You’re asking for a detailed explanation of how acoustic sensors are used in wearables for the following purposes:

• Voice recognition: Enabling voice commands in smartwatches, earbuds, and AR glasses.
• Health monitoring: Detecting heart sounds, breathing patterns, snoring, etc., to analyze health status.
• Environment recognition: Detecting ambient noise levels to optimize noise cancellation features.
• Proximity sensing: Using ultrasound technology for gesture or distance detection in fitness bands.

Here’s a breakdown of each of these applications:

1. Voice Recognition:

• Smartwatches: In smartwatches, acoustic sensors (microphones) are primarily used to activate voice assistants (e.g., Siri, Google Assistant) and execute voice commands. This significantly improves convenience by allowing users to perform various tasks such as checking the weather, checking notifications, sending messages, and making calls using their voice without touching the watch screen. It is also useful in situations where it is difficult to use hands, such as during exercise or driving.
• Earbuds: In earbuds, acoustic sensors not only improve call quality but also enable voice control of various functions such as music playback control, volume adjustment, and activation of ambient sound modes. In particular, the latest earbuds offer more accurate and natural voice command processing through AI-based voice recognition technology.
• AR Glasses: In AR glasses, voice commands can be used to perform various functions such as information retrieval, navigation, and taking photos. By providing a voice interface along with visual information, it provides a more immersive user experience.

2. Health Monitoring:

• Heart Sounds: Analyzing heart sounds (heart murmurs) can monitor heart health. Certain heart conditions, such as heart valve disease and heart failure, exhibit characteristic changes in heart sounds, so detecting these changes can aid in early diagnosis.
• Breathing Patterns: Analyzing breathing sounds and patterns can detect signs of respiratory diseases such as sleep apnea and asthma. In addition, changes in breathing patterns can be used to measure stress levels or provide guidance for meditation and breathing exercises.
• Snoring: Detecting snoring sounds during sleep can assess sleep quality and indicate the possibility of sleep apnea.
• Other Bioacoustics: Research is being conducted on analyzing various bioacoustic signals, such as bowel sounds and blood flow sounds, to monitor health status.

3. Environment Recognition:

• Ambient Noise Level Detection: Real-time measurement of ambient noise levels can help protect users’ hearing. In noisy environments, it can automatically activate noise cancellation functions or guide users to limit noise exposure time. In addition, analyzing noise level data can be used to solve environmental problems such as creating noise maps and managing urban noise.
• Specific Sound Detection: Detecting specific sounds (e.g., siren sounds, baby crying sounds) can provide notifications to users. This helps ensure user safety and allows them to respond quickly to necessary situations.

4. Proximity Sensing:

• Using Ultrasound Technology: Some wearable devices use ultrasonic sensors to implement proximity sensing functions. They calculate the distance to an object by emitting ultrasound waves and measuring the time it takes for them to be reflected back.
• Gesture Recognition: Ultrasonic sensors can be used to recognize hand movements or gestures. For example, you can perform functions such as playing/pausing music and adjusting the volume by waving your hand.
• Distance Measurement: By measuring the distance to an object, you can provide notifications when approaching a certain distance or guide users to maintain a safe distance.

As such, acoustic sensors are used in various ways in wearable devices to enhance the user experience and help with safety and health management. They are expected to provide more intelligent and useful functions in the future by converging with AI technology. For example, they can provide more advanced services such as identifying the user’s emotional state through voice analysis and recommending music that suits the situation or providing meditation content for stress relief.