Design and implementation of liquid droplet based motion sensing

This paper reports a liquid droplet based motion sensing system with advantages of simple fabrication, superior biocompatibility and binary signals. The sensor consists of a dielectric substrate and an array of microelectrodes patterned by surface micromachining techniques. In this sensing system, an ionic droplet behaves as the proof mass which responses to external applied acceleration. A lumped parameter model is built to compare the frequency response of such sensor with conventional solid proof mass accelerometers. Electrical signals detected by microelectrodes array are used to determine the applied acceleration based on droplet dynamics. Characterization of a prototype illustrates a good match between the predicted accelerations and the actual values.