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FTMS

C#

Pure managed Bluetooth Fitness Machine Service protocol library for .NET.

0.1.0-alpha.1 is published on NuGet. The interface remains an evolving prerelease.

Terminal window
dotnet add package DeanCochran.Ftms --prerelease

This explicitly includes prereleases while the package is alpha. Retain the resolved dependency in your project and use a NuGet lockfile for reproducible restores. Once stable releases are available, omit --prerelease to select those. To reproduce the recorded alpha, use dotnet add package DeanCochran.Ftms --version 0.1.0-alpha.1 instead.

Scope

Section titled “Scope”
  • Bidirectional Feature words and all five Supported Ranges.
  • Bidirectional treadmill, cross trainer, step climber, stair climber, rower and indoor bike measurements, with exact raw values and physical-unit projections.
  • All 21 Control Point requests, responses, Training Status and Machine Status.
  • Explicit range inspection and independent compatibility-format selections.
  • Static capability interpretation, including uncertain/contradictory evidence, duplicate observations, conditional Feature properties and operation reports.

Targets netstandard2.1 and net10.0, with no runtime package dependencies. Inputs use ReadOnlySpan<byte>; encoders return fresh arrays or write to caller spans after validation. Retained bytes and collections are defensively copied.

Integrate through the consumer adapter seam: transport conversion, BLE/session lifecycle, retries, subscriptions, UI/application policy and control safety remain outside this protocol package.

Decode a measurement

Section titled “Decode a measurement”
using DeanCochran.Ftms;


var result = MeasurementCodec.TryDecode(MeasurementKind.IndoorBike,
    new byte[] { 0x44, 0x00, 0x10, 0x0e, 0xb4, 0x00, 0xfa, 0x00 });
if (result.Success)
{
    var measurement = result.Value!;
    System.Console.WriteLine(measurement.Normalized.SpeedMetresPerSecond); // 10
    System.Console.WriteLine(measurement.Normalized.CadenceRpm);           // 90
    System.Console.WriteLine(measurement.Normalized.PowerWatts);          // 250
}

These are synthetic bytes, not a device capture. A successful raw decode can still contain truncation or other diagnostics: inspect measurement.Diagnostics. An absent raw field was not read; a present field with a null value is an explicit unavailable sentinel, not zero.

Build and verify from source

Section titled “Build and verify from source”

Run from packages/csharp/ with the SDK pinned in global.json, Python 3.10+, Git, and Bash (Git Bash on Windows). A virtual environment is recommended for the test-only schema validator:

Terminal window
python3 -m pip install -r verification/requirements.txt
bash verification/verify.sh

This runs native unit tests, canonical conformance, the independent structural matrix, local packing, portable-symbol/Source Link metadata checks and isolated installed consumers of both target assemblies. Artifacts and evidence are written under ignored artifacts/. No command publishes or operates equipment.

On a Linux x64 host with the .NET NativeAOT compiler prerequisites installed:

Terminal window
FTMS_VERIFY_AOT=1 bash verification/verify.sh

VERSION is the sole package-version authority. After verification, a local consumer can restore from the absolute artifacts/packages directory:

Terminal window
dotnet add package DeanCochran.Ftms --version 0.1.0-alpha.1 --source /absolute/path/to/artifacts/packages

Boundaries and evidence

Section titled “Boundaries and evidence”

There is no BLE stack, connection lifecycle, timer, logging, UI framework, control ownership or execution authorization in this library. Capability prerequisites being satisfied does not authorize transmitting a command or moving equipment. Fragment planning/assembly is outside this initial package.

Linux host verification does not prove Windows/macOS CI execution, Unity/IL2CPP, MAUI mobile runtime compatibility, real-device interoperability or Bluetooth qualification. A .NET Standard target is an integration opportunity, not a tested Unity claim. Classic .NET Framework is not supported by these targets.

Source-checkout documentation:

Those repository links identify intended main-branch locations.