Chrono question

[dsiegel]

I have been tasked with redesigning a chronometer that is in a ballistic tester at my work, my issue is that i have a nice off the shelf front end that I think may be usable with the UV sensors that are in place, the issue is that the front end requires a spacing of 24in between the sensors for accurate reading. I believe that I can accomplish with a clock multiplier that will multiply the 3in that is currently between the sensors by 8 and that will give me the numbers I am looking for, thinking behind the clock multiplier is that the sensors pulse when something obstructs them, sending out a square wave. Am I correct in my assumption that this will work, or what? Any help is appreciated.

 

[crutschow]

What is the chronometer measuring? How does the distance between sensors affect the measurement?

 

[dsiegel]

it is measuring the time between the pulses and giving a number in fps

first sensor would be kind of an ON and second would be OFF I believe

 

[crutschow]

It may just be determining the time between the two signals going off and on, not the frequency of the signal. If so, changing the frequency won't help. Do you know the frequency of the signal?

You could, of course, just multiply the reading you get by 8, but that may not give you a very accurate reading.

 

[dsiegel]

yeah, math would be okay for here, but if it was ever going to be manufactured, which is another of my tasks, to simplify the design and make it a bit more user friendly and cheaper it wont work, which is why i was thinking of something along these lines. But no, i don't know the frequency, yet, ill hook a scope up to it and see, never paid attention to it before, but that is the calibration method currently. What I am really trying to do would be to increase the time between the pulses x8 so that the numbers would out correct.

 

[smanches]

You could multiply the time between pulses by 8, but you're also going to modify the error by 8 as well.

Is this for paintball/airsoft or real firearms?

 

[dsiegel]

ballistics testing, so it has to be pretty spot on

 

[smanches]

I would not even attempt it at 3in then if it's meant for 24in. There would be too much error otherwise.