Passive Contactless Vitals: Health Monitoring Without Wearables
Many elderly individuals refuse to wear smartwatches or health devices continuously. Passive contactless vitals monitoring uses two complementary technologies — mmWave radar for standoff detection and a ballistocardiography pressure mat for high-accuracy sleep monitoring — with no body contact required.
Technology 1: HLK-LD2410 mmWave Radar
HLK-LD2410 (400–600 THB) is a 24GHz presence sensor detecting both occupancy and micro-motions (breathing, heartbeat micro-vibrations) at up to 6m. The LD2450/LD2461 variants add multi-target tracking and respiration rate estimation. Mounted 1–1.5m above the bed and integrated via ESPHome UART, it provides breathing detection at ±2 breaths/min accuracy.
Technology 2: Ballistocardiography (BCG) Pressure Mat
BCG measures cardiac pulse force through pressure sensors under the mattress. A DIY implementation uses PVDF piezoelectric film (800 THB) or four load cells at bed legs with HX711 ADC (600 THB) sampled at 100–200 Hz by ESP32. A bandpass filter (0.5–5 Hz) isolates the heartbeat signal; peak detection yields beat-to-beat intervals and heart rate. The Withings Sleep Analyzer (4,500 THB imported) is the commercial option with FDA-cleared sleep apnea detection.
Parameters Monitored
Heart rate (BCG, ±3 bpm at 85th percentile), respiration rate (LD2410, ±2 /min), presence and movement count, and HRV (RMSSD from inter-beat intervals). Irregular RR intervals trigger atrial fibrillation screening at 82% sensitivity.
Morning LINE Health Report
Every morning at 07:00, Home Assistant sends a summary to family LINE: overnight heart rate (mean, min, max), respiration rate, waking count, 7-day HRV trend, and any arrhythmia flags — giving family members actionable health data without requiring the elderly person to use any app.