BLE CSCS cadence value problem

RE: BLE CSCS cadence value problem

Hakon — Thu, 16 Aug 2018 08:21:33 GMT

https://www.bluetooth.com/specifications/gatt/viewer?attributeXmlFile=org.bluetooth.service.cycling_speed_and_cadence.xml

It looks to me like it's fine.

RE: BLE CSCS cadence value problem

cavalihno — Wed, 15 Aug 2018 14:37:19 GMT

What do You think about this solution (which works correctly for everyone third party app's):

    // Calculate simulated cadence values.
    p_measurement->is_crank_rev_data_present = true;
    degrees_per_sec = RPM_TO_DEGREES_PER_SEC * RPM;

    crank_rev_degrees     += degrees_per_sec;
    cumulative_crank_revs += crank_rev_degrees / DEGREES_PER_REVOLUTION;
    crank_rev_degrees     %= DEGREES_PER_REVOLUTION;

    if(cumulative_crank_revs > last_cumulative_crank_revs){
      p_measurement->cumulative_crank_revs = cumulative_crank_revs;
      p_measurement->last_crank_event_time = event_time + (1024 * (degrees_per_sec - crank_rev_degrees) / degrees_per_sec);
      last_cumulative_crank_revs = p_measurement->cumulative_crank_revs;
      last_last_crank_event_time = p_measurement->last_crank_event_time;
    }else{
      p_measurement->cumulative_crank_revs = last_cumulative_crank_revs;
      p_measurement->last_crank_event_time = last_last_crank_event_time;
    }

    event_time += event_time_inc;

Is it correct in terms of Gatt specifications ?

RE: BLE CSCS cadence value problem

Hakon — Wed, 15 Aug 2018 12:14:06 GMT

I tried it, and I got the same result as you. It happens because last_crank_event_time isn't updated every time the measurement is sent to the phone application. This happens if the RPM is below 60.

If you want to know why, read this file

https://github.com/NordicSemiconductor/Android-nRF-Toolbox/blob/master/app/src/main/java/no/nordicsemi/android/nrftoolbox/csc/CSCService.java

The crank measurement is handled in onCrankMeasurementReceived(). As for the Wahoo application, I assume the behavior is similar to nRF toolbox and that's the reason it reads 0 most of the time.

RE: BLE CSCS cadence value problem

cavalihno — Mon, 13 Aug 2018 14:39:13 GMT

Still the same effect.stock example from SDK15, s132_nrf52_6.0.0_softdevice

Please try wit Wahoo ultility

RE: BLE CSCS cadence value problem

cavalihno — Mon, 13 Aug 2018 14:23:42 GMT

Try to set other values from range 0 - 50rpm;

RE: BLE CSCS cadence value problem

Hakon — Mon, 13 Aug 2018 14:00:04 GMT

Hmm, that's strange. I installed the wahoo fitness app and tried the example and it worked for me. It reads 40 rpm all the time. Perhaps you can try reinstalling the SDK, and make sure you download it from this location http://developer.nordicsemi.com/nRF51_SDK/nRF5_SDK_v12.x.x/. Then you can compile the example unmodified and see if it works, and if it does you can then try to modify it and see if it still works.

RE: BLE CSCS cadence value problem

cavalihno — Mon, 13 Aug 2018 13:28:13 GMT

I know, but what with compatibily with third-party apps and BLE GATT specification ? Please look for thisscreen recorder from third-party apps

https://youtu.be/rlbx2Nth0RU

https://youtu.be/ml3K6rgFIgA

RE: BLE CSCS cadence value problem

Hakon — Mon, 13 Aug 2018 12:54:00 GMT

I suggest you use the nRF toolbox application with the cscs example. If you need your own functionality, you can implement it yourself by using the source code for the nRF toolbox found here,

github.com/.../Android-nRF-Toolbox
github.com/.../IOS-nRF-Toolbox

RE: BLE CSCS cadence value problem

cavalihno — Mon, 13 Aug 2018 12:43:32 GMT

I look like everything is fine with nRf Toolbox. But when I am using third-party app like "Strava", "Wahoo fitness" "Motosumo" this bug occured.

RE: BLE CSCS cadence value problem

Hakon — Mon, 13 Aug 2018 12:12:37 GMT

It looks like you have a different application than the one I'm using. Try downloading the "nRF Toolbox for BLE" application on your phone, and see if the problem persists.

RE: BLE CSCS cadence value problem

cavalihno — Mon, 13 Aug 2018 12:00:50 GMT

Now I am using stock examle from SDK15. Just hardoce crank revolution = 40;

// Calculate simulated cadence values.
    p_measurement->is_crank_rev_data_present = true;

    degrees_per_sec = RPM_TO_DEGREES_PER_SEC * 23; //sensorsim_measure(&m_crank_rpm_sim_state, &m_crank_rpm_sim_cfg);

    crank_rev_degrees     += degrees_per_sec * SPEED_AND_CADENCE_MEAS_INTERVAL / 1000;
    cumulative_crank_revs += crank_rev_degrees / DEGREES_PER_REVOLUTION;
    crank_rev_degrees     %= DEGREES_PER_REVOLUTION;

    p_measurement->cumulative_crank_revs = cumulative_crank_revs;
    p_measurement->last_crank_event_time =
        event_time + (event_time_inc * (degrees_per_sec - crank_rev_degrees) / degrees_per_sec);

    event_time += event_time_inc;

Plese look for screen recorder from Android app:

https://youtu.be/YAJQy5uj--E

RE: BLE CSCS cadence value problem

Hakon — Fri, 10 Aug 2018 14:34:13 GMT

My code (using SDK version 12.1.0) looks like this;

static void csc_sim_measurement(ble_cscs_meas_t * p_measurement)
{
    static uint16_t cumulative_crank_revs = 0;
    static uint16_t event_time            = 0;
    static uint16_t wheel_revolution_mm   = 0;
    static uint16_t crank_rev_degrees     = 0;

    uint16_t mm_per_sec;
    uint16_t degrees_per_sec;
    uint16_t event_time_inc;

    // Per specification event time is in 1/1024th's of a second.
    event_time_inc = (1024 * SPEED_AND_CADENCE_MEAS_INTERVAL) / 1000;

    // Calculate simulated wheel revolution values.
    p_measurement->is_wheel_rev_data_present = true;

    mm_per_sec = KPH_TO_MM_PER_SEC * sensorsim_measure(&m_speed_kph_sim_state,
                                                       &m_speed_kph_sim_cfg);

    wheel_revolution_mm     += mm_per_sec * SPEED_AND_CADENCE_MEAS_INTERVAL / 1000;
    m_cumulative_wheel_revs += wheel_revolution_mm / WHEEL_CIRCUMFERENCE_MM;
    wheel_revolution_mm     %= WHEEL_CIRCUMFERENCE_MM;

    p_measurement->cumulative_wheel_revs = m_cumulative_wheel_revs;
    p_measurement->last_wheel_event_time =
        event_time + (event_time_inc * (mm_per_sec - wheel_revolution_mm) / mm_per_sec);

    // Calculate simulated cadence values.
    p_measurement->is_crank_rev_data_present = true;

    degrees_per_sec = RPM_TO_DEGREES_PER_SEC * 40;

    crank_rev_degrees     += degrees_per_sec * SPEED_AND_CADENCE_MEAS_INTERVAL / 1000;
    cumulative_crank_revs += crank_rev_degrees / DEGREES_PER_REVOLUTION;
    crank_rev_degrees     %= DEGREES_PER_REVOLUTION;

    p_measurement->cumulative_crank_revs = cumulative_crank_revs;
    p_measurement->last_crank_event_time =
        event_time + (event_time_inc * (degrees_per_sec - crank_rev_degrees) / degrees_per_sec);

    event_time += event_time_inc;
}

Perhaps you could try replace your code with the code above.

RE: BLE CSCS cadence value problem

cavalihno — Fri, 10 Aug 2018 13:59:30 GMT

#define RPM_TO_DEGREES_PER_SEC 6

#define BICYCLE_POWER_MEAS_INTERVAL 1000

static void cp_sim_measurement(ble_cp_meas_t * p_measurement)
{
    static uint16_t cumulative_crank_revs = 0;
    static uint16_t event_time            = 0;
    static uint16_t crank_rev_degrees     = 0;

    uint16_t degrees_per_sec;
    uint16_t event_time_inc;

    // Per specification event time is in 1/1024th's of a second.
    event_time_inc = (1024 * BICYCLE_POWER_MEAS_INTERVAL) / 1000;

    // Calculate simulated cadence values.
    p_measurement->is_crank_rev_data_present = true;

    degrees_per_sec = RPM_TO_DEGREES_PER_SEC * 40;

    crank_rev_degrees     += degrees_per_sec * BICYCLE_POWER_MEAS_INTERVAL / 1000;
    cumulative_crank_revs += crank_rev_degrees / DEGREES_PER_REVOLUTION ;
    crank_rev_degrees     %= DEGREES_PER_REVOLUTION;

    p_measurement->cumulative_crank_revs = cumulative_crank_revs;
    p_measurement->last_crank_event_time =
           event_time + (event_time_inc * (degrees_per_sec - crank_rev_degrees) / degrees_per_sec);

    event_time += event_time_inc;
}

RE: BLE CSCS cadence value problem

Hakon — Fri, 10 Aug 2018 13:52:25 GMT

Can you provide the code so I can see what you have done?

RE: BLE CSCS cadence value problem

cavalihno — Fri, 10 Aug 2018 13:47:14 GMT

No, I only hardcode Crank Revolution value ex. 40rpm.

RE: BLE CSCS cadence value problem

Hakon — Fri, 10 Aug 2018 13:43:18 GMT

Have you done any modifications to the original example code?

RE: BLE CSCS cadence value problem

cavalihno — Fri, 10 Aug 2018 09:59:11 GMT

Yes, i am using ble_app_cscs. Also cadence value i mean "Crank Revolution".

May i try explain it:

If measured Crank Revolution is less than 50rpm my monitor occasionaly shows 0rpm despite the sended value is still the same. I think that it is related with cumulative_crank_revs and last_crank_event_time.

RE: BLE CSCS cadence value problem

Hakon — Fri, 10 Aug 2018 09:03:24 GMT

Ok, can you please specify the following?

Is it the "ble_app_cscs" example you are referring to?

By "cadence value", do you mean crank rev?

What is "BICYCLE_POWER_MEAS_INTERVAL"?

RE: BLE CSCS cadence value problem

cavalihno — Thu, 09 Aug 2018 15:35:21 GMT

Hi, I am using SDK12.1.0.

RE: BLE CSCS cadence value problem

Hakon — Thu, 09 Aug 2018 11:06:57 GMT

Hey, which SDK version are you using?