Always-on MEMS mic uses sound energy to wake a system

July 04, 2016 // By Graham Prophet
Always-on MEMS mic uses sound energy to wake a system
Vesper Technologies (Boston, MA), a privately held piezoelectric MEMS company that began at the University of Michigan, has improved the acoustic experience with a wide range of consumer products via a patented piezoelectric MEMS platform. Vesper has now demonstrated the first commercially available quiescent-sensing MEMS device, providing designers the possibility of acoustic event-detection devices at virtually zero power draw at 3 µA of current while in listening mode.

This piezoelectric MEMS microphone — VM1010 — will allow designers to advance voice and acoustic event monitoring in their systems. See Figure 1 for the pin out of this IC.

Figure 1. The pin out of the VM1010 (Image courtesy of Vesper)

Matt Crowley, Vesper CEO told me that this quiescent-sensing MEMS microphone is the only device that uses sound energy itself to wake a system from full power-down. It is known that even when fully powered-off, batteries in smartphones and smart speakers naturally dissipate 40-80 µA, which is far more current than this device needs.

So a design using this technology will see no difference in battery-life for a system using the VM1010 in listening mode and a fully powered-down conventional system. See Figure 2 for specifications.

Figure 2. Key specifications for the VM1010 (Image courtesy of Vesper)

Even in sleep mode, this microphone preserves its very high signal-to-noise ratio (SNR) — which is needed for a wider acoustic range. In fact, there is absolutely no SNR penalty from going into low power, extending the distance of far field voice control in battery-powered systems. The following video shows the actual performance and capabilities like wake-on-sound:

When a designer embeds this device into a voice-powered TV remote control or smart speaker, it could allow you to turn on your device from across the room without having to push a button and without diminishing battery life. See the block diagram of the VM1010 in Figure 3.

Figure 3. Block diagram of the VM1010. (Image courtesy of Vesper)

This microphone employs a rugged piezoelectric transducer that is immune to dust, water, oils, humidity, particles and other environmental contaminants, making it suitable for deployments outdoors or in kitchens and automobiles. Completely waterproof, a second video shows the hydrophone capability of the VM1010. This opens up so many new markets and possibilities for designers.

An ideal feature of any design that uses this

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