Pinhead mirror

[Image:Pinhead Camera.png|thumb|right|Principle of a pinhead camera. Light rays from the object reflect off a small mirror and are projected as an image.]
A pinhead mirror can be used to create a camera similar to a pinhole camera. Instead of passing through a tiny aperature, the light to form the image is reflected by a small disc-shaped mirror. One advantage is that a pinhead mirror can be swiveled to scan a scene or project a scene to different locations.
Pinhead mirror technology was protected under US patent 4,948,211 - "Method and Apparatus for Optical Imaging Using a Small, Flat Reflecting Surface" until the patent expired in 2009.
Disco balls can be used as pinhead mirrors to project solar images. The math behind them is the same as for a square pinhole.