One of the most important sensors in a mobile or wearable device can be a microphone. Without it, a telephone can’t hear you when you speak. Wearable devices can not only process spoken information, but can also work with ambient noises in the wearer’s environment, from heartbeats to audible alerts. As with most mobile electronic components, the race is on to develop mics that are smaller, lighter, more durable, and higher quality.
As reported in a new article in MEMS Journal, a company called Vesper is looking to disrupt the microphone market for mobile devices. They use a novel MEMS (microelectromechanical systems) technology that relies on cantilevered piezoelectric materials. (A piezoelectric material has the useful characteristic of producing an electrical current when a force is applied, or producing movement when an electrical current is applied.) The result is a much simpler structure than most microphone components, and according to the company, the Vesper mics have the highest signal to noise ratio in the business. The fabrication process is similar to that used to produce billions of radio frequency (RF) components for cell phones. The mics show extremely uniform performance characteristics, which means that designers will have to worry less about matching individual components when creating arrays; some smartphones now have as many as five microphones in an array to improve sound quality and improve ambient noise rejection.
Advances such as this will result in devices with small footprints, lower power consumption, and better performance. As the wearable device market grows, we can expect to see even more component improvements.