Introduction
With aging populations, technology for elderly care is increasingly important. PIR sensors offer a privacy-preserving way to monitor activity and detect falls.
Applications in Elderly Care
Fall Detection
A fall has a characteristic signature: rapid movement followed by prolonged inactivity. PIR sensors can detect this pattern and trigger an alert.
Activity Monitoring
Track daily patterns: time spent in bed, trips to bathroom, kitchen activity. Deviations from baseline can indicate health issues.
Wandering Detection
For dementia patients, detect if they leave the bed at night or exit the home.
Medication Reminders
Detect if person visits medication area at scheduled times.
Fall Detection Algorithms
Modern fall detection using PIR involves:
- Detecting a rapid, high-amplitude signal (the fall).
- Observing subsequent lack of motion (prolonged inactivity).
- Comparing to normal activity patterns.
Machine learning models trained on fall vs. normal activity data can achieve >90% accuracy.
Sensor Placement
- Ceiling-mounted in each room: Provides coverage without being intrusive.
- Bedroom: Monitor bed occupancy and nighttime movement.
- Bathroom: High-risk area for falls.
- Hallways: Track movement between rooms.
Integration with Alert Systems
When a fall is detected, the system can:
- Send alert to caregiver’s smartphone.
- Trigger an audible alarm.
- Call emergency services (with confirmation).
- Open a two-way communication channel.
Case Study: Assisted Living Facility
An assisted living facility installed PIR sensors in each resident’s apartment. Over one year, the system detected 23 falls, with 96% accuracy. Caregivers were alerted immediately, reducing response time from hours to minutes.
Privacy Benefits
Unlike cameras, PIR sensors don’t capture images, making them acceptable to residents who value privacy. No one is “watched” – only movement is detected.
Challenges
- False positives: Dropping objects can mimic fall.
- Multiple residents: In shared rooms, distinguishing individuals is difficult.
- Pets: May cause false alarms.
Conclusion
PIR sensors are a valuable tool for elderly care, enabling independent living while providing safety monitoring. They are privacy-preserving, low-cost, and effective when combined with intelligent algorithms.