BLE Cycling Power meter support #50

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opened 2026-08-31 17:25:16 +02:00 by robert · 0 comments

robert commented

2026-08-31 17:25:16 +02:00

(Migrated from git.butzei.de)

Goal

Support a power meter over the standard BLE Cycling Power profile. Unlike cadence this is a genuine addition: a separate profile, its own client and its own derived metrics.

Acceptance criteria

Cycling Power service 0x1818 discovered and connected
Cycling Power Measurement 0x2A63 parsed, including the variable-length flags field
Instantaneous power in watts sent to the watch and shown as a ride data field
3-second rolling average power computed, since raw power is far too jittery to read while riding
Normalised power and average power for the ride computed and shown in the summary
Crank-based cadence taken from the power meter when it supplies it, in preference to a separate CSC sensor
Power written into the recorded GPX
Pairing and calibration flow in the companion, including zero-offset where the meter supports it
Sits behind the same sensor interface as speed and cadence, so dropout handling is shared

Files

companion/.../sensors/CyclingPowerClient.kt
watchapp/src/c/view_ride.c

Notes

The flags field makes this parser materially more involved than CSC - fields are optional and their offsets shift. See docs/DECISIONS.md D16.

## Goal Support a power meter over the standard BLE Cycling Power profile. Unlike cadence this is a genuine addition: a separate profile, its own client and its own derived metrics. ## Acceptance criteria - [ ] Cycling Power service `0x1818` discovered and connected - [ ] `Cycling Power Measurement` `0x2A63` parsed, including the variable-length flags field - [ ] Instantaneous power in watts sent to the watch and shown as a ride data field - [ ] 3-second rolling average power computed, since raw power is far too jittery to read while riding - [ ] Normalised power and average power for the ride computed and shown in the summary - [ ] Crank-based cadence taken from the power meter when it supplies it, in preference to a separate CSC sensor - [ ] Power written into the recorded GPX - [ ] Pairing and calibration flow in the companion, including zero-offset where the meter supports it - [ ] Sits behind the same sensor interface as speed and cadence, so dropout handling is shared ## Files - `companion/.../sensors/CyclingPowerClient.kt` - `watchapp/src/c/view_ride.c` ## Notes The flags field makes this parser materially more involved than CSC - fields are optional and their offsets shift. See docs/DECISIONS.md D16.