Needle gauge

A moving-coil panel meter: a printed scale under glass, a thin needle that swings past the mark and settles, a lamp for the bands and a small LCD for the exact reading.

Take a reading: each needle swings past its mark and settles. A value past the scale rests on the stop. The glare and the needle’s shadow stay where the lamp puts them.

• The element is a role="meter" named by its label, with aria-valuemin, aria-valuemax, aria-valuenow and an aria-valuetext that carries the unit and the band: “84 degrees Celsius, in the warning band, 80 to 90”.
• It takes no focus and needs none: there is nothing to operate. The face, the needle and the LCD are its picture and are hidden from assistive technology.
• Bands are printed in ink — hatched for warning, solid for alarm — and the lamp by the name lights amber or red: position, print and light, never colour alone.
• Reduced motion: the needle jumps to the reading; the LCD, the lamp and the words are exactly the same.