Resistors are color coded to indicate their resistive value. If you already know how to read the color code—or once you learn how—you’ll be able to glance at a resistor and tell automatically what its value is. But what about other components in your projects? What about the LEDs, potentiometers, buzzers, or even the wires themselves? How much resistance do they add to the circuit? To find the answer, you’ll need an ohmmeter, a device that measures the resistance of an electrical component. With a resistor, a breadboard, and a few wires, you can turn your Arduino into this useful, awesome measuring device. The Arduino Ohmmeter is shown in Figure 13-1.