Knobs have both inner and outer glow

Although many consumer products use soft-touch pushbutton controls for cost, size, and aesthetics, many applications still require a more substantive and tangible control knob, as a pair of recent introductions demonstrates (Picture). Selco Products has introduced two lines of shaft-push-on and collet-control glowing knobs. One line uses a fluorescent coating, which UV light "charges," and the other uses a phosphorescent coating, which either daylight or artificial light charges. The knobs are black, and a white indicator is optional; other colors are available on request. The standard knob sells for 43 cents (1000).

In a more complex scheme, Elma Electronic has introduced knobs that use surface-mounted LEDs on a flexible pc-board strip inside the dial, which is made of a light-guide material. You can get these 23- to 30-mm knobs with a skirt with a single viewing window, so that only one character shows through at a time. The LEDs are available in a range of colors, and the knobs sell for approximately $2.50 (large quantities).

Selco Products, 1-714-917-1333, www.selcoproducts.com.

Elma Electronic Inc, 1-510-490-7388, www.bustronic.com.