Graphene/high-oriented polypyrrole foam enables new-type ultrasensitive micro-distance detection

Micro-resolution range finder (MRRF) is an essential tool in various cutting-edge fields such as shooting macro, precision instrument, vibration monitoring and micro-collision-avoidance systems. Desirable MRRF requires micro-scale precision, high accuracy, rapid response, and long-term cycling stability. Yet conventional MRRFs based on optical feedback, precise machining, piezoelectric effects and magnetostriction are still limited by complicated designs, precise sequence of tasks, and cumbersome device volume. As such, for the first time, we present a new-type of micro-distance sensor consisting of reduced graphene oxide/high-oriented polypyrrole foam (rGO/HOPPyF) for MRRF. Based on the distance-resistance property of the as-prepared foam, the micro-distance sensor has shown advantages of easy operation, low cost, miniaturized device. Here, large-rate resistance change and great mechanical stability are realized in rGO/HOPPyF, thus allowing precise and accurate micro-distance detection. The micro-distance sensor demonstrates ultrahigh sensitivities of 386.7, 1260 and 546.7 m−1 within the step-length regions of 10 ~ 80, 80 ~ 290, 290 ~ 570 µm, respectively. Remarkably, both the precision and accuracy of our sensor are superior over those of the commercial micrometer and laser rangefinders, providing a new technological advance towards practical MRRF.