The micro:bit is a handheld, fully programmable microcontroller with a lot of built-in features.
A
25 red LED (light emitting diodes) that can flash shapes, numbers and messages. The LED form a 5 x 5 grid that can be set to turn on or off and the brightness can be controlled.
B
Buttons A & B are a form of input. They can detect when either of the buttons are being pressed and released.
C
An accelerometer on the micro:bit can detect changes in the micro:bit's speed by converting analogue information into digital form. The micro:bit can also detect a few standard actions e.g. shake, tilt and free-fall. A compass on the micro:bit detects magnetic fields such as the Earth's magnetic field. As such, it is possible to detect the direction it is facing or moving in degrees.
D
A low energy Bluetooth connection that can be used to interact with other Bluetooth enabled devices and the Internet.