I'm currently working on a heart rate monitor. I can successfully show the heart rate (bpm) using the Heart Rate Measurement (0x2A37) characteristic of Bluetooth. But I want to show an ECG line graph so I need the raw heart data, with the voltage amounts specified. I can reach some other information such as RR-interval and sensor contact status (with this characteristic) but I don't know how to get the raw data itself. Is it possible that I'm missing a feature of this characteristic, or is there any other way I can get this data? I'm using an AD8232 heart monitor.
You should find this information in the AD8232 heart monitor device profile.
Such as examples of Arduino imlementations
Could also search here:
Gives access to all the existing characteristics
Could this tutorial help ? Probably not, it is a bit general.