Blood pressure meter teardown / Vacuum cleaner motor regulator reverse engineering

First time opening the blood pressure meter. What would I find there? No pressure, just pleasure. Or maybe the other way? Reverse engineering a power adjustment circuit from a vacuum cleaner. 0:00 Intro 0:28 Blood pressure meter teardown 3:10 Going over the electronic part 5:50 How the thing works 7:20 Why does it talk? Overengineering? 7:50 Possible explanation 10:00 Vacuum cleaner regulator reverse engineering 11:47 SMD resistor marking shenanigans 15:25 Initial schematic 23:15 Redrawing the schematic 31:00 Outro Support me on my Patreon page at https://www.patreon.com/KeritechElectronics Instagram - https://www.instagram.com/KeriSzafir Telegram - https://t.me/KeritechElectronics