SparkFun Piezo Vibration Sensor - Small Vertical Cantilever Module

The sensor generates a high-voltage AC signal (up to ±90V) which must be attenuated. Connect a large-value resistor (e.g., 1 MΩ to 10 MΩ) across the sensor leads to create a voltage divider, lowering the peak voltage to a safe level (typically below 5V or 3.3V) for your microcontroller's analog input pin. Always verify the attenuated signal range with an oscilloscope before connecting to an ADC.

This cantilever-type sensor is optimized for low-frequency vibration detection. It has a resonance frequency of 75 Hz, where sensitivity peaks at 6 V/g. The usable frequency response extends up to its upper limiting frequency of 42 Hz (+3 dB point). It is most effective for detecting events and vibrations well below 100 Hz.

It is suitable for both applications. Its high sensitivity and AC output allow it to detect continuous, oscillatory vibrations (like machine imbalance) as a varying AC signal. For detecting discrete impacts or taps, you would typically monitor for signal peaks or thresholds exceeding a set voltage level in your code.

The sensor is designed for vertical mounting via its solder pins. Secure the base of the sensor firmly to your chassis or PCB, allowing the cantilevered film with the proof mass to move freely. Avoid constraining the film's movement, as this will dampen sensitivity. Ensure the operating environment stays within the -20°C to +60°C temperature range.