I bought a sleep tracker from Aliexpress, which can calculate respiratory rate in real time: https://www.aliexpress.com/item/4000016737162.html?spm=a2g0s.9042311.0.0.27424c4d8PccMO Unfortunately, the Happy Sleep app said, that I was sleeping, when I was practicing breath meditation. Therefore, I was looking for a sleep tracker which is based on EEG data. I found the SpiSOP sleep lab, which is OpenBCI …