The build seems straightforward on the surface. As the ruler is passed over a surface the device keeps track of exactly how far it has moved, making it an effective and very accurate ruler.

Until that day comes, we’ll just have to settle for steps beyond the wooden ruler — like the Kickstarter darling, the Rollova 2.0 Digital Ruler ($76.95, 13 percent off, from TNW Deals).

This is similar to how we need accurate rulers to measure lengths correctly. In the present case, a laser provides a sort of ruler, for measuring colours rather than distances, with an extremely ...

The ruler is actually a square multilayer silicon chip that is 25 mm on a side. Each is measured and certified by NIST for spacing and angles of the crystal planes of silicon atoms in the base ...