This is a sonic (sound-based), pocket-size measuring tool, accurate up to 3mm. It is useful for applications where you want to log the distances or find distances that are inaccessible, therefore measuring tapes, rulers, and callipers are out of the question! Since the ESP32 is such a tiny micro controller powered by a micro usb port, you can grab a small power bank, plug it in, and start measuring distances normally inaccessible with conventional means of measuring i.e. rulers.”