This is an easy tutorial showing how you can control the brightness of an LED or adjust the speed of a DC fan using Arduino Board, a small BC547 transistor and a potentiometer. In my example the whole ...

When the microphone equipped Arduino detects enough noise, it will start a timer that keeps the fan running for two hours. If the tool keeps running, then more time gets added to the clock.

Maker and 3D printing expert James Bruton based in the United Kingdom has created a new Arduino project in the form of a unique type of craft thanks to its electric ducted fan (EDF) propulsion system.