In the scheme presented here, judic

In the scheme presented here, judicious use of three single-pole double-throw (SPDT) switches not only compensates for lead resistances but also ensures that discharge happens through a single microcontroller pin in every discharge cycle, thus eliminating the effects due to mismatch in the resistances of port pins. The measurement process is also modified in such a way that without performing an offset measurement, the effect of microcontroller port pin resistance on the measurement is eliminated. Compared to the scheme reported in [19] that uses four matched diodes and also requires four charge–discharge cycles for one measurement, the proposed method requires just two matched diodes and requires only three charge–discharge cycles for a measurement. Hence the update rate of the proposed sensor interface will be better than the sensor interface reported in [19].