FastDrop: Capacitive sensor for in-flight droplet volume measurement
Loading...
Author
Limacher, R.
Shynkarenko, Y.
Orawez, G.
Bitterli, S.
Cristofolini, P.
Grivon, D.
Cattaneo, S.
Valentin, T.
Pache, C.
Crivelli, F.
DOI
Abstract
The FastDrop sensor is a compact capacitive sensing system designed to quantify the volume of small, in-flight droplets, addressing a key gap in liquid handling in the sub-microliter range, where conventional gravimetric methods lack sensitivity and optical solutions, despite their high accuracy, are difficult to integrate. FastDrop’s operating principle is based on measuring capacitance changes as droplets pass through the electric field formed by PCB-embedded electrodes. Two sensor variants were developed - one using a high-performance lock-in amplifier and another based on low-cost in-house electronics - both benefiting from scalable, low-cost PCB fabrication and adaptable electrode geometries. The sensor demonstrates a fast response time, allowing the detection of individual droplets which are only a few ms apart, thereby supporting dispensing frequencies up to 300 droplets per second. These results demonstrate the strong potential of the FastDrop sensor for high-throughput, low-volume droplet monitoring in automated liquid handling systems.
Publication Reference
CSEM Scientific and Technical Report 2025, p. 43–44
Year
2025