AREF GND RESET 3V3 PWM PWM PWM L TX RX USB EXT PWR SEL PWR ICSP PWM PWM PWM TX RX 3 1 2 1 1 1 0 1 9 8 DIGITAL 7 6 5 4 3 2 1 0 1 5V Gnd POWER www.arduino.cc ANALOG IN Vin 0 1 2 3 4 5 Arduino