Breatheasy

iPhone PWA that watches a baby monitor's video feed for rhythmic breathing motion.

Problem

• The real work was the measurement problem, not the plumbing.
• False positives are easy to generate — a fan, a fluttering blanket, a passing shadow all read as "motion".

Approach

• It runs in the phone's browser, points the phone's camera at the baby-monitor screen, reads a region you select, and applies a small motion-analysis pipeline to detect the rhythm of an infant's breathing.
• The pipeline is mostly signal conditioning: isolating the periodic component at breathing-plausible frequencies, gating on amplitude, and running detection through a dual-threshold hysteresis state machine.

Outcome

• Not a medical device, not aspiring to be one — an experiment in how far a camera and a signal-processing pipeline can get.
• The DSP and state machine are driven by synthetic-signal tests — sine waves in the breathing band versus pure noise.
• On-device tuning used a numbers-only telemetry loop (thresholds and confidences, never frames).