Speed Trap Trigger Help

[Gerthex]

Hello all,

I am newer to labview. I am creating a speed trap. We have 3 laser eyes Start, Stop (calculate), and Reset. The speed trap is a 22' in length and we are recording how long it takes to travel that 22' distance to calculate speed. 

I am struggling to figure out how to trigger a timer to gather time (obviously) via the first laser eye. I would then need another trigger for hitting the stop eye.

Can anyone assist? Thanks!

[GerdW]

Hi Gerthex,

---

@Gerthex wrote:

I am creating a speed trap. We have 3 laser eyes Start, Stop (calculate), and Reset.

---

1. How do you measure those 3 "eyes"? Are these 3 digital inputs?
2. What happens when the object does not hit the "Reset" trigger?
3. Which object do you want to track? How fast will it move?
4. Which hardware do you want to use? Does it allow to measure DI signals hardware-timed?
5. In case your DI inputs only allow software-timed readings: Does the answer to question 2 allow to read those DIs at ~100 Hz?
6. In case you need more (timing) accuracy: could you use hardware-timed AI channels instead of software-timed DI channels?
7. Why do you stick with feets and miles when there is SI?
8. …

So many questions, so little information from your side… 😄

[Gerthex]

1. How do you measure those 3 "eyes"? Are these 3 digital inputs?
   1. Digital Input. 24V source.
2. What happens when the object does not hit the "Reset" trigger?
   1. I was going to do a timeout option so if reset was not triggered after X time it would auto reset.
3. Which object do you want to track? How fast will it move?
   1. The object I want to measure tops out at 10mph.
4. Which hardware do you want to use? Does it allow to measure DI signals hardware-timed?
   1. I have not picked out hardware yet. I am unfamiliar with what a DI signal is. Assuming Digital Input? If so, our hardware we have available probably only measures the signal.
5. In case your DI inputs only allow software-timed readings: Does the answer to question 2 allow to read those DIs at ~100 Hz?
   1. I anticipated using software timed readings. We could read at 100Hz
6. In case you need more (timing) accuracy: could you use hardware-timed AI channels instead of software-timed DI channels?
   1. I am unfamiliar on how to do this again. I thought this would be a reality easy and good opportunity to gain familiarity with Labview, NI products as this is one of my first VIs
7. Why do you stick with feets and miles when there is SI?
   1. I would switch in a heartbeat but that is what our organization uses (generally). I am pro SI.

I really need help just getting the trigger to work for my needs. The rest of the VI I believe I would be able to handle. I know some of your questions are for my exact question however some of them seem like they may be geared towards the overall VI. Thank you

[GerdW]

Hi Gerthex,

so which hardware do you have available?

How do you measure your signals?