A NEW HAMPSHIRE MINERAL SPECIES DISPLAY

T.J. Mortimer, 3 Roberts Rd. Amherst, NH 03031

A regional, all inclusive, mineral species display presents several unique problems for the exhibitor. The most challenging of these problems is the wide range of specimen sizes that must be accommodated. When available, the exhibitor will usually prefer to utilize larger specimen examples. However, a comprehensive regional species display must include specimens with crystal sizes of a few millimeters or less. Accommodating the micro and macro in a single display offers a substantial challenge. A solution to this problem combines digital photography and a large computer monitor that is coupled with the real-life physical display. My twenty-year passion for New Hampshire mineral species motivated me to design and assemble a display to exhibit my collection. In addition to showing my micro-minerals as well as larger specimens to the viewer, I desired to make my display a permanent work. The following parameters evolved as the criteria for my display case design:

· The specimen images on a display monitor will be correlated to the physical specimens in the display case.
· The user will be allowed to interact with the display in the selection of species and analytic data to view.
· The display will be permanent. It will be sealed from un-authorized access and the accumulation of dust.
· The display size and weight will be such that it can be lifted and transported by a single person.
· The ordering of the minerals will be alphabetical (following the tradition of most regional species lists).
· The mineral ordering will be flexible, easily modified to accommodate the addition of new species, or the re-identification of existing specimens.

A 44” x 30” x 2” wall mount display case has been constructed that satisfies the above design specifications. The empty weight of the case is 25 lbs. It has shelf space for 308 thumbnail size specimens. Each mineral is mounted on a 1.25 inch square, one-half inch thick, clear acrylic block. These acrylic blocks have two holes in the rear. One hole accommodates a mating, snug-fit, bayonet plug that is affixed to the case backplane. This plug securely holds the specimen in its shelf position. The second hole aligns with a white LED (Light Emitting Diode) lamp wired to the case backplane. The complete backplane contains an 11 by 28 array of plug and LED pairs accurately aligned with the display shelves. A compartment in the case bottom houses the computer interface and LED driver electronics. A custom LED driver circuit board was designed to mate with a commercial RS232 computer interface board to power the LED lamp array. As each specimen image is presented on the monitor, a 9-bit code is sent to the display electronics defining which of the 308 LEDs to illuminate. The case backplane is also a custom design. It is an 11 row by 28 column copper tape matrix connecting the 308 LEDs. Standard HTML coded web pages are used to interface the user to the specimen images and the physical display. The web site, https://www.mindatnh.org, may be accessed to view the New Hampshire mineral species photos with or without the physical display.