What is a wireless occupancy sensor?
A wireless occupancy sensor detects whether people are present in a room or space and sends that information to lighting, HVAC, or building management systems without requiring physical network cabling.
These sensors can be battery-powered or hardwired and communicate using protocols like Bluetooth, Zigbee, Z-Wave, or proprietary wireless links. Occupancy sensors enable automated control (on/off) and can support analytics such as space utilization and peak demand reduction. For many commercial buildings, the right sensor balances detection accuracy, privacy, installation complexity, and integration capability.
Sensor technologies compared — Thermal (Butlr) vs PIR vs Ultrasonic
Understanding sensor technologies helps you match a product to real-world conditions.
Thermal (anonymous, AI-driven)
How it works: senses heat signatures and motion patterns using thermal arrays and AI to infer presence and count occupants without capturing images.
Strengths: privacy-first, works in low-motion scenarios (e.g., seated meetings), better multi-person detection, and rich analytics for utilization and safety.
Typical trade-offs: slightly higher upfront cost than basic PIR but greater long-term value from analytics and fewer false negatives.
Passive infrared (PIR)
How it works: detects rapid changes in infrared radiation caused by movement of warm bodies across its field of view.
Strengths: low cost, low power, reliable for motion-based lighting control in many spaces.
Limitations: poor performance when occupants are sedentary or behind obstacles; limited people-counting capability.
Ultrasonic
How it works: emits ultrasonic sound waves and measures reflections to detect motion.
Strengths: detects motion around obstructions and in multiple directions.
Limitations: can be sensitive to HVAC turbulence and may produce false positives in busy environments; privacy neutral but less suited for analytics.
Hybrid sensors
Combine two or more technologies to reduce false positives/negatives. They can balance PIR’s low power with thermal or ultrasonic coverage but may still lack accuracy for multi-person analytics.
Why consider Butlr’s thermal sensors
Butlr combines anonymous thermal sensing with AI to provide accurate presence detection and people counting while preserving privacy.
Key advantages include consistent performance in low-motion spaces such as conference rooms and libraries, anonymous analytics that surface utilization trends, and integrations that help optimize energy and space management.