How to build a low-cost high-quality 3 channel ECG gold standard device & spirometer

We choose an Orange Pi 5 as a platform for a 3 channel gold standard ECG device & spirometer for the reasons we indicated on www.petergamma.org. The Orange Pi 5 is bulky, but still better than the iWorx TA 220: We are physiologist and not soft- and hardware developers. We have already listed all components …