Physicists at the Netherlands-based University of Twente have built artificial hairs like those found on the chirping insects, whose highly evolved sound detection helps avoid predators like spiders or wasps, according to research published this week in the Journal of Micromechanics and Microengineering.

"These sensors are the first step towards a variety of exciting applications as well as further scientific exploration," Marcel Dijkstra, a member of the Twente team, said in a statement. In addition to helping hearing impaired people, "We could use them to visualize airflow on surfaces, such as an aircraft fuselage."

Cricket hairs are fine-tuned to detect airflow with energies as small as--or even below--thermal noise levels, according to the research. For example, the wood cricket can perceive changes in the air current caused by the beating of another insect's wing. Each tiny hair sits in a socket on a cricket's appendages and can be directed independently of others. Airflow causes the hair to rotate in its socket, which in turn fires a neuron. This allows the cricket to detect low-level sound in any direction and use the collective information of sensors to act, according to the research.

Scientists have managed to produce a few hundred mechanical hairs that are longer than normal cricket hairs, which can measure 1 millimeter. The sensors are composed of thin layers of electrically insulating and conducting materials to form structured electrodes on a suspended membrane. The hairs, made of a photo-structurable polymer, are placed on the membrane.

The research is part of the European Union project CICADA (Cricket Inspired perCeption and Autonomous Decision Automata), a project to study and mimic biological concepts through technology.

Excerpt from www.news.com, 6/22/05