C/C++ :: Comparing Time-based-responses From Two IR Sensors (Arduino)

I am building a project with an Arduino Uno that involves using analogue IR sensors to detect fast motion. By placing one sensor on top of the other, I want to be able to attain a variable integer from the difference in time between the responses of the sensors.

Here is my code I have so far, it is essentially for detecting motion for 1 sensor and then converting it into a MIDI note depending on how far away the motion is detected. There is also a part which compares the value from the previous time so that only above a certain amount of movement will trigger the note. I also have a variable delay to be controlled by a potentiometer.

Here is the datasheet for the sensors I'm using.

#include <MIDI.h>
MIDI_CREATE_DEFAULT_INSTANCE();

int currentvalA = 0; //current sensor A value
int previousvalA = 0; //previous sensor A value
int valA = 0; // value to store sensor
const int valchangeA = 40; //motion change value
int del = 0; //variable delay value

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