Ahead of a maker class I’m teaching in a week or so I’ve been thinking of what kinds of things are appropriate, easy to understand but complete applications. One I came up with was a lightning calculator. Press one button when you see the lightning, press another button when you hear the thunder. The microbit takes the time difference between the two events and works out an estimate of how far away is the storm.
I’ve tried to represent what event the microbit expects by displaying either a lightning flash or a (poorly drawn) ear.