Need help integrating pulsesensor heart beat sensor.

[sid]

Hello developers, I am trying to use ble_hrm service example with actual heart rate from the module pulsesensor.com (http://pulsesensor.com/) I am able to read raw data using ADC but I am not able to figure out how to get beats per minute data from this. The module has arduino library, if some one has already made a library for this module or a similar module kindly help me with this.

Thank you and my best regards, Sid

[Stefan Birnir Sverrisson]

Hi Sid

Thanks for the additional information.

There are some nRF51 ADC examples on Nordic Github for SDK 11 if you didn't notice already. I suspect that you need to sample the pulse sensor voltage with certain constant frequency, using TIMER/RTC+PPI.

As an idea on how to calculate heart rate from the ADC signal, you could detect when there is a pulse with monitoring when there is a sudden increase in the ADC value. When there is a pulse, you can create a time-stamp for that pulse. Every time there is a pulse you also calculate the pulse frequency from e.g. the last 5 time-stamps.

You can create the time stamp by checking the counter value of TIMER/RTC.

[sid]

Thank you Stefan, I will make a library and upload it here so that others can benefit as well.