ECG detecting QRS complex in real time

Hi, I have one task, I need to detect the QRS complex in the ECG signal.

Basically, I need to detect only the R peak, however it won't hurt to detect the QRS complex.

I have a signal that is coming from a sensor device connected via the audio channel.

I need to detect the QRS complex and the R peak in real time.

There is no better place than this community was found to ask such questions.

Could you please suggest an algorithm or a sequence of algorithms to detect required part of the signal.

It would be great if you use simple functions (instead of built in) in case of any code.

Thanks