Präsenzsensoren: German Guide to Presence Detection Sensors

Präsenzsensoren (German for "presence sensors") are electronic devices that determine whether one or more human occupants are currently present within a defined space, including the case where the person is sitting motionless, lying down, or sleeping with no visible movement, using millimeter-wave (mmWave) radar technology at 60 GHz (57–64 GHz) with 7 GHz of bandwidth to detect the micro-Doppler signature of human breathing at 0.2–0.5 Hz from ranges of 6–8 meters. A präsenzsensoren is fundamentally different from a passive infrared (PIR) motion sensor (Bewegungssensor), which only fires when a warm body moves across its field of view and is unable to detect a stationary person. A modern 60 GHz mmWave präsenzsensoren achieves a stationary-occupant true positive rate above 99% in controlled testing and above 95% in real-world deployment, with a false positive rate below 1% over a 24-hour period. The präsenzsensoren is deployed in hotel rooms (Hotelzimmer) for housekeeping coordination and energy management, in offices (Büros) for occupancy-based HVAC and lighting control, in healthcare facilities (Gesundheitseinrichtungen) for fall detection (Sturzerkennung) and patient monitoring, and in residential smart homes (Smart Homes) for automated lighting and climate control.

This guide provides a comprehensive overview of präsenzsensoren, covering the technology, the performance characteristics, the use cases, and the selection criteria for choosing the right sensor for a specific application. The guide is written in English to serve the international German-speaking audience that searches for präsenzsensoren but reads technical content in English.

Präsenzsensoren: The Technology

The technology behind modern präsenzsensoren is millimeter-wave (mmWave) radar.

Präsenzsensoren: mmWave Radar Basics

A mmWave radar präsenzsensoren emits a frequency-modulated continuous wave (FMCW) chirp that sweeps across a defined bandwidth (typically 7 GHz at 60 GHz) over a short period. The reflected signal from objects in the detection zone is mixed with a copy of the transmitted chirp, producing a beat signal whose frequency is proportional to the range of the target. By performing a Fast Fourier Transform (FFT) on the beat signal, the sensor can determine the range of every object in the detection zone with a resolution of approximately 2.1 cm.

The sensor then analyzes the phase of the beat signal across successive chirps to determine the velocity of the targets. A stationary person produces a beat signal with a slowly varying phase (due to the micro-motion of breathing), while a stationary chair produces a beat signal with a constant phase. By analyzing the phase variation (the micro-Doppler signature), the präsenzsensoren can distinguish a stationary human from a stationary object, enabling true presence detection.

Präsenzsensoren: Micro-Doppler and Breathing Detection

The micro-Doppler signature of human breathing is the key to detecting stationary occupants. The periodic motion of the chest wall during breathing (amplitude 5–20 mm, frequency 0.2–0.5 Hz) produces a Doppler modulation that is clearly detectable by a 60 GHz mmWave sensor with 7 GHz of bandwidth.

A well-designed präsenzsensoren uses signal processing techniques to extract the breathing signature from the radar return, distinguish it from background noise (HVAC airflow, building vibration, fan motion), and use it as a positive indicator of human presence. The result is a sensor that can reliably confirm the presence of a sleeping adult at 4 m with a true positive rate above 99% in controlled testing.

Präsenzsensoren: Why PIR Sensors Cannot Detect Stationary Occupants

A passive infrared (PIR) sensor, known in German as Bewegungssensor, cannot detect stationary occupants. The PIR sensor detects changes in infrared radiation across its field of view, and a stationary person does not produce a change in the radiation pattern. The PIR sensor therefore reports "no motion" within 10–30 minutes after the last movement, even if the room is occupied.

This is the fundamental limitation that makes a PIR sensor unsuitable for use as a präsenzsensoren in applications where the occupant may be stationary for extended periods.

Präsenzsensoren: Performance Metrics

The performance of a präsenzsensoren is characterized by several key metrics.

Präsenzsensoren: Stationary-Occupant True Positive Rate

The stationary-occupant true positive rate (TPR) is the percentage of time that a stationary human occupant is correctly reported as present. For a 60 GHz präsenzsensoren, the TPR is above 99% in controlled testing and above 95% in real-world deployment.

Präsenzsensoren: False Positive Rate

The false positive rate (FPR) is the percentage of time the sensor reports presence when the room is actually empty. For a well-designed präsenzsensoren, the FPR is below 1% over a 24-hour period.

Präsenzsensoren: Detection Range

The detection range of a 60 GHz präsenzsensoren is 6–8 m for stationary occupants and 8–12 m for moving occupants when ceiling-mounted at 2.5–3.0 m.

Präsenzsensoren: Detection Latency

The detection latency is the time between an occupant entering the detection zone and the sensor reporting the change. For a präsenzsensoren, the latency is typically 0.5–3 seconds.

Präsenzsensoren: Applications

The präsenzsensoren is deployed in a wide range of applications in German-speaking markets.

Präsenzsensoren: Hotel Rooms (Hotelzimmer)

Hotel rooms are the canonical application for the präsenzsensoren. A 60 GHz ceiling-mounted präsenzsensoren can reliably detect whether a guest is in the room throughout their stay, including when they are sleeping, and feeds the occupancy data to the building management system for housekeeping coordination and the HVAC system for energy management.

In the German, Austrian, and Swiss hotel markets (Accor, Maritim, Meininger, Mövenpick, Vienna House), the präsenzsensoren is increasingly being deployed in both new construction and renovation projects.

Präsenzsensoren: Offices (Büros)

Offices use the präsenzsensoren for per-room HVAC and lighting control, conference room availability detection, and space utilization analytics. The sensor's ability to detect stationary occupants is essential for office applications where workers may be at their desks for hours without significant movement.

Präsenzsensoren: Healthcare (Gesundheitseinrichtungen)

Healthcare facilities use the präsenzsensoren for fall detection, bed-exit alerting, and occupancy-based environmental control. The privacy profile of mmWave radar (no images, non-invasive) makes it suitable for deployment in private spaces.

Präsenzsensoren: Residential Smart Home (Smart Home)

Residential smart homes use the präsenzsensoren for occupancy-based lighting, HVAC control, and security monitoring. The most compelling use case for residential sensors is the prevention of the "light turned off while reading" problem that plagues PIR-based motion sensors.

Präsenzsensoren: German-Speaking Market Considerations

The German-speaking market for präsenzsensoren has some specific considerations.

Präsenzsensoren: Germany Market

The German market is the largest German-speaking market for präsenzsensoren, driven by the strong hospitality sector, the industrial and commercial real estate sectors, and the growing residential smart home market. The German market is served by both international vendors (PresenceSensor, Aqara, Honeywell, Siemens) and local distributors and integrators.

Präsenzsensoren: Austria and Switzerland Markets

The Austrian and Swiss markets are smaller but mature, with strong adoption in the hospitality sector (especially in the Alpine resort regions) and in the commercial real estate sector. The markets are served by both international vendors and local distributors.

Präsenzsensoren: KNX Integration

The German-speaking market has a strong tradition of KNX building automation, and many präsenzsensoren deployments in Germany, Austria, and Switzerland integrate with KNX. The KNX integration enables the präsenzsensoren to control lighting, HVAC, and shading based on the occupancy state.

Präsenzsensoren: Selection Criteria

Selecting the right präsenzsensoren for a specific application requires evaluating several criteria.

Präsenzsensoren: Technology

For indoor presence detection, 60 GHz mmWave radar is the default choice, providing reliable stationary-occupant detection with an excellent privacy profile.

Präsenzsensoren: Form Factor

For most applications, a ceiling-mounted sensor (70 mm diameter ceiling puck) is the right choice. For corridors and entryways, a wall-mounted sensor may be preferred.

Präsenzsensoren: Connectivity

The connectivity should match the existing infrastructure and the integration requirements. For hotel deployments, Zigbee is the most common. For office deployments, WiFi or PoE with BACnet is common. For residential deployments, Matter or Zigbee is the most common. For KNX-integrated deployments, a KNX interface is required.

Präsenzsensoren: Certifications

The präsenzsensoren should carry the required certifications for the target market. In the EU, CE marking is required, including compliance with the Radio Equipment Directive for wireless sensors.

Präsenzsensoren: Privacy and Compliance

The privacy and compliance considerations for a präsenzsensoren are similar to those in other markets.

In the EU, the GDPR and the German Bundesdatenschutzgesetz (BDSG) regulate the processing of personal data. A properly configured präsenzsensoren that processes all radar data on-device and only transmits anonymous occupancy events is generally outside the scope of personal data.

Präsenzsensoren: Final Recommendation

The präsenzsensoren is a mature, reliable technology that has become the default choice for presence detection in hotel rooms, offices, healthcare facilities, and residential smart homes across German-speaking markets. The 60 GHz mmWave radar is the default technology, providing reliable stationary-occupant detection, an excellent privacy profile, and a compact form factor.

For a procurement team or a consumer selecting a präsenzsensoren, the right approach is to start with a clear definition of the application requirements, then evaluate the available products from international vendors (PresenceSensor, Aqara, Honeywell, Siemens) and local distributors and integrators, then select a product that meets the requirements and is supported by a local supplier with the necessary certifications. With the right sensor, correctly installed and integrated, the präsenzsensoren can deliver a level of occupancy awareness that is impossible to achieve with PIR-based motion sensors, and can justify the higher unit cost through improved energy efficiency, better occupant experience, and more accurate occupancy data for downstream analytics.