Odds and ends: LEDs, waveguides, data acquisition

E-mail

Good reasons exist for not using blue illumination, including the human eye’s difficulty in focusing blue light. Aside from blue-lighted automobile gauges, I’m unaware of any professional-quality test instruments that use blue LEDs as illuminators or indicators. Let’s hope that function continues to triumph over fashion, and that the human-factors engineers beat the blue daylights out of the stylists.

From the Better Health department: If you’ve ever bloodied your knuckles while bolting up a waveguide, chances are you’ll cheer the arrival of a new technology that enables fabrication of waveguides and other structures on substrates. Developed in conjunction with researchers from the University of Colorado at Boulder, the PolyStrata process uses a polymer molding material deposited in a layer surrounding electroplated metallic structures. Repeated deposition of plating and molding materials produces 3-D structures filled with the polymer. Dissolving the polymer yields microminiature waveguides and air-dielectric transmission lines.

The technology appears well-suited to building systems on a substrate that incorporate everything up to and including an antenna array. From a test-engineering viewpoint, adding test connectors might prove challenging, and you’d do well to incorporate built-in test equipment (BITE) onto the substrate. But you’ll never skin your knuckles again.

From the Low Budget department: If you’re a student, an impoverished experimenter, or a test-instrument collector, you may have accumulated one or more instruments that include an IEEE 488 (GPIB) interface. While several manufacturers offer highly capable data-acquisition and control packages (e.g., National Instruments’ LabView), the software alone may cost more than your entire instrument collection. As an alternative, you can download EZGPIB, a freeware GPIB, RS-232, and TCP/IP program that features a Pascal-like programming language.

Developed by Ulrich Bangert, holder of German amateur radio license DF6JB, EZGPIB runs on an IBM-compatible PC that’s equipped with either of two GPIB interfaces (see “More odds and ends” below) and uses Windows 2000 or a more recent Microsoft operating system. You’ll need to become familiar with your instrument’s GPIB programming commands, though. Give EZGPIB a try!