FlickerSpec

Download FlickerSpec from the App Store, point your iPhone camera at any LED light source, and tap Measure. The app uses your camera sensor and FFT spectral analysis to calculate percent flicker, flicker index, and dominant frequency in seconds — no external hardware needed.

FlickerSpec uses the same FFT-based analysis methodology as professional hardware meters. Each measurement includes a confidence rating (High/Medium/Low) and measurement uncertainty percentage. For most lighting inspection scenarios, phone-based measurement is sufficient for IEEE 1789 compliance screening. Dedicated hardware meters like the UPRtek MF250N ($1,200+) offer higher sampling rates for research-grade applications.

Percent flicker measures the relative variation in light output as a percentage (0% = no flicker, 100% = full on/off cycling). Flicker index (0 to 1.0) accounts for the waveform shape and is a more complete metric. Both are defined by IEEE 1789-2015 and IES standards for evaluating temporal light artifacts in LED lighting.

Yes. FlickerSpec evaluates measurements against IEEE 1789-2015 recommended practices and provides a Pass/Fail verdict based on the standard's risk thresholds for flicker frequency and modulation depth. Pro users get this compliance status included in generated PDF reports.

PstLM (short-term flicker severity, light-side variant) is the standardized single-scalar metric for how perceptually annoying a time-varying light source is to a human observer. PstLM = 1.0 corresponds to the visibility threshold (50% probability of detection by an average observer). EU Ecodesign uses PstLM ≤ 1.0 as the threshold for SLR (Single Lighting Regulation) compliance. FlickerSpec computes PstLM per IEC TR 61547-1:2015 Annex A — the same perceptual metric a $1,200+ hardware flicker meter produces.

Quick Measurement is the original FlickerSpec flow — live IEEE 1789-2015 capture at 240 fps, real-time waveform, takes seconds. IEC Certified Measurement (Pro, iOS) is a 180-second tripod-based capture that runs the full IEC TR 61547-1 light-flickermeter pipeline (8× polyphase upsample to 1920 Hz, perceptual weighting, statistical evaluation) to produce a PstLM number valid for EU Ecodesign reporting. Use Quick for screening; use Certified when you need defensible PstLM evidence.

Not yet — SVM (Stroboscopic Visibility Measure, 80 Hz – 2 kHz) and PAVM (Phantom Array Visibility Measure) cover frequencies above the 240 fps camera's 120 Hz Nyquist limit. We're designing a purpose-built photodiode attachment to extend FlickerSpec into that band. Sign up via the contact form to be notified when it ships.

FlickerSpec is free to download and perform Quick (IEEE 1789) measurements. The Pro upgrade ($149.99, one-time purchase) unlocks: IEC Certified Measurement (180-s PstLM per IEC TR 61547-1:2015), saving measurements to a local database, professional PDF report generation (single measurement and session summary, with PstLM + EU Ecodesign threshold sections when applicable), CSV data export, and calibration certificate generation. Free users can take Quick measurements and see all data but cannot save or export.

FlickerSpec is used by lighting designers, electrical engineers, building inspectors, energy auditors, LED manufacturers, and facility managers who need to measure and document light flicker for compliance, quality assurance, or health and safety purposes.