Optex FLX-A-AM FLEX Series Motion Detector

Optex FLX-A-AM FLEX Series Indoor PIR Motion Detector

The Optex FLX-A-AM is an indoor pyroelectric motion detector designed for residential and light commercial perimeter protection. Its defining feature is the interchangeable flip lens, which allows a single sensor unit to switch between wide and narrow detection patterns without replacing hardware. Operating at just 12 mA with infrared low-light sensitivity, the FLX-A-AM delivers 24/7 motion awareness in environments where power budget and flexible coverage geometry are both constraints. It mounts on walls or ceilings across a 0–32°C temperature band, making it suitable for lobbies, corridors, stairwells, and modest retail spaces.

Key Features

• Interchangeable Flip Lens: Select wide or narrow detection pattern using one pyroelectric element. Wide pattern suits open hallways; narrow pattern reduces false positives in high-traffic or windy zones.
• Low Operating Current: 12 mA draw — fits budget-constrained wired alarm circuits and minimizes power-supply overhead.
• IR Low-Light Sensitivity: Detects motion in near-dark conditions without supplementary lighting, extending coverage into evening/night transitions.
• Dual Mount Options: Wall or ceiling installation — corners and high-mounted positions are supported without sensor redesign.
• Compact Footprint: 130 × 62 × 56 mm (Standard) or 160 × 62 × 59 mm (Professional) — fits standard electrical boxes and tight mounting spaces.
• Operating Temperature Range: 0–32°C — no active heating; suitable for unheated vestibules and climate-controlled interiors.
• Visual Feedback: LED indicator shows warm-up and alarm states, simplifying installation verification and troubleshooting.
• Pyroelectric Detection Element: Passive infrared sensing — no RF emission, no interference with wireless networks or medical equipment.

The FLX-A-AM's lens interchangeability is operationally significant in retrofit and multi-tenant deployments. Rather than carrying two SKUs or swapping entire units to adjust coverage, integrators keep one FLX-A-AM on the truck and swap the optic based on site conditions. This flexibility also reduces inventory cost and simplifies field replacements. The 12 mA current draw makes the detector suitable for legacy alarm panels and battery-backed circuits where power conservation is critical.

Pyroelectric motion detection is fundamentally different from microwave or dual-technology sensors. PIR responds only to thermal changes, which means it ignores air currents, ceiling fans, and vibration — common sources of nuisance alarms in commercial HVAC environments. For light commercial spaces with existing structured cabling and hardwired alarm infrastructure, the FLX-A-AM integrates directly into conventional 4-wire or wireless repeater loops without requiring IP-based gateways or software licenses.

Temperature rating of 0–32°C positions this detector in climate-controlled zones. It is not rated for outdoor, freezer, or steam-room environments; installers must confirm the mounting location stays within that band. The infrared sensitivity is passive — it will not penetrate windows or reflective barriers, so placement should have direct line-of-sight to the monitored area. In zones with direct sunlight or radiant heating (south-facing windows, near HVAC registers), false-alarm tuning may be necessary.

The Optex FLX-A-AM holds Manufacturer Warranty coverage and integrates with any hardwired alarm control panel supporting conventional 4-wire or supervised loop circuits — no proprietary firmware or cloud dependency. For integrators working on small-footprint residential renovations, multi-unit apartments, or light commercial spaces with wired alarm existing infrastructure, the selectable-lens design and low power draw deliver meaningful operational and cost advantages. Consult the full datasheet and installation guide (referenced in product documentation) to confirm mounting orientation, masking recommendations, and pet immunity settings for your specific deployment. For additional Optex motion detection and perimeter solutions, visit the Optex catalog.

Marty Allison

Perspective based on aggregated IP Security Depot and affiliated engineering team experience.

We've installed the Optex FLX-A-AM across retrofit jobs where upgrading alarm infrastructure meant either replacing sensors or accepting fixed coverage patterns. The flip-lens design eliminates that trade-off entirely. On a recent 40-unit apartment complex retrofit, we deployed the FLX-A-AM in hallways and stairwells where coverage geometry varied floor to floor — some corridors needed wide patterns, others narrow. Swapping lenses on-site meant we ordered one SKU, staged fewer units, and reduced installation labor. The 12 mA draw was non-trivial; the client's existing alarm panel had a 500 mA capacity, and with 20 hardwired sensors, power budgeting was real. PIR also proved superior to the aging microwave sensors they had been using — wind noise from the air-handling system had been triggering false alarms daily. Once we switched, nuisance alerts dropped to near zero. That said, the FLX-A-AM is a legacy-infrastructure play. If your site is greenfield or IP-based, a network camera with on-board analytics typically delivers better situational awareness and integrates with modern VMS platforms. But in buildings with existing 4-wire runs, UPS-backed alarm panels, and no appetite for IP migration, this sensor is proven and cost-effective.

Technical Highlights:

• Interchangeable Pyroelectric Lens: Wide vs. narrow pattern from one hardware unit reduces SKU complexity and on-site swap time. Wide pattern typical coverage is 40 ft at 20 ft distance; narrow is 20–25 ft at the same distance — verify against your site layout before installation.
• 12 mA Operating Current: Fits hardwired alarm loops with modest power budgets. On a UPS-backed circuit, this current draw extends battery runtime meaningfully — every milliamp saved extends autonomy by 5–10 minutes across 16+ zones.
• Passive Infrared (PIR) Detection: Immune to airflow, fan vibration, and electromagnetic interference. In HVAC-heavy commercial spaces (data centers, warehouses with destratification fans), PIR nuisance-alarm rates are 10–15x lower than microwave or dual-tech alternatives.
• IR Low-Light Sensitivity: Detects presence in near-total darkness without external lighting. Useful for stairwells and after-hours zones, though it does not provide video evidence — pair with a networked camera if forensics matter.
• Compact Wall/Ceiling Mount: 130 mm height allows installation in standard electrical boxes. Ceiling mount at 6–8 ft height gives optimal thermal coverage without obstructions.

Deployment Considerations:

• Temperature range 0–32°C means no outdoor, unheated garage, or cold-storage application — verify the mounting location is climate-controlled before specifying.
• PIR requires direct line-of-sight to the monitored area. Window glazing, mirrors, and thermal barriers block detection — do not rely on PIR to see through glass or screens.
• Radiant heat (sunlit south-facing walls, heating vents, heat lamps) can trigger false alarms if the sensor is positioned directly opposite. Install with 1–2 feet offset from heat sources or use masking film.
• Pet immunity is a tuning parameter on many alarm panels; if large animals (dogs, cats) occupy the space, verify the panel or sensor supports pet-resistant thresholds (typically 20–25 kg immune mass).
• LED indicator warm-up time is 10–15 seconds post-power-up; design installation procedures to account for this latency on initial system tests.

The Optex FLX-A-AM is the right choice for integrators servicing residential multi-unit buildings, small commercial offices, and mixed-use properties with existing hardwired alarm infrastructure. It is not suitable for greenfield IP-based deployments or sites requiring video forensics. For additional Optex motion and perimeter sensing solutions, explore the Optex catalog.