Warehouse lighting sensors: PIR vs microwave vs daylight
Choosing the right sensor for a warehouse or distribution centre depends on mounting height, racking, daylight and how empty aisles should behave. This guide compares PIR, microwave and daylight sensors, and how occupancy, absence, aisle dimming, DALI and wireless control fit together.
The short answer
- PIR detects moving heat and needs line of sight. Use it on open floors at moderate height.
- Microwave (HF) detects movement through thin materials and suits higher mounting and racking. Limit the range so the next aisle does not trigger.
- Daylight dims or switches under rooflights so you do not over-light when the sun is up.
- On PS-UFO-MAX, plug-in PIR + daylight or microwave + daylight sensors fit without rewiring. With a sensor fitted, the fitting is rated down to -35°C.
PIR sensors
A PIR sensor responds to moving infrared (body heat). It needs a clear view of the aisle or floor. It is a good fit for open production halls and loading areas where people walk in the sensor’s field of view. For PS-UFO-MAX, the plug-in PIR + daylight sensor is recommended at 10 m mounting height (12 m maximum).
Microwave sensors
A microwave (typically 5.8 GHz) sensor detects movement and can see through thin materials. That helps at higher mounting heights and between racking, but loose packaging, fans or the next aisle can cause false triggers if the range is too high. For PS-UFO-MAX, the plug-in microwave + daylight sensor is recommended at 12 m (15 m maximum). At 12 m the detection radius is at least 4 m. PS-BATTEN has a built-in 5.8 GHz microwave sensor for lower mounting (sensor max. 4 m).
Daylight sensors and harvesting
Daylight sensors measure light under rooflights or near doors and dim or switch the fittings so you only add what is needed. They work best as zones linked to the daylight openings, not as one threshold for a whole hall. Combine them with occupancy so empty, bright aisles do not stay at full output.
Comparison
| Point | PIR | Microwave | Daylight |
|---|---|---|---|
| Detects | Moving heat | Movement (HF) | Ambient light level |
| Line of sight | Required | Not always | Views the lit surface or opening |
| Through thin materials | No | Yes | n/a |
| PS-UFO-MAX height | 10 m rec., 12 m max | 12 m rec., 15 m max | With either plug-in |
| Typical false triggers | Heat sources in view | Fans, packaging, next aisle | Wrong threshold or zone |
Occupancy vs absence, aisle dimming and linking
Occupancy detection turns light up when someone arrives. Absence detection usually needs a manual on, then dims or switches off when the space empties. In racking aisles, a stand-by dim level (corridor function) keeps a low light for safety and cameras between picks, then returns to full output when a truck enters. That is not emergency lighting.
Link daylight zones under rooflights so those fittings dim first. Keep forklift aisles, picking and despatch on separate control groups so one busy aisle does not light the whole block.
DALI vs wireless
DALI addressable drivers give fine control over wired groups and suit new builds or rewires. 0-10 V with 2- or 3-step dimming is common on plug-in high bay sensors. Wireless grouping links sensors without new control cabling and suits many LED upgrades. PS-UFO-MAX is available with DALI; plug-in sensors support 0-10 V step dimming and wireless grouping. For a full warehouse network, see Polaris Mesh.
Cold stores and freezers
With a plug-in sensor fitted, PS-UFO-MAX is rated down to -35°C. For cold-store fitting choice and hygiene, use the free cold store lighting guide.
Which Polaris fitting has which sensor
- PS-UFO-MAX: optional plug-in PIR + daylight or microwave + daylight; DALI and emergency options available.
- PS-BATTEN: built-in 5.8 GHz microwave; 3-hour emergency version (60-S EM).
- PS-CURVE: optional motion and daylight sensors (sensor type not specified); 1-10 V or DALI dimming.
Also see the LED high bay lights buyer’s guide and warehouse emergency lighting.
Frequently asked questions
When should I use PIR and when microwave?
PIR needs a clear view of moving heat and suits lower open floors. Microwave detects movement through thin materials and suits higher mounting and racking. On PS-UFO-MAX, PIR is recommended up to 10 m (12 m max) and microwave up to 12 m (15 m max).
What mounting heights do PS-UFO-MAX sensors support?
Plug-in PIR + daylight: 10 m recommended, 12 m maximum. Plug-in microwave + daylight: 12 m recommended, 15 m maximum. At 12 m the microwave detection radius is at least 4 m.
Is stand-by dimming the same as emergency lighting?
No. Stand-by (corridor) dimming saves energy when an aisle is empty. Emergency lighting is a separate legal duty under the Regulatory Reform (Fire Safety) Order 2005. See our warehouse emergency lighting guide.
What is occupancy vs absence detection?
Occupancy detection switches or raises light when someone arrives. Absence detection usually needs a manual on and then switches off or dims when the space empties. Warehouses often use occupancy with a stand-by dim level in aisles.
Do you offer DALI and wireless control?
Yes. PS-UFO-MAX is available with DALI. Plug-in sensors support 0-10 V with 2- or 3-step dimming and wireless grouping. For networked warehouse control see Polaris Mesh.