History of Digital Calipers

Modern technology is quickly revolutionizing how researchers and illustrators in the natural sciences go about their work. Much of this results from the development of new methods for the scanning, digitizing, and measurement of objects.
Among the most popular of these devices are electronic calipers that combine the ease of use and higher accuracy of digital calipers with a direct connection to the personal computer, generally through the serial (RS-232) or Universal Serial Bus (USB) port in the back. Digital calipers provide accuracy of 0.001 mm or better. Electronic calipers then took this a step further by providing not only the digital display but also in allowing the information to be sent directly to the calipers. The whole system can be run by small batteries. This makes electronic calipers transportable and their use flexible while they retain very high levels of accuracy and repeatability. Current programs allow the data to be sent directly to destination programs such as spreadsheets or database.
If many measurements will be referred to repeatedly, electronic caliper systems provide a useful way to take and store data more quickly and accurately than with digital calipers alone. If caliper use is infrequent, digital calipers may be the most efficient option.
Digitizing is the process of translating an analog world into the digital from recognized by computers. There are two major approaches: point digitizing and scanning. Both are used extensively for natural science research and , consequently, should be useful for illustrators.
Point digitizing occurs whenever the two-or-three-dimensional coordinates of selected points are taken one-by-one and stored. These can be individual points that are part of lines or surface. The accuracy of two-dimensional digitizers typically is 1000 lines per inch or better. Most digitizers work by having two groups of densely packed wires, one at right angles to the other, under a plastic or glass cover—the digitizing surface. A stylus (pen-like device) or cursor (puck-like structure with cross hairs) is used to digitizing the points of interest. The digitizing pad determines which sire of each of the two sets is closest to the position of the point of the stylus or cross hairs of the cursor. These two wire reflect the x- and y-coordinates of that position. Buttons on the stylus (typically one or two) or cursor (3, 4, 12 or more) allow the user to select different options while digitizing. A stylus is very useful for sketching , drawing, and digitizing single or smaller numbers of points at any one time and tend to be much more accurate. They usually are much less effective for drawing or sketching, although some illustrators prefer them. Pad sizes range from 6 in. *6 in. (15cm) to cover 3 ft* 4 ft (0.9m *1.2m), with the most popular sizes being 12in. *12in.(30cm). Most are opaque, but transparent or translucent surfaces also are available to allow underlighting, especially useful for x-rays and some tracing. In some cases, digitizing pads are used as a substitute for a mouse, although most users have both for convenience.
Digitizers excel at high-resolution input of spatial data. CAD (computer aided design) programs rely on digitizers as a primary tool for gathering data because they do extremely well at high-resolution copying of existing plans, drawings, or sketches. However, they tend to be less effective than a mouse as a primary pointing device. For illustrators, they will have major uses for sketching directly into graphics packages and for development of models in CAD programs , which then can be developed into maps, diagrams, blueprints, and three-dimensional models.

Because gaging is a vital part of statistical process control (SPC), a new generation of electronic instruments has been produced. These instruments incorporate a liquid crystal display (LCD) and are capable of interfacing with a data collection device. Both inch and metric units are incorporated in one tool. The electronic feature is available on calipers, height gages, depth gages, and micrometers.