A sensor and method of sensing dimensional changes, stress changes or pressure changes on a substrate uses a sensor in the following manner. Temporarily and non-destructively attach a piezoresistant sensor to a surface. The piezoresistant sensor has an electrically conductive elastic body having at least one pair of opposed ends, and the elastic body contains conductive nanotubes homogeneously distributed therein. The elastic body has at least one surface with two opposed ends and electrodes at each of the opposed ends. A current is passed through the elastic body between the two electrodes. The current passing through the elastic body is sensed (e.g., a voltmeter). A mechanical step is performed with or on the substrate, and the sensor measures changes in the current between the electrodes, indicating strain or pressure on the sensor.