increase sampling rate for CC2650STK sensortag

Zainab Mones

Prodigy 45 points

is it possible to increase sampling rate of sensors on CC2650STK to be more than 10 Hz?

Thanks

over 10 years ago

0 YiKai Chen over 10 years ago

Guru 735685 points

You can change the following define.
// How often to perform sensor reads (milliseconds)
#define SENSOR_DEFAULT_PERIOD 1000

0 Arthur Pitman over 10 years ago

Intellectual 305 points

I'm also exploring this. So far, I've found and intend to change SENSOR_MIN_UPDATE_PERIOD in SensorTagApp/PROFILES/st_util.h.

The following lines are of interest:

// Data readout periods (range 100 - 2550 ms)
#define SENSOR_MIN_UPDATE_PERIOD        100     // Minimum 100 milliseconds
#define SENSOR_PERIOD_RESOLUTION        10      // Resolution 10 millisecond

Changing SENSOR_MIN_UPDATE_PERIOD to 10 should increase the maximum to 100Hz, I don't think much faster would work as the BLE minimum connection period is about 8 milliseconds. I've also heard the current maximum rate is due to the coin cell constraint,

0 YiKai Chen over 10 years ago in reply to Arthur Pitman

Guru 735685 points

The connection period in BLE stack is 7.5 milliseconds so it is meaningless to decrease sample period shorter than it.

0 Zainab Mones over 10 years ago in reply to Arthur Pitman

Prodigy 45 points

Thank you for replying me. I will try that.

0 YiKai Chen over 10 years ago in reply to Zainab Mones

Guru 735685 points

You are welcome.

0 user4687891 over 9 years ago in reply to YiKai Chen

Prodigy 120 points

Hi Yikai

Actually I did the same thing, I mean that I increase the sampling rate by changing those constants and It was around 100Hz
but you comment pose a challenge to me, which maybe I am not quite accurate in tracking sampling rate.
would you mind please give me further information about sampling rate limitation over BLE

Best Regards
Reza

0 YiKai Chen over 9 years ago in reply to user4687891

Guru 735685 points

Can you elaborate your question?

0 user4687891 over 9 years ago in reply to YiKai Chen

Prodigy 120 points

Do you know, how high we can increase sample rate to have valid data?

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increase sampling rate for CC2650STK sensortag