A potentiometer is a simple knob that provides a variable resistance. In this project, potentiometer values are read in through an 'Analog In' pin. The values are then used to control the blinking rate of an LED.
Use a 1kΩ potentiometer. Connect three wires to the Arduino board. The first goes to ground from one of the outer pins of the potentiometer. The second goes from 5 volts to the other outer pin of the potentiometer. The third goes from analog input 2 to the middle pin of the potentiometer.