Enhance Sleep Tracking logic to make use of heart rate and spO2 data

[SULLYvin]

Is there an existing issue for this?

• I have searched the existing issues

Proposed feature request

Describe the problem

Sleep detection currently appears to rely primarily on accelerometer (motion) data. This leads to:

• False positives when the user is inactive but awake (e.g., reading, watching TV)
• Missed sleep onset when there is little movement
• No ability to assess sleep quality or fragmentation

Newer Pebble-compatible hardware includes heart rate (HR) and SpO₂ sensors, but these are not used in sleep detection.

Describe the solution you'd like

Enhance sleep detection by incorporating additional sensor data:

• Heart rate trends (e.g., sustained decrease from baseline)
• SpO₂ stability
• Combined with existing accelerometer data

Example heuristic:

Low movement + decreasing HR + stable SpO₂ → likely asleep

This could start as a simple rule-based model and evolve over time.

Additional context

• Should gracefully fall back to accelerometer-only on devices without HR/SpO₂
• Should be optional or configurable to avoid battery impact
• Could serve as a foundation for future features (sleep quality scoring, sleep stages)

Why this would be useful

Using available biometric sensors would significantly improve sleep detection accuracy and bring PebbleOS closer to modern wearable capabilities, while maintaining its lightweight design philosophy.

Alternatives

No response

Anything else?

No response

[kescherCode]

Which Pebble has an SpO₂ sensor? There is none.

[ericmigi]

PT2 has one! But this is definitely not on our roadmap...if someone else wants to add it we'd be happy to review a PR.

[kescherCode]

Huh, really? I was completely unaware!