How to build a medical and research grade ECG, PPG, EEG, etc. device for heart rate, respiration rate etc. yourself

– Take the Scott Harden Sound Card ECG: – replace the sound card by a 16 bit or higher A/D converter – connect it to an ESP 32 according to this instruction: – Scotts device is the most advanced since he is an experienced scientist writing papers: https://scholar.google.com/citations?user=egCaj-AAAAAJ&hl=en – We are experienced reviewers, and suggest …