Optex FLX-P-ST Indoor PIR Motion Detector Flip Lens
The Optex FLX-P-ST is an indoor passive infrared motion detector designed for residential and light commercial security installations. Its defining feature is the flip lens design, which allows field-selectable coverage patterns—wide or narrow—without requiring multiple SKUs or installation rework. The 12 mA operating current and dual mount options (wall or ceiling) make it a low-power, flexible choice for hardwired alarm systems and access control integration where power budget and mounting flexibility are constraints.
Key Features
- Flip Lens Design: Single lens switches between wide and narrow detection patterns. Eliminates the need to stock two SKUs and allows on-site coverage adjustment without device swap.
- Low Operating Current: 12 mA draw. Operates on standard 12V DC alarm circuits without dedicated power supply upgrade, reducing installation cost on retrofit jobs.
- Dual Mount Options: Wall or ceiling installation. Accommodates both retrofit and new-construction layouts; ceiling mount provides downward detection for hallways and rooms.
- IR Low-Light Capability: Passive infrared detection works in zero-light environments. No visible LED illumination required, preserving aesthetics in occupied spaces.
- Operating Temperature Range: 0–32°C (32–90°F). Suitable for climate-controlled interiors; not rated for outdoor or unheated garage/storage deployment.
- Compact Form Factor: 130 mm H × 62 mm W × 56 mm D (standard model). Fits standard electrical boxes and blends into residential trim without bulk.
- LED Status Indicator: Green LED signals warm-up and alarm states. Installer can verify functional detection during commissioning without opening the control panel.
- Vertical Tilt Range: −5° to 20° downward adjustment. Allows fine-tuning of coverage envelope on-site to avoid false triggers from ceiling fans, HVAC vents, or low-mounted moving objects.
The FLX-P-ST integrates with hardwired alarm control panels via dry contact closure on detection. ONVIF compliance is not applicable—this is a legacy zone sensor, not an IP camera—so compatibility depends on the alarm panel's input module type (standard supervised 4-20 mA or dry contact alarm loop). It pairs well with hybrid NVRs that support hardwired zone inputs alongside IP cameras, allowing a single recording timeline to correlate motion sensor events with video footage.
Deployment scenarios include residential hallways, stairwells, and bedrooms where motion-triggered recording or lighting control is desired without the footprint or cost of an IP camera. Light commercial applications—small retail stockrooms, office entries, utility closets—also fit the profile. The low current draw makes it ideal for installations where multiple sensors must share a single 12V DC power supply; typical alarm panels can support 8–16 sensors per loop depending on circuit design.
Total cost of ownership is favorable for small to medium installations. A single FLX-P-ST costs significantly less than an equivalent IP motion sensor with integrated video analytics, and it requires no network infrastructure. The trade-off is obvious: a hardwired PIR sensor generates a binary alarm signal, not metadata-rich event data. It cannot distinguish human motion from pet movement or verify the cause of an alarm without correlation to camera footage.
The device operates within the residential/light commercial band; it is not rated for outdoor, marine, or industrial environments. The 0–32°C temperature range excludes unheated storage spaces, outdoor shelters, and freezer applications. For those use cases, Optex manufactures ruggedized outdoor and cold-environment variants. Verify environmental conditions at the installation site before specifying.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The Optex FLX-P-ST occupies a specific niche: hardwired PIR motion detection for traditional alarm installations that are adding video recording capability. We've specified hundreds of these across retrofit jobs where the existing alarm panel already has zone loops in place and the customer wants motion-triggered camera recording without the expense of IP sensors on every hallway. The flip lens is the operational win here. On a typical residential or small office retrofit, you'll face coverage mismatches during site survey—a hallway that needs narrow focus, then a stairwell entry that needs wider pattern. With the FLX-P-ST, you order one SKU, install it, and field-flip the lens to match the actual surveillance need. That eliminates callbacks and reduces inventory overhead. The 12 mA draw is also significant if you're retrofitting an older alarm system with a power-limited 12V supply. Many legacy panels spec'd for 4–6 sensors become maxed out on a single loop; the FLX-P-ST's low current footprint lets you add motion sensors without power supply upgrades.
Technical Highlights:
- Flip Lens Dual Coverage: Wide pattern (~40 ft coverage in standard view) and narrow pattern (~20 ft focused beam) are field-switchable without device removal. Real outcome: one inventory line item instead of two, and zero rework time if initial coverage assumption changes.
- 12 mA Operating Current: Typical alarm panels source 12V at 200–500 mA per loop; a series of eight FLX-P-ST sensors draws only ~96 mA, leaving headroom for supervised wiring and relay coils. Matters when integrating into aging systems where power supply upgrade is cost-prohibitive.
- IR Passive Detection: PIR sensors in zero-light environments eliminate false triggers from reflective surfaces and headlights—a common problem with visible-light motion sensors. Trade-off: cannot distinguish human from large pet. Video correlation required for verification.
- −5° to 20° Vertical Tilt: Downward angle range lets you defeat false triggers from HVAC ducting, ceiling-mounted speakers, or fluorescent ballast hum without extensive re-mounting. Field adjustment on-site saves installation labor.
- Dual Mount (Wall/Ceiling): Most residential and light-commercial spaces have existing electrical boxes. This device fits standard boxes in either orientation, reducing the need for custom conduit runs or surface mounting.
Deployment Considerations:
- PIR sensors are blind to stationary heat sources and slow-moving thermal gradients. A person sitting motionless in a room for 30+ seconds may not trigger the alarm. If intrusion detection or continuous occupancy verification is the goal, pair with door/window contacts or redundant sensors on the same zone.
- Ceiling mounting works well for downward coverage (stairwells, hallways) but is poor for entry detection at door frames where an intruder passes horizontally. Wall-mount at 5–6 feet height for best cross-traffic sensitivity.
- The 0–32°C range is a hard floor. Unheated garages, outdoor eaves, and refrigerated areas will not trigger reliably below 32°F. Verify HVAC setpoints and seasonal temperature swings before installation.
- Hardwired alarm zone loops typically use 4-wire (power, ground, alarm, supervision) or 2-wire loops. Confirm your control panel's input module type before ordering; the FLX-P-ST is dry-contact output and requires a supervised loop on most modern panels.
- False-alarm liability in commercial installations is real. PIR sensors can trigger on reflected sunlight, rotating fans, or animals. Avoid placement in direct sunlight or near HVAC vents, and always correlate hardwired zone events to video timestamp to build a defensible incident record.
The FLX-P-ST is the right choice for integrators building hybrid alarm + IP video systems in residential and light commercial spaces where existing hardwired infrastructure is being retained and budget is tight. It's not suitable for outdoor, industrial, or high-temperature environments, and it doesn't replace IP video analytics for sophisticated threat detection. For customers wanting to leverage existing alarm panel investment while adding motion-triggered recording, this sensor is a cost-effective bridge technology. Explore the full Optex catalog for outdoor-rated and industrial variants.
