Wireless occupancy sensor — privacy-first occupancy sensing

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How wireless occupancy sensors work

A wireless occupancy sensor detects human presence and reports it wirelessly to controllers, gateways, or cloud platforms.

Sensing methods

PIR (passive infrared): detects motion via changes in infrared radiation.
Ultrasonic: emits sound waves and detects movement by return patterns.
Microwave: uses Doppler radar to detect motion through frequency changes.
Thermal / heat-based: measures relative heat signatures and motion heat patterns for presence and counting.

Wireless communications and mounting

Common wireless communications include Zigbee, Bluetooth Low Energy (BLE), Wi‑Fi, sub‑GHz RF, and proprietary mesh protocols. Typical mounting options are ceiling- or wall-mounted; detection ranges vary by technology and mounting height.

Key detection characteristics

Typical detection range: 10–40 feet depending on sensor type and mounting.
Mounting: ceiling-mounted for broad coverage, wall-mounted for corridors and focused zones.
Power: battery-powered for easy retrofit or wired for continuous operation.

Types & comparison: sensor technologies and protocols

Choose sensors based on accuracy needs, privacy concerns, and integration requirements. Below is a concise comparison of common sensor technologies and protocol tradeoffs.

PIR (passive infrared)

Accuracy: good for motion detection, less accurate for stationary occupants.
False positives: low with proper placement; can miss still occupants.
Privacy: anonymous—no imaging or audio.
Best use: restrooms, corridors, high-traffic spaces.

Ultrasonic

Accuracy: detects small movements; better for covered areas with low motion.
False positives: more susceptible to vibrations and curtains.
Privacy: anonymous.
Best use: private offices, meeting rooms where motion may be subtle.

Microwave

Accuracy: high sensitivity and range; can detect through some materials.
False positives: higher if not tuned; can sense movement in adjacent spaces.
Privacy: anonymous.
Best use: large, open spaces where extended range helps.

Thermal / heat-based (Butlr)

Accuracy: strong at presence detection and occupancy counting, including stationary occupants when calibrated.
False positives: lower in many environments because pattern recognition separates human heat signatures from background.
Privacy: high—no images, no audio, anonymous heat maps only.
Best use: offices, meeting rooms, classrooms, space analytics where privacy and counts matter.

Protocol pros and cons

Zigbee

Pros: low power, mesh networking, mature in lighting controls.
Cons: requires gateway, limited bandwidth for analytics-heavy telemetry.

BLE (Bluetooth Low Energy)

Pros: ubiquitous support, low power, easy integration with smartphones and gateways.
Cons: range depends on environment; mesh support improving but varied.

Wi‑Fi

Pros: high bandwidth, direct cloud access.
Cons: higher power, may reduce battery life, requires strong network planning.

Sub‑GHz RF / proprietary mesh

Pros: long range, very low power, robust mesh for large deployments.
Cons: vendor lock‑in; may require specific gateways or controllers.

Key features to evaluate

When comparing wireless occupancy sensors, prioritize these attributes to meet operational and integration goals.

Coverage & accuracy: square footage per sensor and detection angle.
Presence vs motion sensing: ability to detect stationary occupants.
Battery life vs wired power: expected years of battery operation or constant power options.
Integration capabilities: compatibility with lighting controls, BMS, cloud APIs, and protocols used by your site.
Installation ease: mounting hardware, wireless commissioning, and calibration tools.
Analytics & reporting: real-time counts, dwell time, heat maps, and exportable datasets.
Certifications and standards: electrical safety, radio certifications, energy codes (e.g., ASHRAE recommendations).

Common spec ranges to expect

Detection coverage: 100–1,500 sq ft per sensor depending on mounting and technology.
Detection angle: 90°–360° depending on lens and placement.
Response time: sub-second presence detection for lighting control; seconds for analytics updates.
Battery life: 2–10+ years depending on sampling rate and wireless protocol; wired options remove battery constraints.

Applications & use cases

Wireless occupancy sensors are used across facility types to reduce energy use and improve space utilization.

Offices and open-plan areas: automated lighting and desk-use analytics.
Meeting rooms and huddle spaces: presence-triggered AV and HVAC adjustments; room booking accuracy.
Classrooms and lecture halls: lighting and ventilation control based on occupancy.
Restrooms and corridors: demand-based lighting to meet code and reduce runtime.
Retail and hospitality: zone-level traffic counts and dwell analytics for layout optimization.

Energy code & savings: occupancy sensors are often referenced in code guidance and can deliver typical lighting energy savings of 20–60% depending on baseline controls and occupant behavior. When combined with HVAC setbacks, total energy reductions increase further.

Privacy, reliability, and accuracy — why technology choice matters

Privacy is a growing procurement requirement. Camera- or microphone-based solutions can create legal and comfort issues for occupants. An anonymous occupancy sensor avoids image or audio capture while still delivering reliable presence and counting.

Butlr’s heat-based wireless occupancy sensor uses thermal pattern analysis to detect and count people without capturing identifiable imagery or sound.

Preserves occupant anonymity by design.
Improves detection of stationary occupants compared to PIR.
Reduces false positives with heat-pattern filtering.

For facilities managers and compliance teams, choosing a privacy-forward sensor simplifies stakeholder acceptance and reduces policy friction.

Integration & installation (quick how-to)

A straightforward wireless installation minimizes downtime and labor costs. High-level steps are outlined below.

High-level steps

Survey and plan: map coverage, mounting heights, and expected ranges for each sensor type.
Choose network architecture: select gateways or hubs that support your chosen protocol and integrate with lighting/BMS.
Mount sensors: typical ceiling heights 8–15 feet for offices; ensure clear line-of-sight for thermal sensors where possible.
Commission: add sensors to the mesh or gateway, set zones, calibrate sensitivity, and test control logic.
Integrate: connect to lighting controls, BMS, or cloud analytics via supported protocols or APIs; verify scenes and schedules.

Installation tips

For retrofit projects, prioritize battery-powered wireless sensors to avoid drywall or ceiling work.
Plan gateway placement for RF coverage and minimum hops to each sensor.
Use site commissioning tools and analytics to validate coverage and reduce blind spots.

Integration options include direct lighting control (DALI, 0–10V, relay), BACnet or Modbus for BMS, and cloud APIs for analytics and enterprise dashboards. Butlr provides platform integrations, developer APIs, and system documentation to streamline connectivity.

Specs & ordering guide

Key specs to request on a product card and questions to answer before purchase.

Model number and form factor
Detection coverage and accuracy (square feet and percent accuracy)
Wireless protocol(s) supported
Power options: battery type and expected life or wired voltage
Mounting method: ceiling/wall, degrees of freedom
Environmental ratings: temperature, IP rating if needed
Certifications: FCC, CE, UL, energy-code compliance
Warranty and support terms

Quick buyer checklist

Does the sensor detect stationary occupants?
Is the protocol compatible with my control systems?
What is the expected battery life at my telemetry rate?
Are privacy and data-export terms acceptable to legal/compliance?
Do I need gateways, and how many per floor?

For model options and spec sheets, see Butlr wireless sensors and Butlr wired sensors, and contact sales for batch pricing or reseller options.

Case studies & ROI snapshot

Typical pilot and roll-out results demonstrate energy and operational benefits.

Lighting runtime reductions of 30–55% after occupancy-based controls are enabled.
HVAC setback savings often add another 10–30% in conditioned spaces when integrated with schedules.
Space-utilization improvements leading to desk consolidation or better scheduling.

Short ROI example: a mid-size office with 1,000 fixtures can see payback in 12–36 months when combining lighting and HVAC savings, incentives, and reduced maintenance. For full case studies and an ROI calculator, request a demo or explore Butlr case studies and ROI tools.

FAQs

What is a wireless occupancy sensor?

A device that detects presence and transmits that information wirelessly to control systems for lighting, HVAC, or analytics.

How do wireless occupancy sensors save energy?

By turning off or dimming lights and adjusting HVAC based on real-time occupancy, reducing unnecessary runtime.

How are wireless sensors powered and what is battery life?

Options include battery power (2–10+ years depending on sampling and comms) or wired power for continuous operation.

Are wireless occupancy sensors compatible with existing lighting controls?

Many sensors integrate with common control standards (DALI, 0–10V, relay) and building protocols (BACnet). Check protocol compatibility before purchase.

How do Butlr sensors protect privacy?

Butlr uses anonymous, heat-based sensing—no cameras or audio—producing non-identifiable heat patterns for counts and presence.

What is the installation time for a typical office?

Small pilots can be installed and commissioned in a day; larger floors typically commission over several days depending on scope and integration complexity.

Call to action

Ready to evaluate a wireless occupancy sensor for your building? Request a demo or a quote to see how anonymous, heat-based sensing can lower energy costs, improve space utilization, and simplify privacy compliance. Contact Butlr sales, schedule a demo, or download spec sheets and installation guides to get started.

Wireless occupancy sensor — accurate, privacy-first occupancy sensing