Crickets use sensitive hairs on their cerci (projections on the abdomen) to detect predators. For these insects, air currents carry information about the location of nearby predators and the direction in which they are moving.
University of Twente researchers used the same principle to create a new kind of “camera,” one capable of imaging entire flow patterns rather than measuring flows at a single point. The cricket hairs are mimicked using microtechnology. The hairs themselves are made of a type of epoxy, which is attached to a flexible suspended plate. The plate acts as a capacitor, whose capacitance varies with movement. Measuring that variation gives you information about the movement.
Using an entire field or array of such fine hairs, it is possible to identify patterns in the flow, in much the same way as complete images are formed from the individual pixels detected by chips in cameras.
With Frequency Division Multiplexing (FDM), the measured signal is not delayed while in transit, it is not difficult to synchronize the individual sensors, and the sensor array can easily be expanded without sacrificing performance.
The hardware involved is less complex than that required by other technologies. Looking ahead, the researchers believe that it will ultimately be a relatively simple matter to integrate the sensors and the hardware, resulting in a “camera” that is capable of imaging flow patterns. The technology could then be used as a motion detection system in robots.
Also: Learn about a wide-field optic for long-range motion detection.
