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Connect Fenix 7 to Keiser M3I with M Series Converter

RunningFree2010
9 months ago

I own the Keiser M3I indoor bike.  Great ride btw.  I upgraded my Garmin watch from the Fenix 5 to 7X Pro.  My previous watch Fenix 5 connects to the bike speed sensor.  Also known as the M Series Converter.  I could see on my watch speed and cadence and I clearly know how to connect.  But my new watch does not connect.  What gives?  How can I connect the newer Fenix 7?

  • 0 6 months ago

    I am currently facing the same issue with my Fenix8. I have researched the issue and hope to publish an open source workaround using Raspberry Pi.

    Technical: The M3i bike itself is a bluetooth low energy beacon using a proprietary format. Custom software necessary to read it. It is not connectable as a bluetooth server.

    The Keiser bluetooth adapter accessory reads the beacon data and converts to connectable bluetooth services using standard protocols; Heart Rate Service, Cycling Power Service; and Cycling Speed and Cadence Service.

    Unfortunately, Garmin decided in newer watch software to only recognize one service per device—in this case the Heart Rate. Which is useless and the M3i’s heart rate data is actually only a rebroadcast of a heart strap like Polar H10.

    I am told other “clients” like Peloton and Zwift properly read all services associated with a BLE device—and they get power, speed, and cadence.