What is a sensor light? How it works, types, and how to choose.
Sensor lights switch themselves on when people or vehicles move — and off when they leave. Here is what is inside, which types exist, and what to check before buying, from a KC-certified manufacturer that designs the sensor modules themselves.
How a sensor light works
Sensor light = detection sensor + control circuit + LED module. The sensor and control logic decide the performance.
① Motion detection
A 5.8GHz doppler sensor (frequency shift of reflected waves) or PIR sensor (body-heat infrared) picks up movement of people or vehicles.
② Day/night decision
A built-in illuminance sensor measures ambient light so the fixture only reacts in the dark, using a tunable LUX threshold.
③ Switching & dimming
The control circuit lights the LED instantly, then returns to full-off or a low-brightness standby (0–100% dimming) after the hold time.
④ (Advanced) group control
Fixtures talk to each other over BLE Mesh: one detection can light neighboring fixtures, or fixtures ahead of a moving vehicle.
Types of sensor luminaires
Ceiling-mount (entrance · corridor · stairs)
The most common form. A compact module (e.g. 18×18 mm) embeds into the fixture; widely used in apartment entrances and shared corridors.
Parking-garage lights
Fixtures light sequentially along the direction of travel. AI group control learns traffic patterns and eliminates unnecessary switching.
High-bay factory & logistics lights
High mounting heights require long-range doppler detection; BLE Mesh links fixtures into zone-level control.
Residential common areas
Stairs, corridors, underground parking. Low standby power (<0.3 W) and automatic day/night switching drive the savings.
Pre-purchase checklist
Sensing principle
Hidden sensor behind a cover → doppler. Short range at low cost → PIR.
Range & angle
Check real specs at your mounting height (e.g. 0.3–7 m radius, 15 m linear, 120°).
Illuminance sensor
Required for day/night switching; check if the LUX threshold is tunable.
Dimming behavior
Full-off vs low-brightness standby (e.g. 10 steps, PWM) — affects safety and comfort.
Standby power
The fixture waits 24/7 — aim for under 0.5 W (BIO sensors: <0.3 W).
Certification
Radio-emitting doppler sensors require KC certification in Korea. Verify the certificate number.
FAQ
Q. How much energy does a sensor light save?
Compared with always-on lighting the savings depend on traffic and hold-time settings, so measure on site. Low standby power (<0.3 W) products maximize the benefit.
Q. Can the sensor be invisible from outside the fixture?
Yes with 5.8GHz doppler — the waves pass through plastic and glass covers. PIR lenses must stay exposed.
Q. Can detection range or hold time be changed after installation?
Depends on the product. BIO sensors support field tuning of range, hold time, dimming and LUX threshold via IR remote or an Android app with a Type-C dongle.
Q. We build luminaires — can we source just the sensor module?
Yes. BIO Electronics supplies sensor modules standalone and offers OEM/ODM development including firmware and antenna tuning. Samples available.
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