No changes on reading. That's not that bad, it is showing the value I have on my watch +/- 10 but sometimes there's a little peak at 140 for example, probably due to environment magnetic noises. The bandpass I am using right now is only of first order with a high gain, so it is sensisite to the environment. The module will probably get better results.
Do you think it would be better to count the time between 3 beats for example and do the average? I would probably get a more stable output. I don't need the value that is showing to resfresh every beat.