March 22, 2026 – La Jolla, CA – UCSD Advances Non-Contact Health Monitoring
Researchers at the University of California, San Diego have demonstrated a high-sensitivity PIR sensor capable of detecting breathing patterns through clothing, enabling non-contact monitoring of respiratory rate. The technology could be used for sleep apnea detection, infant monitoring, and remote patient monitoring without wearables.
The research, published in IEEE Transactions on Biomedical Engineering, uses a custom-designed PIR sensor with 10× higher sensitivity than standard PIR modules to detect the subtle thermal changes caused by breathing.
Technical Specifications
- Sensitivity: 0.01°C temperature resolution (10× standard PIR)
- Detection range: 0.5-2 meters (optimized for bedside monitoring)
- Breathing detection accuracy: 95% (compared to chest belt reference)
- Respiratory rate error: ±2 breaths per minute
- Sampling rate: 20 Hz
- Processing: On-device signal processing with machine learning
- Power consumption: 2 mA (optimized for wall-powered devices)
How It Works
The sensor detects the periodic temperature changes on the surface of clothing caused by exhaled breath and chest movement. When a person breathes, exhaled air is warmer than the surrounding environment (approximately 34°C vs. 22°C room temperature). The sensor detects this periodic temperature variation, and signal processing algorithms extract the breathing rate.
Key technical elements:
- High-sensitivity pyroelectric element: Custom lithium tantalate element with low-noise amplifier
- Optical filter: 8-14 µm bandpass optimized for human thermal emission
- Signal processing: Bandpass filtering (0.2-0.8 Hz for adult breathing) and machine learning classification
- Motion rejection: Algorithms distinguish between breathing and body movement
Test Results
In clinical trials with 50 subjects, the sensor demonstrated:
- Breathing detection rate: 95% in supine position (lying down)
- Breathing detection rate: 88% in seated position
- Respiratory rate accuracy: ±2 breaths per minute compared to chest belt reference
- Apnea detection sensitivity: 92% (breathing pauses >10 seconds)
- False positive rate: 3% (detected breathing when no subject present)
Performance was consistent across different clothing types (cotton, polyester, wool) and room temperatures (20-28°C).
Applications
Sleep Apnea Monitoring
The sensor could enable at-home sleep apnea screening without uncomfortable chest belts or nasal cannulas. A bedside sensor could monitor breathing throughout the night and alert users to potential apnea events.
Infant Breathing Monitoring
Parents could place a sensor near a crib to monitor infant breathing without attaching sensors to the baby. The non-contact approach eliminates the risk of entanglement or skin irritation.
Post-Surgical Monitoring
Hospital patients could be monitored for respiratory depression without wires or adhesive sensors, improving comfort and reducing infection risk.
Remote Patient Monitoring
Elderly or chronically ill patients could have their breathing monitored remotely without wearing devices, supporting independent living.
Limitations
The researchers acknowledge several limitations:
- Distance: Optimal detection range is 0.5-1.5 meters
- Position: Sensor must be positioned facing the subject’s chest
- Motion: Large body movements can interfere with breathing detection
- Clothing: Very thick or insulating clothing reduces signal
- Room temperature: Performance degrades when room temperature approaches body temperature
Commercialization Path
The research team has filed patents and is exploring commercialization options. Potential pathways include:
- Licensing to medical device companies: 1-2 years to market
- Consumer product development: 2-3 years to market (sleep monitors, baby monitors)
- Integration into existing devices: Smart speakers, bedside lamps
Several companies have expressed interest, including ResMed (sleep apnea), Philips (patient monitoring), and Owlet (baby monitoring).
Conclusion
UCSD’s high-sensitivity PIR sensor demonstrates the potential of infrared sensing beyond simple motion detection. By detecting subtle thermal patterns like breathing, PIR sensors could enable new classes of non-contact health monitoring devices.