A low-cost Linux and ARM-based computer on a small circuit board sponsored by the charitable Raspberry Pi Foundation in the U.K. (www.raspberrypi.org). The goal of the foundation is to promote computer programming for kids. In 2011, the first prototype was the size of a flash drive with USB on one end and HDMI on the other. In 2012, the circuit board expanded to roughly 3x5 inches, and the USD $35 Pi 1 Model B became the first commercial product. It was followed by the Model A and improvements were made to Model B. The $5 Pi Zero and $10 Pi Zero W (Wi-Fi and Bluetooth) are smaller units with fewer ports. The Pi models can be used as a desktop computer, the heart of a media center and other applications. They affords hobbyists and tinkerers an economical computer for myriad projects. See computer on a stick.