i would like to make a testing for a moving object.So i need to calculate the time for the object to move from point A to point B.

my idea is like this..there will be a sensor that will detect the moving object.once the object passing the sensor the time will start and another sensor at the end of the use to stop the time..

so how am i going to do this? is there any product out there similar to this? or hobby kit?

i need an idea..

light curtain sensor. Simple ones connect through serial port.
two sets, as you stated, first set to trigger the start. 2nd set to trigger the stop.
Need a controller and programming to do the calculation.
Need the input of distance as well, for it to calculate speed based on the time difference.

The more accurate and detail the distance input, the more accurate the speed.
e.g. 1.5m vs 1.498m vs 149.8cm vs 1498.3mm -> the mm will provide most accurate speed reference calculation.

im doing the same thing for my project...
can i use photoelectric sensor??

where can i get more detail about the controller and programming??
i really need a guide because im newbie in electronic world

thank you