Your watch won't let you nap.
Daytime dozing steals your night. NapBuster reads your heart rate, spots a nap forming in minutes, and buzzes it away — entirely on your Pebble.
A background worker guards your configured no-nap hours with two-tier detection. Heart rate is the primary signal — as you drift off, your HR sinks below your awake baseline. Motion — movement intensity and step counts alike — is the gate that rules out false alarms while you are up and about.
Every real heart-rate reading is judged the moment it arrives. When the median-filtered value sits 8–16% (your choice) below your calibrated awake baseline and motion agrees you are genuinely still, a candidate episode opens and the clock starts.
After ~4 minutes of sustained evidence: a quiet double pulse. If you were just relaxing, you'll barely notice. If you were drifting off, it's enough to break the slide.
Still sinking at ~10 minutes? The full repeating alarm fires and keeps buzzing until you dismiss it — or snooze for 10/30 min if you've earned it.
Your reference HR calibrates only from clustered readings taken while you are genuinely still — and a falling heart rate never forms a stable cluster, so it cannot quietly calibrate itself to a doze. It then holds frozen for the whole of an episode.
On every Pebble — including watches without a heart-rate sensor — the OS's own sleep classification is a fallback trigger. Slower (45–90 min), but it catches what Tier 1 can't.
Sensors idle outside your no-nap window. Inside it NapBuster rides the readings the watch already takes, and only probes faster once a candidate episode opens — to confirm or clear it — then backs off again. Nothing ever leaves the watch.
The detection core is plain C with no watch dependencies, so it runs on a laptop against 13 scenario tests — exact alert boundaries, clock jumps, missing data, calibration. CI runs them on every change, and a release cannot be built unless they pass.
Every genuine heart-rate reading is judged on arrival — no stale value is ever replayed as fresh evidence.
Gentle nudge first; the full alarm only if you keep sinking. Both time-based, not sample-count roulette.
10 or 30 minutes via the Wakeup API — works even if the app closes.
Guard weekdays, weekends, or any custom set of days and hours.
Gentle, Medium, Strong — pulse-density patterns, test-buzzed as you pick.
Sensitive / Balanced / Conservative HR-drop thresholds to match your physiology.
HR, baseline, motion, phase and evidence timing right on the watch face — see it working.
OS sleep classification backs up the HR engine on all supported watches.
| Platform | Watch | Detection |
|---|---|---|
| emery | Pebble Time 2 (primary target) | Tier 1 (HR + motion) + Tier 2 |
| diorite | Pebble 2 HR | Tier 1 (HR + motion) + Tier 2 |
| basalt | Pebble Time / Time Steel | Tier 2 only (no HR sensor) |
| chalk | Pebble Time Round | Tier 2 only (no HR sensor) |
Requires Pebble Health enabled in the rePebble mobile app (Devices → Health).
# one-time: pebble-tool needs Python 3.11 uv venv ~/.pebble-venv --python 3.11 ~/.pebble-venv/bin/pip install pebble-tool ~/.pebble-venv/bin/pebble sdk install latest # build git clone https://github.com/JoLeungGitHub/nap-buster.git cd nap-buster ~/.pebble-venv/bin/pebble build # → build/napbuster.pbw # install to your watch (enable Dev Connect in the rePebble app first) ~/.pebble-venv/bin/pebble login ~/.pebble-venv/bin/pebble install --cloudpebble
Full SDK setup instructions at developer.repebble.com/sdk.