need help making midi sensor

repeat of last post with sensible title sorry
I',m quite new to musical keyboards. I have a high school science
project I'm working on where I want to use a midi to measure reaction
times, pressure (volume) and time duration for people pressing a key in
response to a stimulus (flashing light). I want to do this for 2 keys;
one for the left hand and one for the right, i want to separate the 2
keys far enough that it is not practical to use one hand to press both
keys. When I googled all the devises werevery fancy and accurate, and
expensive. This can be accurate to 1 100th of a second, and whatever
the same pressure measurement accuracy would be.

All MIDI keyboards use time alone to evaluate key pressure for note velocity, and are not really pressure sensors. It seems that the time it takes a key to move from start to end position is directly proportional to the actual pressure used by the musician. Maybe you can use this concept yourself and it may make it more cost effective for you to only have to set up time based triggers.