Piezo Liquid Sensor Design

I have a piezo-based wet/dry sensor concept that relies on tracking resonance changes in a PZT ceramic between 20 kHz and 500 kHz. When the tip is in air the vibration is high-Q with a large voltage swing; when any liquid covers it the amplitude drops, the Q-factor falls, and both phase and resonant frequency shift.

I now need an electronics specialist who can turn this working principle into a repeatable, field-ready solution. The job covers selecting the drive topology, designing the analog front-end, and implementing a small digital section that continuously excites the ceramic, samples the returning signal, and decides “wet” or “dry” in real time. Accuracy, low noise, and robust thresholding against temperature or viscosity changes are essential.

Deliverables
• Schematic, PCB layout, and BOM for the driver/sensing circuit
• Firmware (or FPGA logic) that excites, measures, and flags state changes
• Clear documentation: test setup, calibration method, and example data traces
• A brief report on expected performance limits (response time, sensitivity, lifetime)

I will supply mechanical constraints and the exact PZT part number once the project starts. If you have prior experience with ultrasonic transducers, impedance spectroscopy, or capacitive sensing, please highlight it—those skills map directly to this task.