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Evaluate support for Bluetooth Cycling Speed and Cadence Service #1

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avanc opened this issue Aug 19, 2016 · 2 comments
Open

Evaluate support for Bluetooth Cycling Speed and Cadence Service #1

avanc opened this issue Aug 19, 2016 · 2 comments

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@avanc
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@avanc avanc commented Aug 19, 2016

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@avanc avanc commented Aug 19, 2016

The CSCS only supports raw data and does no calculations like speed or distance on the server side. Everything is calculated on the client (e.g. smartphone). However, it support a continuous counter for the wheel ticks.
Detailed explanation can be found in CSCS Overview:

The Cumulative Wheel Revolutions value, which represents the number of times a wheel rotates, is used in combination with the Last Wheel Event Time and the wheel circumference stored on the Client to determine 1) the speed of the bicycle and 2) the distance traveled. In addition, if there is link loss, the Cumulative Wheel Revolutions value can be used to calculate the average speed of the bicycle during the link loss. This value is expected to be set to 0 (or another desired value in case of e.g. a sensor upgrade) at initial installation on a bicycle as described in Section 3.4.2.1. The Cumulative Wheel Revolutions value may decrement for some implementations (e.g. If the bicycle is rolled in reverse), but shall not decrease below 0.
The ‘wheel event time’ is a free-running-count of 1/1024 second units and it represents the time when the wheel revolution was detected by the wheel rotation sensor. Since several wheel events can occur between transmissions, only the Last Wheel Event Time value is transmitted. This value is used in combination with the Cumulative Wheel Revolutions value to enable the Client to calculate speed and distance.
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The Last Wheel Event Time value rolls over every 64 seconds.

Thus, no fancy statistics are calculated on the server.

@avanc avanc changed the title Evaluate support for Bluetoth Cycling Speed and Cadence Service Evaluate support for Bluetooth Cycling Speed and Cadence Service Aug 19, 2016
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