Descriptif

In the context of the generalization of Smart Cities, there is a definite trend to monitor locally all kinds of phenomena, such as pollutant concentration, temperature and hygrometry, state of the road, trajectories and weights of vehicles, water quality in drink water pipes or for plant watering, water leakages, nutrients and contaminants in the soil, housing energy consumption… The wealth of available information, typically collected by (wireless) sensor networks or by (often more industrial-grade) SCADA systems, is then used to act on the phenomena globally (for instance policies to improve air quality or traffic) or locally (for instance water purifiers, micropumps…)

The transducer is the tool which converts the phenomena into a quantifiable information to be provided to the user (a sensor), or alternately converts a command from the user into an action on an external phenomena (an actuator).

The module first discusses the various principles behind transduction: electrical, optical, mechanical, chemical, biological, optoelectronic, electrochemical, electromechanical… with insight into the applications and the requirements for such systems.

Transducers are ubiquitous today: they can be counted by the dozen even in the most common place consumer goods, such as a dishwasher, by the thousands in high tech systems such as a car or a plane.

As a consequence, there is a definite effort to reduce cost and size of transducers. New technologies come in play to enable such evolution: micro and nanotechnologies.

The module presents case studies of the application of micro and nanotechnologies to transducer devices, highlighting the most prominent tools and strategies for micro and nanotransducer fabrications.

The impact of the move to micro and nanotechnologies for transduction is that the acquisition and command electronics have to evolve also. It also opens new opportunities, such as heavy multiplexing, but increases the need for signal processing, for instance to compensate for small signals. The module looks into some of the challenges of transducer end-to-end integration, at hardware and software level, from the lab to real life deployments.

The topic of calibration (namely how the outputs of the transducer correlates with the phenomena monitored or driven by the transducer) is also addressed in depth, as it is both critical to transducer operation and often overlooked.

Finally, reducing size and cost, the reliability of the transducers tends to be reduced also. The module addresses the concept of reliability at the multiscale, from system level to component level.

Notably, the focus is on the mechanisms of ageing and failure in micro and nanotransducers: first how to diagnose and then characterize these mechanisms, then how to mitigate them at the micro and nanoscale, then at the system scale.