The main types of occupancy sensors used in lighting control include passive infrared (PIR), ultrasonic, radar-based and dual-technology sensors. Each uses a different detection method, making it important to match the sensor to the room, occupant activity and intended lighting behaviour.
A sensor suitable for people walking through a corridor may perform differently in a meeting room where occupants remain seated. Choosing the right technology helps reduce unwanted switching and improves the experience of using automatic lighting.
This guide explains the main sensor technologies, installation options and selection considerations for building projects in Saudi Arabia.
An occupancy sensor provides information that a lighting system uses to determine whether a space is occupied. Depending on the equipment and configuration, that information can trigger lights to turn on, remain on, dim or switch off after a period without detected activity.
Many occupancy sensors rely on movement. The term does not automatically mean that a device can detect a completely stationary person.
For a closer explanation of the terminology, read our guide to occupancy sensors vs motion sensors.
Passive infrared sensors, commonly called PIR sensors, detect changes in infrared energy as people move through their coverage zones.
They require a clear view of the activity being monitored. Partitions, furniture and other obstructions can create gaps in coverage.
PIR can be suitable for circulation areas, storage rooms and enclosed spaces with regular movement. Suitability depends on the particular model and its installation.
For offices, check the manufacturer’s minor-motion coverage. A sensor’s maximum walking-detection range does not establish how reliably it will detect someone working at a desk.
Ultrasonic sensors transmit high-frequency sound waves and detect changes in the reflected signals caused by movement.
They can detect smaller movements and provide coverage around some obstacles. This makes them an option to evaluate for partitioned rooms and spaces where occupants move less frequently.
However, airflow and other disturbances can cause unwanted detection. Placement and sensitivity adjustments are important.
Potential applications include partitioned offices and washrooms with cubicles, subject to the manufacturer’s recommendations.
Check coverage near doorways so activity outside the intended room does not unnecessarily keep its lights on.
Radar-based sensors use radio signals to detect movement. Products may use different frequencies and processing methods, so performance varies considerably.
Some models are designed for movement detection, while others offer documented sensitivity to very small movements. Always check the specific product rather than assuming that every radar sensor provides the same presence-detection capability.
Review the detection zone, installation materials and sensitivity settings. Depending on the technology and surrounding materials, detection may extend beyond the intended area.
Test the sensor in the finished room, including activity in adjacent spaces.
Dual-technology sensors combine two detection methods, commonly PIR and ultrasonic.
The technologies work together to support occupancy detection, but the control logic varies. Some products use different conditions to activate lighting and to maintain the occupied state.
These sensors are worth evaluating where one sensing method struggles with room layout or occupant activity.
Ask how the device responds when only one technology detects movement. The answer affects both occupant comfort and unwanted switching.
| Technology | Detection method | Main selection consideration |
|---|---|---|
| PIR | Changes in infrared energy associated with movement | Clear view and suitable movement coverage |
| Ultrasonic | Changes in reflected sound waves | Sensitivity to small movements and environmental disturbances |
| Radar-based | Radio signals used to detect movement | Model-specific detection performance and zone boundaries |
| Dual technology | Two sensing methods working together | How the technologies interact to control lighting |
No technology is the best choice for every room. Select against the application and verify performance during commissioning.
“PIR” describes a sensing technology. “Wireless” describes communication. A sensor can therefore be both PIR and wireless.
Also, wireless communication does not necessarily mean battery-powered operation. Confirm the power supply separately.
For retrofit projects, evaluate communication coverage, controller compatibility and maintenance access. Alrouf’s RF Series wireless lighting control system provides a starting point for discussing compatible sensor and controller options.
For the wider relationship between sensors, controllers and lighting equipment, explore our smart lighting system guide.
Occupancy and vacancy describe lighting behaviour rather than the physical detection method.
In typical occupancy operation, detection can automatically turn lights on, with automatic switching off after a configured delay. Vacancy operation requires manual activation and provides automatic switching off.
Some devices offer selectable modes. Confirm the available functions and how manual controls interact with automation.
Where manual operation is required, review compatible options such as Alrouf’s wireless kinetic switches.
Alrouf’s 2026 Smart Lighting Solutions catalogue lists these models in its RF Series sensor section:
| Model | Listed sensor type | Catalogue details |
|---|---|---|
| H2 | PIR Sensor | Recessed installation, RF 433 MHz communication and an adjustable sensitivity range stated as 0–8 metres |
| H4 | Battery-Powered PIR Sensor | External mounting, RF 433 MHz communication, and light-level, sensitivity and time settings |
| H3 | Human Body Sensor | Described as radar-based, with adjustable sensitivity and time delay |
The technologies discussed elsewhere in this guide explain general market options. For an Alrouf specification, confirm the selected model’s availability, operating characteristics and compatible controller.
Before requesting a quotation, prepare:
Include commissioning and documentation in the procurement discussion. Our guide to choosing a commercial lighting control supplier in Saudi Arabia explains the questions to raise before placing an order.
Choose a model with documented performance for the expected activity, particularly seated work. Consider partitions, ceiling height and minor-motion coverage.
Sometimes, but room size alone is insufficient. Layout, obstructions, mounting position and the manufacturer’s coverage diagram determine whether additional sensors are needed.
No. Some include a light-level threshold or photocell; others do not. Daylight-responsive switching and continuous daylight dimming are also different functions.
Yes. Coverage, sensitivity, timing and manual-control behaviour should be tested in the finished space.
Explore Alrouf’s Smart Lighting Solutions for your next building project. Share your layouts and intended lighting sequence to discuss sensor and controller options suited to the application.
