55 GPIO, dual 480Mbps USB, and 3 CAN Bus. Expanded Teensy 4.0 sibling.

[Details](https://openhardware.directory/devices/pjrc-teensy-4-1) | [Markdown](https://openhardware.directory/devices/pjrc-teensy-4-1/md)

## Adafruit Feather M4 CAN Express

CAN-bus-capable Feather with ATSAME51J19 ARM Cortex-M4F @ 120MHz, built-in CAN transceiver + 5V booster, USB-C, 21 GPIO, 2MB SPI Flash, dual DAC, and LiPo charging. Ideal for automotive and industrial CAN Bus projects.

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

## Arduino MKR WiFi 1010

Compact IoT Arduino with SAMD21 Cortex-M0+ @ 48MHz, u-blox NINA-W102 WiFi + Bluetooth module, ATECC508 crypto chip, 256KB Flash, 32KB SRAM, USB full-speed, LiPo charging, and MKR shield compatibility.

[Details](https://openhardware.directory/devices/arduino-mkr-wifi-1010) | [Markdown](https://openhardware.directory/devices/arduino-mkr-wifi-1010/md)

## Arduino Uno R3

The quintessential beginner microcontroller board with ATmega328P @ 16MHz, 32KB Flash, 2KB SRAM, 14 digital I/O, 6 analog inputs, USB-B for programming, DC barrel jack, and the R3 expanded shield header. Open-source hardware.

[Details](https://openhardware.directory/devices/arduino-uno-r3) | [Markdown](https://openhardware.directory/devices/arduino-uno-r3/md)

## Adafruit Feather RP2040

Feather-form-factor board with Raspberry Pi RP2040 dual-core Cortex-M0+ @ 133MHz, 264KB SRAM, 8MB Flash, 21 GPIO, 4 ADC, 2 PIO peripherals, USB-C with UF2 bootloader, STEMMA QT, and LiPo charging. Runs CircuitPython and MicroPython.

[Details](https://openhardware.directory/devices/adafruit-feather-rp2040) | [Markdown](https://openhardware.directory/devices/adafruit-feather-rp2040/md)

## Adafruit ItsyBitsy RP2040

Tiny 36×18mm breadboard-friendly board with Raspberry Pi RP2040 dual-core Cortex-M0+ @ 133MHz, 264KB SRAM, 8MB Flash, 23 GPIO, 4 ADC, 2 PIO peripherals, and Micro-USB. Runs CircuitPython and MicroPython.

[Details](https://openhardware.directory/devices/adafruit-itsybitsy-rp2040) | [Markdown](https://openhardware.directory/devices/adafruit-itsybitsy-rp2040/md)