Arduino is able to interpret signals from a variety of sensors. By placing a unit equipped with an ADXL345, an accelerometer for detecting motion, or a Piezo sensor on a door, it can notify you ...

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 Arduino ...