Georgia Tech Builds Battery-Free Ultrasonic Smart Home Sensor
SoundOff uses a penny-sized notched metal disc that emits inaudible ultrasonic tones to trigger smart home automations without batteries.
Updated on Nov. 8, 2026 in Home Entertainment
A Georgia Tech engineering team led by Yibo Fu developed SoundOff, a battery-free sensing platform that detects ultrasonic sounds from attached door, drawer, or open-close mechanisms. The system could cost just a few cents to manufacture, according to the team.
Why it matters
SoundOff offers a low-cost, battery-free way to add sensing to everyday household objects, which could make smart home automation cheaper to deploy. The approach also shows how inaudible acoustic signals can carry specific instructions without any power source at the sensor itself.
The prototype uses a penny-sized metal disc on a 3D-printed base, with ultrasonic frequencies above 20 kilohertz that are inaudible to humans. Researchers created about 1,300 notch designs, but ultrasonic tones fade rapidly at roughly three feet, and it remains unclear how well lower-cost microphones would perform.
The players
Georgia Tech
Georgia Institute of Technology is a public research university in Atlanta known for its engineering programs.
Yibo Fu
Yibo Fu is the researcher who led the engineering team that developed the SoundOff sensing platform.
The details
When an attached door, drawer, or other item is opened or closed, a plastic tab strikes the notched metal disc and emits a hyper-specific ultrasonic sound. A microphone-equipped device picks up that frequency and runs custom software to carry out a particular automation.
Smart Home Context
SoundOff extends battery-free sensing research at Georgia Tech by using ultrasonic acoustics instead of radio or electrical signals. It positions passive, low-cost triggers as an alternative to conventional battery-powered smart home sensors.
Atlanta homeowners interested in smart automation could eventually see low-cost, battery-free triggers for doors and drawers, though the technology remains at the research prototype stage. The current system depends on a microphone-equipped device nearby, so it does not yet work as a standalone consumer product.
The takeaway
Sensing technology does not always require batteries or wiring; clever physical design can turn everyday objects into smart inputs. Readers should watch for consumer versions as the underlying hardware matures.
Further reading
For more on connected living, explore the Home Entertainment section.
Source note: This article includes information reported by BGR.
