Read input to change an output

This is a high level yes or no question. I am just getting started being interested in the Arduino. I have programmed in Visual Basic and I have used the eagle schematic program to design,etch, and solder components on a board so while I’m not totally profecient with Arduino, I think I can still stumble around in it. My question is, can I create an Arduino tachometer , run a timer for a minute or so, then reading the rpm , slo down down a motor to a different rpm. I guess what I am asking is can I do an input and output at the sam time? T(ants

As a high level Yes or No question, can you output and input on a arduino at the EXACT same time the answer is no.

Can you do it within a millionth of a second of each other, almost.

How fast is that motor going to be spinning?

My question is, can I create an Arduino tachometer , run a timer for a minute or so, then reading the rpm , slo down down a motor to a different rpm

Yes.

I guess what I am asking is can I do an input and output at the sam time?

You guess wrong. No you can’t do it at the same time, but then you don’t need to.

RPM is between 2,300 to 18,000.

Would an example be:

read rpm
if rpm between ### and ### then change
loop

Yes that sort of thing is what you need to do.