The BBC micro:bit has a number of built-in sensors that make it really easy to get started with a few simple projects. 

In this lesson you will learn how to use the micro:bit's accelerometer to make a simple movement activated alarm. You will also learn how to use the micro:bit's magnetometer chip to detect the presence of a magnet.

If you flip your micro:bit over, you can see both the accelerometer and magnetometer (compass) marked on the bottom left of the photograph above.