What is an Arduino board?

The Arduino Uno, the most well-known Arduino board, is a microcontroller board based on the ATmega328 datasheet (http://www.atmel.com/dyn/resources/prod_documents/doc8161.pdf), which is the brains of the board. It is about 3 x 2 inches in size. It has 14 digital input/output pins, 6 analog input pins, and 32 kilobytes of flash memory.

Each board contains a reset button. In addition, it includes a USB port so that, when it is connected to a computer, it becomes a source of power as well as a communication tool. If you are not connected to a computer, you can use an alternate power source such as an AC 9-to-12 V DC adapters that can be connected by plugging a 2.1 mm center-positive plug into the board's power jack, or a 9 V battery pack.

The six digital pins with tilde symbol next to the number are the pins that allow for Pulse Width Modulation (PWM), which is a technique for controlling power and simulating an analog signal on a digital input pin. One reason for...