ALTA Vibration Meters use an accelerometer to measure g-force on 3 axis and then determine speed and frequency. They can be set to only capture when a vibration occurs and sleep when no vibrations are present, or they can be set to measure at a given assessment interval regardless of whether a vibration has occurred. If set to always measure, the sensitivity can be further adjusted to filter out noise. The Vibration Meter will also report the duty cycle, or how long the sensor was measuring vibrations throughout the heartbeat. This industrial sensor features a solar cell with rechargeable battery.