An energy harvesting device for accurately counting rounds fired by a firearm comprises a piezoelectric element for mechanical coupling to the barrel of the firearm. The piezoelectric element may produce a voltage waveform in response to the mechanical vibrations from a round passing through the barrel, which may power a microcontroller. The microcontroller may determine the rate of change of the voltage waveform to determine if a live round was fired. The microcontroller may be in communication with an RFID chip. The microcontroller may read the value on the RFID chip, increment the value of the RFID chip in response to being turned on by the voltage waveform, and then store the incremented value on the RFID chip. An armorer may remotely check the value of the RFID chip.