Men addressing the question on how to operate sensors in a remote environment, i.e., in non-accessible places, the issue of reliability becomes of extreme importance. Especially in the case where miniaturisation is essential, often the physical geometries become that small that the sensor performance degrades to yield only very weak signal levels. Matching circuits are an essential element. Monitoring physical quantities from a remote and difficult to access location requires high standards for the sensors and their circuits involved: it is essential that the data remains reliable at all times. This is a hard requirement, and many sensors used in such applications cannot cope with such severe specifications, as there are: low drift, high stability in time, immunity to cross sensitivies, etc. This paper focuses on a double solution: first by adding circuitry improving the intelligence of the entire sensor system. Secondly, it is shown how the sensor design in itself can be modified to improve the interface circuit performance. An essential element is the addition of built-in self-test features to verify the correct operation of the sensor at any given moment in time. Crucial in these novel developments is that the measurand itself is used to verify the operation of the sensor, and not a related actuation as is done in many existing devices.