This solar tracker system uses the Arduino UNO board, a servomotor, 2 LDRs and 2 resistors to rotate the solar panel towards the Sun or a source of light. Here https ...

An Arduino can be used to test the life of any battery with less than 5 volts, Boxall says. So, for a quick way to see how much juice your AAA, AA, C, or D batteries have left, build this ...