Latest note
【TECH】Local-first health data design in MonoPump
How MonoPump keeps heart-rate history useful without turning private measurements into cloud data or medical claims.
privacylocal-firsthealth dataiOS
MonoPump
Development journal
MonoPump notes
Notes from building MonoPump: product updates, small decisions, and technical details from the workbench.
MonoPump
MonoPump posts
【TECH】The state machine behind a calm heart-rate measurement
Why MonoPump treats measurement as a staged state machine instead of a single start-and-stop camera action.
【TECH】Counting beats: peak detection and BPM estimation
How MonoPump turns a cleaned PPG waveform into BPM using peak spacing, timestamp intervals, outlier filtering, and EMA smoothing.
【TECH】From camera frames to a heartbeat signal
How a stream of red-channel measurements becomes a usable PPG waveform through timing, detrending, smoothing, and buffering.
【TECH】Detecting whether a finger really covers the camera
How MonoPump uses color ratios, brightness bounds, red dominance, and frame smoothing to decide when measurement can begin.
【TECH】Camera PPG: why a phone camera can see a pulse
A practical explanation of how MonoPump turns camera frames, flash light, and blood-volume changes into a pulse signal.