From Millimetre Wave to Meaningful Decisions

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Occupancy sensing has quietly become one of the most important building blocks in smart offices, smart campuses, and smart cities. Not because the sensors themselves are flashy — but because what they unlock is transformational.

When done properly, occupancy data becomes the connective tissue between space, people, energy, security, and experience. When done badly, it becomes just another dashboard no one checks.

In this post, we’ll break down:

And how it can be orchestrated with systems like access control, BMS, AV, and workplace platforms

The types of occupancy sensors available today (including millimetre wave)

How connectivity and protocols shape what’s possible

Where edge vs cloud processing really matters

How occupancy data fits into the 360 Smarter Stack

And how it can be orchestrated with systems like access control, BMS, AV, and workplace platforms

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1. What Do We Mean by “Occupancy”?

At a basic level, occupancy answers one question:

Is someone here?

But modern systems can answer much richer questions:

• How many people are here?
• How long do they stay?
• Are they sitting, standing, or moving?
• Is the space being used as intended?
• How does real usage compare to bookings?

This evolution — from binary detection to contextual insight — is what makes occupancy sensing strategic rather than tactical.

2. Occupancy Sensor Technologies Explained

Not all occupancy sensors are created equal. Choosing the wrong one can limit your entire smart building strategy.

Passive Infrared (PIR)

Best for: Basic motion detection

Limitations:

• Struggles with stationary occupants
• No people counting
• Easily fooled by heat sources

PIR is cheap and common, but it’s increasingly inadequate for modern workplaces.

Ultrasonic Sensors

Best for: Detecting subtle movement

Limitations:

• Can trigger false positives
• Poor spatial accuracy

Useful in enclosed rooms, but not ideal for analytics-heavy use cases.

Camera-Based Sensors (Vision AI)

Best for:

• Accurate people counting
• Behaviour analysis
• Space utilisation

Challenges:

• Privacy concerns
• Higher processing requirements
• Regulatory complexity

Vision systems are powerful — but they require careful governance and often edge processing to avoid sending identifiable data to the cloud.

Millimetre Wave (mmWave) Sensors

Best for:

• Presence detection (even when people are still)
• Fine-grained movement tracking
• Privacy-safe occupancy sensing

Why mmWave is a game changer:

• Detects micro-movements like breathing
• Works in darkness and through some materials
• Does not capture images

Millimetre wave sensors are rapidly becoming the gold standard for modern occupancy sensing, especially where privacy and accuracy both matter.

3. Connectivity: How Occupancy Data Moves

Sensors are only as useful as their ability to communicate reliably.

Common Connectivity Options

• Wired (Ethernet / PoE): Reliable, secure, ideal for fixed installations
• Wi-Fi: Flexible but power-hungry
• Bluetooth Low Energy (BLE): Good for short-range and battery-powered sensors
• LoRaWAN: Excellent for low-power, low-bandwidth telemetry across large estates
• Cellular (LTE / NB-IoT): Useful where no infrastructure exists

The right choice depends on:

• Power availability
• Data frequency
• Latency requirements
• Scale of deployment

4. Protocols: The Language of Smart Buildings

Connectivity moves data. Protocols give it meaning.

Common Protocols in Occupancy Systems

• MQTT: Lightweight, event-driven, ideal for real-time occupancy
• BACnet: Still dominant in traditional BMS environments
• REST / Webhooks: Useful for integration with cloud platforms
• Zigbee / Thread: Common in sensor networks
• Matter (emerging): Promising, but still early for commercial estates

A key architectural mistake is locking occupancy data into a single vendor protocol. In the 360 Smarter Stack, openness matters.

5. Edge vs Cloud: Where Should Occupancy Intelligence Live?

This is not an either/or decision — it’s a design choice.

Edge Processing

Best for:

• Real-time decisions (lighting, HVAC, AV wake-up)
• Privacy-sensitive processing
• Reduced latency and bandwidth

Example:

A meeting room lights up, HVAC ramps, and the Teams Room wakes before the user presses a button.

Cloud Processing

Best for:

• Portfolio-wide analytics
• Trend analysis and forecasting
• Space optimisation and reporting

Example:

Identifying that a “high-demand” floor is actually underutilised every Friday.

The Smart Approach: Hybrid

• Edge handles immediate control
• Cloud handles learning, optimisation, and strategy

This aligns perfectly with the Data & Context and Integration Layer of the 360 Smarter Stack.

6. Orchestrating Occupancy Into the 360 Smarter Stack

Let’s map occupancy sensing across the stack:

Vision & Value

Occupancy data should answer business questions:

• Can we reduce real estate?
• Are teams using collaboration spaces effectively?
• Where is energy being wasted?

User Experience

• Rooms that “just work”
• No more ghost bookings
• Comfortable environments without manual adjustment

Data & Context

Occupancy becomes far more powerful when combined with:

• Time of day
• Booking data
• Team or department usage patterns
• Environmental data (CO₂, temperature)

Integration Layer

This is where the magic happens:

• Occupancy → BMS
• Occupancy → AV systems
• Occupancy → Workplace apps
• Occupancy → Analytics platforms

APIs and event-driven architecture matter here.

Systems & Devices

Sensors, gateways, controllers, edge compute — all selected as part of a coherent ecosystem, not bolt-ons.

7. Linking Occupancy With Access Control

One of the most underused opportunities is occupancy + access control.

Examples:

• Validate room usage against badge access
• Detect tailgating or abnormal patterns
• Auto-release rooms if no access event occurs
• Improve safety reporting during evacuations

When access control provides identity and occupancy provides presence, you gain situational awareness, not just data.

8. Common Pitfalls to Avoid

• Deploying sensors without a clear use case
• Treating occupancy as “just facilities data”
• Ignoring privacy and governance early
• Over-centralising everything in the cloud
• Locking into proprietary platforms

Smart buildings fail when sensing is divorced from decision-making.

Summary: Occupancy Is Not About Sensors

Occupancy sensing is not about PIR vs mmWave.

It’s not about dashboards.

It’s not even about technology.

It’s about understanding how space is actually used — and responding intelligently.

In the 360 Smarter Stack, occupancy is a foundational signal. When orchestrated properly, it enables better experiences, lower costs, smarter energy use, and buildings that adapt to people — not the other way around.

Explore our Foundation and Practitioner Courses to start building capability with the 360 Smarter Stack.