A planar pressure transducer is disclosed which is useful for interposing between living tissue and a medical device that applies pressure to the tissue in order to estimate the pressure applied to a selected area of the tissue. A coupling pipe is interposed between the high-temperature reaction unit and the low-temperature reaction unit and transfers the first reaction material and the product created with the reaction material between the high-temperature reaction unit and the low-temperature reaction unit. Operationally, when the tool starts to unscrew the spark plug from an engine head, an axial non-rotating force is applied to the electrical interface extension that helps prevent separating damage between the spark plug components. The second reference signal is generated by applying the group sequence hopping, if the first parameter indicates that the group sequence hopping is enabled and the third parameter indicates that the sequence hopping and the group sequence hopping are disabled.