Im using an arduino and two sets of beam breaks IR to measure the velocity of an object that is passing through the two points where the beam breaks are placed. The distance of the first beam break is $9$in and the other one is $11$in$.$ I need help writing the code for it becasue the current one I wrote is only taking the time that the object is passing through the two beam breaks. Can the code be in C$++$ please and an explanation too.