Studio Matrx Monthly · Volume 1 · Issue 2 · July 2026
Amogh N P
 In loving memory of Amogh N P — Architect · Designer · Visionary 
Perimeter & security lighting

Motion Light Placement Tool

One PIR light only covers as far as it reaches. Enter the length of the run or approach you want lit, each fixture’s detection reach and the overlap you want between neighbours, and this tool spaces the motion lights so there are no dark gaps. Planning figures; runs in your browser.

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Motion lights along the run
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Effective / light
0.0 m
Mounting height
Covering a 40 m run with lights that reach 12 m each and 15% overlap needs about 4 fixtures, spaced roughly 10.2 m apart.
Aim & setup pointers
  • • Aim the PIR across the path of travel, not head-on — sensors trigger far better on movement crossing the beam than on someone walking straight at it.
  • • Mount ~2.5–3 m: above tamper reach, with a good detection fan.
  • • Keep it off heat sources, AC units, reflective surfaces and the road — those cause false triggers and neighbour nuisance.
  • • Set the lux threshold so it fires only after dark, with a short-ish on-time.
  • • Pair motion lights with a steady low background light and a camera, so movement is both lit and recorded.

Indicative planning estimate only — real PIR reach, spread and false-trigger behaviour vary by model, mounting angle and site. Verify reach and aim with a night walk-test, and confirm figures against the product datasheet before you fix positions. Where a sensor watches a public road or a neighbour’s land, mind privacy (DPDP) — angle it to your own approach.