Novel adaptive algorithms and practical examples of its realizations in various self-adaptive smart sensors and sensor systems with parametric adaptation are described in this article. The adaptive algorithms are based on novel methods of measurements such as modified method of the dependent count with programmable relative error and non-redundant time of measurement, and the method with non-redundant reference frequency. Equations of measurements for these methods are given and decision rules formulated. Some practical examples of self-adaptive smart sensor systems based on the Universal Frequency-to-Digital Converter (UFDC), Universal Sensors and Transducers Interface (USTI) integrated circuits, and ultra-low-power microcontroller are described in the paper