IR Illuminator Need Calculator

Plan safe, clear nighttime construction surveillance coverage. Adjust wavelength, beam spread, transmission, and safety margin. Export results for procurement, installation, and inspection reports quickly.

Calculated Results

Assumes inverse-square spreading, beam utilization, transmission losses, and a safety factor.

Inputs

Use camera datasheet targets or test footage to pick the irradiance.

Mount-to-scene distance.
Scene width you want lit.
Scene height you want lit.
Used if Auto-size beam is off.
Fits beam to max scene dimension.
Affects camera sensitivity, not geometry.
Typical cameras: 1–10 µW/cm² (varies widely).
Include any protective optics.
Polycarbonate/glass, mesh, etc.
0–1 clear air; higher for fog/dust.
Accounts for non-uniform beam.
Covers aging, misalignment, dirt.
Optical out / electrical in.
Optional for unit count sizing.
Construction tip: avoid aiming directly at reflective PPE or wet concrete; adjust angle to reduce bloom and hotspots.

Formula Used

The calculator estimates optical power required to achieve a target infrared irradiance on the scene, then scales for losses and coverage tiling.

How to Use This Calculator

  1. Measure the distance from the planned mount to the target area.
  2. Enter the coverage width and height you need illuminated.
  3. Choose a beam angle, or enable auto-sizing to match coverage.
  4. Set the desired irradiance using camera specs or field tests.
  5. Enter transmission losses and atmospheric attenuation for your site.
  6. Add a safety factor for misalignment, dirt, and LED aging.
  7. If you know a unit’s optical output, enter it for unit sizing.
  8. Click Calculate, then export CSV/PDF for procurement files.

Example Data Table

Distance (m) Coverage (W×H m) Beam (°) Irradiance (µW/cm²) Losses (Lens/Window) Safety Recommended Units
20 12 × 8 30 3.0 92% / 90% 1.30 Auto-calculated after you submit
35 18 × 10 40 4.5 90% / 88% 1.40 Auto-calculated after you submit
12 8 × 6 25 2.0 94% / 92% 1.25 Auto-calculated after you submit

Site Survey and Risk Zones

Start by mapping camera sightlines, entry points, and high value storage. Record mounting heights, obstructions, and reflective surfaces like wet concrete or metal cladding. Note nearby cranes, light poles, and temporary fences that could block or shadow the beam. Use distance and coverage dimensions from the survey so the illuminator footprint matches the monitored zone without wasting spill light.

Target Exposure and Image Quality

Choose a target irradiance based on acceptable motion blur and noise. Higher shutter speed and lower gain improve identification, but demand more infrared power. Confirm whether the camera switches to monochrome and disables its internal emitter. Validate by night testing: capture a short clip, then adjust the irradiance input until faces, badges, or vehicle plates are readable at the required distance.

Losses, Contamination, and Weather

Construction sites add dust, vibration, and temporary barriers. Model lens and window transmission to represent housings, domes, or protective covers. Add atmospheric attenuation for fog or heavy dust, and apply a safety factor for LED aging, dirty optics, and aiming error during repositioning or scaffold movement. Plan routine cleaning intervals and verify fasteners so alignment does not drift between inspections.

Beam Geometry and Unit Placement

Beam angle sets beam diameter at the target and drives how many fixtures are needed to tile the rectangle. Narrow beams increase range but require more units for wide areas. For corridors, orient beams along the long axis to reduce overlap. Auto sizing is useful when coverage changes frequently; otherwise, pick a beam that slightly exceeds the largest dimension to reduce seam lines.

Power, Heat, and Procurement Planning

Convert required optical power to electrical load using emitter efficiency. Check driver and cable losses, then confirm thermal limits, especially in sealed enclosures. Ensure power supplies meet ingress and surge requirements for temporary power. Use the unit optical rating field to estimate quantity and per unit output, supporting procurement, generator sizing, and preventative maintenance schedules. Document settings in commissioning notes for future audits.

FAQs

1. What irradiance value should I start with?

Start with 2 to 5 µW/cm² for general detection at moderate distances. Increase for identification tasks, fast shutter speeds, or dark lenses. Use night test footage to tune the value until details meet your security objective.

2. Should I choose 850 nm or 940 nm?

850 nm typically delivers longer range because many sensors are more sensitive there, but it can show a faint red glow. 940 nm is less visible to people, yet may require more power for the same image brightness.

3. Why does the calculator ask for beam utilization?

Real beams are not perfectly uniform. Utilization estimates how much of the beam effectively contributes to your usable exposure after hotspots and falloff. Lower utilization increases required optical power and can reduce the risk of dark edges.

4. How do I estimate atmospheric attenuation?

Use 0 to 1 dB/km for clear air, 1 to 3 dB/km for light haze or dust, and higher for fog or heavy dust. If conditions change often, raise the safety factor and consider adjustable, higher output fixtures.

5. How is the recommended unit count determined?

The tool sizes units two ways: coverage tiling based on beam diameter, and intensity sizing based on total optical power versus per unit rating. It recommends the larger value, helping avoid gaps and underexposure.

6. Can I use this for temporary site power planning?

Yes. The calculator outputs estimated electrical load from optical power and efficiency. Add driver losses, cable voltage drop, and generator derating. For sealed housings, verify heat dissipation and follow manufacturer limits.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.