Knightsbridge Recess Mount 5.8GHz HF Motion Sensor - White

The Knightsbridge OSHFREC is a recess-mount 5.8GHz high-frequency motion sensor designed to automate lighting in corridors, stairwells, storage rooms and other spaces where hands-free control improves convenience and energy efficiency. The sensor sits flush in the ceiling behind a 90mm white polycarbonate bezel, requiring a 62mm diameter cut-out and 35mm recess depth above the ceiling surface.

The 5.8GHz microwave detection technology provides 360° coverage across a 3m diameter zone when installed at a standard 3m ceiling height, detecting motion through non-metallic materials such as plasterboard and lightweight partitions. This makes it suitable for triggering lighting in rooms where occupants may be partially screened from the sensor. The unit supports loads up to 1000W incandescent or 100W LED on 230V mains, with adjustable time delay (30 seconds to 30 minutes), lux threshold (5-1000 lux) and sensitivity range (1-3m).

Four operational modes are selectable via onboard controls: Auto (sensor activates light when motion is detected and ambient light falls below the set lux threshold), Short Pulse (briefly triggers light for confirmation without sustained illumination), Test (15-second intervals for installation verification), and Manual Override (forces light on regardless of motion or ambient light). The IP20 rating limits use to internal dry spaces only. The separate driver module connects to mains via a short fly-lead from the sensor head.

Product Specification Sheet

Product Manual

What ceiling depth is required for installation?

The sensor requires a 62mm diameter cut-out and a minimum 35mm recess depth above the ceiling surface to accommodate the driver module and wiring. The sensor face projects just 2mm below the finished ceiling once installed.

What's the difference between HF and PIR sensors?

High-frequency (microwave) sensors like this 5.8GHz unit detect motion through non-metallic materials such as plasterboard, whereas passive infrared (PIR) sensors require direct line-of-sight to the moving object. HF sensors are less prone to false triggers from temperature changes but may detect motion beyond walls in adjacent rooms if not calibrated correctly.

Can the sensitivity and timer be adjusted?

Yes. The onboard controls allow adjustment of detection range (1-3m), time delay before the light switches off (30 seconds to 30 minutes), and lux threshold (5-1000 lux, controlling the ambient light level below which the sensor activates).

Is it suitable for LED lighting?

Yes, the sensor supports LED loads up to 100W or incandescent loads up to 1000W. For larger installations or multiple zones, pair the sensor with a contactor or relay to avoid exceeding the rated load.