Optex FTN-ST Wired Outdoor Compact PIR: Short-Range Curtain Detection with Pet Immunity
Standard motion sensors cast a wide detection cone that picks up everything within a broad arc. For protecting a specific entry point like a front door, window, or balcony railing, that broad coverage creates more problems than it solves: pedestrians on the pavement trigger alerts, passing vehicles set off false alarms, and the sensor becomes something you learn to ignore rather than trust. The Optex FTN-ST takes a fundamentally different approach with short-range curtain detection that creates a narrow, vertical detection plane directly in front of the protected opening. Anything that passes through that invisible curtain triggers the alarm. Everything outside it gets ignored.
Detection range is switchable between 2 metres and 5 metres using interchangeable lenses built into the unit, letting you match the coverage precisely to the depth of a doorway recess, window ledge, or balcony. A shallow window alcove gets the 2-metre setting. A wider entrance or patio door gets the 5-metre lens. One sensor model covers both scenarios without buying separate units for different positions around the property.
False alarm reduction is where the FTN-ST separates itself from generic outdoor PIRs. The unit uses Optex's Super Multi Dimension Analysis (SMDA) logic, which digitally processes the infrared waveform of every detected movement before deciding whether to trigger. Rather than reacting to any temperature change in the detection zone, the sensor analyses the shape, speed, and thermal signature of what moved. Reflections from direct sunlight, air currents from HVAC units, and vegetation swaying in the wind are all recognised and filtered out. Optex claims this processing makes the sensor's environmental response 24 times more effective than conventional single-element PIR designs.
Pet immunity works through a dual-beam architecture. The sensor generates separate upper and lower passive infrared beams, and both must register a presence simultaneously to trigger an alarm. A cat walking along a wall, a dog crossing beneath the sensor, a bird landing on a windowsill, or a fox passing through the garden will only break one beam at a time due to their smaller body profile. A human walking upright breaks both beams, triggering the alert. This physical filtering method is inherently more reliable than software-based pet immunity that relies on signal amplitude alone.
The body is remarkably compact at just 100 grams, slim enough to sit inside a window or door recess without protruding. The built-in mounting bracket rotates 190°, giving you fine control over the sensor's aim during installation without needing separate adjustable hardware. Recommended mounting height is 0.8 to 1.2 metres, which places the detection curtain across the body height of an adult entering through a door or climbing through a window.
As a hardwired sensor, the FTN-ST connects to any standard alarm panel via its selectable normally closed or normally open relay output. A separate tamper output opens the circuit if the cover is removed, alerting the panel to physical interference with the sensor. Current draw peaks at just 17 mA on 12 VDC, so the unit adds negligible load to an alarm panel's power budget even when running alongside multiple other sensors on the same zone bus.
Double conductive shielding inside the housing protects the sensor electronics from external electromagnetic interference, which matters in installations near electrical switchgear, air conditioning compressors, or other sources of RF noise that can cause phantom triggers on unshielded sensors.
The unit carries an IP55 weather rating and operates from -20°C to +60°C, suitable for permanent outdoor installation in all South African climate zones. Detectable movement speed ranges from 0.3 to 1.5 m/s with a thermal sensitivity of 2.0°C at 0.6 m/s, calibrated to reliably detect a human walking at normal pace while filtering out slower environmental changes like gradual temperature shifts or creeping shadows.
Specifications
| Model |
FTN-ST |
| Series |
Optex FTN |
| Detection Method |
Passive infrared (dual beam) |
| Detection Coverage |
2 m or 5 m (switchable lens) |
| Detection Type |
Short-range curtain |
| Detectable Speed |
0.3 to 1.5 m/s |
| Sensitivity |
2.0°C at 0.6 m/s |
| Pet Immunity |
Yes (dual upper/lower beam) |
| Processing |
SMDA (Super Multi Dimension Analysis) |
| Shielding |
Double conductive |
| Power Input |
9.5 to 18 VDC |
| Current Draw |
17 mA max (at 12 VDC) |
| Alarm Output |
N.C. / N.O. selectable, 28 VDC 0.1 A max |
| Tamper Output |
N.C., 28 VDC 0.1 A max (opens on cover removal) |
| Alarm Period |
2.0 ± 1.0 sec |
| Warm-Up |
Approx. 60 sec (LED blinks) |
| LED Indicator |
Light/blink during warm-up and alarm |
| Mounting Height |
0.8 to 1.2 m |
| Bracket Rotation |
190° |
| Installation |
Outdoor |
| Protection |
IP55 |
| Operating Temp |
-20°C to +60°C |
| Humidity |
95% max |
| Weight |
100 g |
| Accessories |
2 × screws (3 × 20 mm) |
Precision perimeter detection for doors, windows, and balconies without the false alarms that make homeowners distrust their own security system. Buy the Optex FTN-ST outdoor PIR sensor online at NeonSales, delivered across South Africa.
