The MI:sound board is a speaker board for the BBC microbit. It features an on-board speaker, CR2032 battery holder, thumb wheel volume control and an easy access on/off switch. The MI:sound board can either be powered by the CR2032 battery (provided) or via the micro:bit USB or JST connections.
To use the MI:sound speaker board, the BBC micro:bit should be attached using the supplied bolts, spacers and nuts as shown to the right. Only Pin 0, 3V and GND need to be connected. Crocodile clips can also be used.
When assembled, the MI:sound board is connected directly to the 3V, GND and P0 connections on the micro:bit. The 3V and GND connections provide power to the micro:bit and the built in buzzer is connected to P0, which is the default output pin when using the audio functions in the MakeCode software. The board has an easy to access on/off switch, which makes it easy to turn a project on and off, rather than have to disconnect the power supply from the BBC micro:bit.
Like the MI:power board, MI:sound offers an elegant solution for micro:bit projects on the move. Both boards provide power to micro:bit, feature an on/off switch and allow you to output sound. Sound though, is a much bigger feature on the MI:sound board. Where the MI:power board features a buzzer, MI:sound has an actual speaker with a thumb wheel volume control. Not only is the speaker more versatile than a simple sounder, it is also much much louder. So, in brief; the MI:power board is more compact and MI:sound is better for projects where sound is an integral part of the project.