How do you make working model of sphygmomanometer?

A working model would serve the same function as the real thing and would have to be large enough to be used to be a working model. Therefore, if you want to make a blood pressure meter that is simply not as accurate as a real sphygmomanometer (such as for a school science project), you can use parts found at an auto parts store - such as a bicycle tire tube, a small pump, an air pressure gauge, small tubing, and the tire glue that can hold the parts together. The only thing missing is Velcro for a fastener (even supermarkets sell that today).