Arduino open source single board computer boards arduino a000073 the arduino uno smd is a microcontroller board based on the atmega328 it 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 a ac to dc adaptor or battery to get star