In some embodiments, an apparatus can be configured to detect gas usage. The apparatus can include: (a) a processing module configured to run on a computational unit; and (b) a sensing unit configured to be coupled to a gas regulator, the sensing unit having: (1) at least one acoustic sensor configured to detect two or more acoustic signals produced by the gas regulator and convert the two or more acoustic signals into one or more first data signals; and (2) a transmitter electrically coupled to the at least one acoustic sensor and configured to transmit the one or more first data signals to the computational unit. The processing module is configured to use the one or more first data signals to determine the gas usage. Other embodiments are disclosed.