Cover the rear camera and flash fully with a fingertip. Hold still, light but steady pressure. This reads relative light-intensity change (PPG) — not calibrated pressure or volume.
Your baseline is stored privately on this device only — never uploaded anywhere. This compares today's beat to your own past recording, not to any medical norm.
What "amplify" means here: the raw camera signal is ~98% unchanging light and ~2% heartbeat pulsing. This display subtracts the unchanging baseline and rescales just the pulsing part to fill the trace — real signal gain, not screen zoom. The gain slider adds extra rescaling on top for very faint signals.
Averaged beat, in plain terms: each individual heartbeat is noisy on its own. This panel lines up your last several beats and averages them together — random noise cancels out, and what's left is a cleaner picture of your typical beat shape. Beat shape match shows how closely your most recent beat resembles that average; a sudden drop usually means motion or contact noise, not a real change in your heart. This sensor's frame rate is too low to resolve fine sub-beat features like the dicrotic notch — treat this as a smoothed contour, not a diagnostic waveform.