Olympia Circuits Teases Arduino Programmers With $60 Arno Shield by Ray Willington — Monday, April 29, 2013, 05:50 PM EDT Comments ...

You also need to select the transistor by the type of fan that you use. In my case I used the well-known BD139 transistor and a 9V battery to provide power to the fan and transistor. The LM35 ...