A scientist has developed a new design for ultra-thin capacitive sensors that have the least possible resistance to motion.
Created by acoustic researcher Professor Ron Miles at Binghamton University, New York, the thin and flexible sensor design is ideal for sensing sounds, he claims, because it can move with the airflow made by even the softest noises.
This, he says, addresses issues with accelerometers, microphones and many other similar sensors that don't respond well to sounds. But a sensor that is able to move with the air is able to tell when a sound is present and which direction it is coming from.
"The goal was to create a sensor that only resists gravity," said Miles. "The sensor needed to stay connected to the device but other than that, I wanted it to move with even the slightest sounds or movement of the air."
It hasn't previously been feasible to use capacitive sensing on extremely flexible, thin materials because they've needed to resist electrostatic forces that can either damage them or impede their movement.
But Miles' new platform overcomes this by providing a way to detect the motion of extremely thin fibres or films by sensing changes in an electric field, all without the use of a magnet as previous designs have required.
"Researchers want the sensor to move with small forces from sound, without being affected by the electrostatic forces," Miles added. "Because the sensor is at a 90-degree angle from the electrodes, the electrostatic forces don't affect its movement."
Miles explained that this is a critical part of the design because in order to be effective, the sensors need to have a high bias voltage, that is, the voltage required for a device to operate. Then the sensitivity of the sensor increases with a high bias voltage.
This design means that capacitive sensors, such as the ones used in smartphones, could be both smaller and more efficient.
"The way the sensor is designed now means that it has a nearly constant potential energy but can also return to its equilibrium after large motions," he added.
Miles's functional designs are currently patent pending.
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