IndiGo LightMeter: Portable spectrometer for measuring LEDs and PAR

The IndiGo Light Meter is a specialized version of our portable spectrometer, specifically configured and calibrated for the advanced characterization of light sources and the measurement of horticultural PAR flux. Covering the spectral range from 400 nm to 750 nm, it features a front-mounted cosine corrector that ensures optimal light collection at incident angles up to 70°. Factory-calibrated with its intensity correction directly stored in its internal memory, it communicates via Bluetooth Low Energy (BLE) with the dedicated SpectroLight app on Android smartphones for instant on-the-go measurements.

Integrated Input Optics & In-Memory Calibration

Designed for immediate field use without the need to assemble accessories or perform complex optical adjustments:

• Integrated cosine corrector: Positioned directly at the front of the device, it ensures an accurate angular response according to Lambert’s law up to 70°, preventing orientation errors when measuring diffuse light sources or light under a canopy of vegetation.
• Autonomous intensity correction: The intensity calibration table is preloaded directly into the IndiGo’s microcontroller. No reliance on an external file: the spectral profile returned to the application is immediately corrected for variations in sensor sensitivity and the optical bench.
• Mechanical tripod mount (optional): Standard Kodak-type thread (1/4″-20) available upon request to securely position the device during illuminance mapping or extended monitoring.

Measurement & Characterization of Light Sources (LEDs)

Based on a spectrum corrected for relative intensity in the 400–750 nm band, the IndiGo Light Meter provides access to all standardized photometric and colorimetric parameters:

• Reconstruction of the actual emission profile: Accurate visualization of emission peaks (blue LEDs, yellow/red phosphors, RGBW multichips, discharge lamps).
• Color and chromaticity metrology: Instantaneous calculation of chromaticity coordinates in the CIE 1931 (x, y) and CIE 1976 (u’, v’) color spaces.
• Correlated Color Temperature (CCT): Exact determination of CCT in Kelvin (K) to evaluate the warmth or neutrality of white lighting.
• Color Rendering (IRC / CRI): Comprehensive evaluation of the general color rendering index (R_a) and specific indices (R_1 through R_14), including the crucial R_9 (saturated red), which is essential for precision, medical, or museum lighting.
• Excitation Purity & Dominant Wavelength: Precise determination of the wavelength perceived by the human eye for monochromatic light sources.

Measurement of Photosynthetically Active Radiation (PAR) in Horticulture

For greenhouse vegetable production, vertical farms, and agricultural research, the 400–750 nm range allows for the full utilization of the spectrum useful to plants:

• Photosynthetically Active Photon Flux (PPFD): Conversion of the corrected spectral profile into photon flux density over the standard PAR range (400–700 nm) to quantify the light directly absorbable by chlorophylls a and b.
• Far-Red Integration (ePAR / 700–750 nm): Inclusion of the extended wavelength band up to 750 nm, which is essential for evaluating the Emerson effect and overall photosynthesis.
• Red/Far-Red Ratio (R/FR): Real-time calculation of the ratio between the red band (660 nm) and the far-red band (730 nm), a fundamental parameter governing plant morphogenesis, flowering, and the shade-avoidance response via phytochromes.
• Spectral Growth Distribution: Detailed analysis of spectral balances (Blue/Green/Red ratio) to optimize light recipes according to the phenological stages of crops.

Mobile Ecosystem: The SpectroLight Android App

The IndiGo Light Meter eliminates the need for laptops, offering complete mobility right next to the lights or crops:

• BLE (Bluetooth Low Energy) wireless connection: Instant connection to your Android smartphone or tablet without cumbersome cables.
• Dedicated SpectroLight app: A streamlined interface designed specifically to display corrected spectra in real time, switch between LED photometry mode and horticultural PAR mode, and export your data with a single click.
• Battery Life: Up to 8 hours of continuous field measurements, with fast charging via its USB-C port.

📦 Packaging & Options: The IndiGo Light Meter ships calibrated with its built-in cosine corrector, intensity calibration preloaded in internal memory, and access to the SpectroLight Android app. The optional standard Kodak 1/4″ tripod thread is available upon request.
✉️ To request technical documentation or a quote, contact our team.

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