Arduino open source single board computer boards arduino a000066 the arduino uno board a000066 r3 is a microcontroller board based on the atmega328it has 14 digital inputoutput pins of which 6 can be used as pwm outputs 6 analog inputs a 16 mhz crystal oscillator a usb connection a power jack an icsp header and a reset button it contains everything needed to support the microcontroller simply connect it to a computer with a usb cable or power it with an ac to dc adaptor or batter