An often neglected feature of the Raspberry Pi is that it actually has two types of video output. The high quality, high resolution HDMI output and the yellow RCA jack that outputs composite video at a much lower quality. Miniature displays are readily available for this composite format, and are often used for things like CCTV security and pocket TVs.
In this tutorial, you will learn how to attach a miniature display to your Raspberry Pi and to adjust the Pi's settings to reduce the resolution sufficiently to read the screen.
