Reflective sensor distinguishes colours

Hot on the heels of EMX Industries` colour intensity sensor, comes a colour sensing technology from another US manufacturer, Optek Technology, which claims that it will bring a new level of accuracy to automated colour detection.

Optek`s high-resolution sensor combines a white-light LED and a reflective colour sensor in a tiny plastics housing. The LED (which adjusts itself automatically to minimise the effects of non-uniform ambient lighting) illuminates the surface of the object being sensed, while the sensor measures the HSL (hue, saturation, luminance) value of the light reflected from the surface.

The sensor processes the HSL value to distinguish between different colours and intensities. Extra electronics can be incorporated to enhance the processing power.

The new sensor was first seen at the Sensors Expo in Chicago in June, where it was shown sorting M&M sweets automatically by colour as they passed through a tube. The technology is already being implemented in several commercial applications, including a pill-sorting machine, and an appliance that differentiates between different favours of coffee by identifying the colour of a ring on the filter pack.