Optex FLX-S-DT FLEX Series Motion Detector

We've deployed the Optex FLX-S-DT in dozens of residential retrofit and light commercial projects, and the flip-lens feature is genuinely useful in the field. It cuts the number of different PIR SKUs you need to carry, and it solves a real problem: many installers end up with the wrong detection pattern for a given room and either compromise coverage or order a new sensor. With the FLX-S-DT, you get one chance to get it right—flip the lens, and you're done. On a 10- or 15-home new-construction alarm build-out, that efficiency adds up. The 12 mA current draw is another quiet win; we've seen integrators oversize power supplies because they underestimate total load across motion sensors, door contacts, and auxiliary devices. This unit doesn't force that mistake. Where the FLX-S-DT has trade-offs: it's indoor-only (0–32°C operating range), so any outdoor or garage application requires a different part number. The narrow-pattern coverage, while adequate for entry hallways and bedrooms, tops out around 20–25 feet—don't spec it for wide-open warehouse floors or large commercial atriums. And because it's hardwired N.O./alarm relay output only, there's no metadata, no detection-class filtering, no integration with IP-based alarm panels or VMS platforms. It's a purpose-built sensor for traditional security control systems, which is exactly where it excels.

Technical Highlights:

• Flip-Lens Dual Pattern: Wide and narrow modes in a single sensor eliminate the need for field-selectable logic or dual units. The mechanical lens flip is durable and field-user-friendly; no calibration needed after switching.
• 12 mA Operating Current: Allows 10+ sensors on a single 24 V power supply without exceeding typical panel limits (120–150 mA per circuit). Reduces power-distribution complexity and PSU cost in multi-sensor layouts.
• IR Low-Light Capability: Passive infrared with temperature-compensated sensing; performs reliably in complete darkness and low-ambient conditions. Eliminates false negatives in unlit basements, stairwells, and nighttime entry points.
• Vertical Tilt Range (-5° to 20°): Allows mounting on either walls (shelf brackets) or ceilings without requiring angled mounting plates. Simplifies installation and accommodates off-standard ceiling heights and room geometries.
• Compact 130 mm Height: Fits standard 2×4 electrical boxes and blends into residential ceilings without crowding adjacent devices. Reduces visual clutter and integration hassle in finished spaces.

Deployment Considerations:

• Operating temperature ceiling is 32°C (90°F); attic, garage, and outdoor applications require different models. Test location temperature during site survey before ordering.
• Narrow-pattern detection tops out around 20–25 feet; do not spec for large open commercial spaces without supplementary motion coverage or manual testing during commissioning.
• Dual-pattern flexibility works best when the final lens orientation is locked after initial programming. Frequent in-field lens flipping can lead to confusion during troubleshooting; document the selected pattern in as-built drawings.
• Standard alarm panel integration assumes N.O. relay or hardwired output; wireless bridges and IP alarm platforms may require separate transmitter modules. Verify panel compatibility during pre-design phase.
• 12 mA draw is conservative under normal operation but peaks during alarm reporting; budget for 20–25 mA per sensor in worst-case current calculations to avoid nuisance resets.

The FLX-S-DT is the right call for residential integrators, local alarm dealers, and light commercial teams prioritizing cost efficiency, installation speed, and field flexibility. If you're building an entry-level system or refreshing a legacy alarm base with new sensors, this unit delivers reliable, low-maintenance performance. For larger or more specialized deployments, review the broader Optex catalog to identify models optimized for outdoor, wide-area, or networked installations.