The native USB port of the NeoTrellis M4 can be used to turn the device into a MIDI USB component by using Arduino and tethering it to a computer or tablet. In standalone mode, as long as it is powered by a USB power plug, it will run whatever firmware is burned into it.
The NeoTrellis M4 features a 4x8 grid of elastomer button pads with a NeoPixel nestled in the center of each one. Read any/all button presses simultaneously thanks to the fully-diode'd matrix, and also set each button color to any of the 24-bit colors. The elastomer buttons are translucent and glow beautifully when lit.
The dual DAC of the SAMD51 offers two 12-bit, 500KSPS true analog outputs, connected to the left and right pins of a standard headphone jack. Since the DAC pins are also ADC pins, the left/right pins can also be used for audio line-level input.
To add more interactivity, a precision triple-axis accelerometer from Analog Devices, the ADXL343, is included as well and provides sensor information on tilt, motion, or tapping.
Finally, a 4-pin JST hacking port is available for extra add-ons. The JST port is STEMMA and Grove compatible and provides GND, 3.3V power, and two pins that can be used for I2C, ADC, or UART.