The application specific paper describes a design approach for digital opto sensors and data acquisition systems. It is based on the Universal Frequency-to-Digital Converter (UFDC-1) working well with any frequency output sensors, for example, light- and color-to-frequency converter from TAOS. Such design approach lets significantly simplify the design process, reduce time to market and production price and produce digital opto (color and light) sensors and multi parameters sensors with high metrological performances. Practical examples of such digital sensors are given.