Velocity Sensor using arduino?

Projects General Guidance
1

Hi Everyone,

I would like to observe the velocity of a projectile. My plan is to build a velocity sensor with an Arduino,a bank of IR diodes and phototransistors.

My question is: How fast can the Arduino capture the information? For example, when the projectile interrupts the IR beam, does it take half a second for the Arduino to react to this event? or does this take place in half a millisecond?

Any info is appreciated! Thanks!

Matt

2

or does this take place in half a millisecond?

No, it shouldn't take that long.

3

Short answer: approximately 3 microseconds.

Long answer: Gammon Forum : Electronics : Microprocessors : Interrupts

4

Or the Input Capture Unit. It's down at the bottom of the timers page. Scroll down to the second to the bottom post about "Timing an interval using the input capture unit".

Using the input capture unit you can get sub microsecond accuracy.

5

Perfect, that is good news!

Thanks everyone for the info, much appreciated. Looks like using an Arduino for this will work out as we hoped.

Matt