Recently I bought a sphygmomanometer to track my parents' blood pressure. Thanks to Vinnie, I can now proudly claim that I can measure blood pressure using the manual instrument!! A couple of doctors advised me against going for the digital apparatus, saying that with time, the readings become unreliable. Moreover, its fun learning something new ;) Turns out, there is more physics involved in this than the knowledge of bio!
Heres a nice online guide that I just found.