how are the variable names to be?
If you are attaching a generic sensor to the pin, then sensorPin is a fine name. I don't know where to get a generic sensor, though. I know where to get LDRs. I know where to get potentiometers. I know where to get O2 sensors. NO sensors, wind speed sensors, temperature sensors, and a whole host of other sensors can be had.
You haven't said anything about this generic sensor that you have. So, it isn't clear why the sensor needs calibrating. It isn't clear why you need three of them. It isn't clear whether you need to calibrate all three of them. It isn't clear whether they can be calibrated at the same time, or whether they need to be calibrated one at a time.
Can you see, then, why it is difficult to help you?
What are these sensors? What do you want the program to do?