I have relatively little experience with electronics, but do have a basic understanding. I am attempting to build a measuring device, which will measure 100 points in 0.1 seconds. These will all produce a digital number which will need to be stored on a micro controller.
If I were to use the raspberry pi model b, it only has 17 input GPIO pins. My question is that is there a relatively simple way of taking more inputs than the micro controller has pins?
Currently the way I am looking at doing it is having an output which sends a number to choose which input to read, that sensor would then send its current value back to the micro controller. The disadvantage of this method is obviously that it takes up time. I want 100 inputs in the order of 10^-3 seconds and I assume that this has to be a fairly common feature of circuit design given most systems have a large numbers of sensors.
So, is there an easy way of doing it? Is the way I have detailed above at all sensible? Is this a common problem, if so how is it normally overcome?