Distance from speed and time?

[faior]

Yeah, what the title says.. Ive been trying to make some script which gives you this.. without success :/

Problem is, that it starts to minus things when speed starts to go down from the max reached. And this gives the readings like 1 kilometres -> 1.2 kilometres -> 1.1 -> 1.3 -> 1.0 etc.

Could someone give some example script maybe? Or is this even possible?

[Weston@PPE]

Could you please post this script? I would like to see what you tried to do.

It seems like it would be possible. The accuracy would depend on how often a new frame was recorded (because speed changes).

Here is what I threw together. Let me know if it works. In this script I am assuming that the script name was SCRIPT.DISTANCE. If you don't name it this, you will have to edit some parts of the script.


function GetRequiredPids()
{
   Obdii.AddRequiredPid("SAE.VSS");
}

var Speed = Obdii.GetPidValueEnglish("SAE.VSS");
var TotalDistance = 0.0;
var PrevDistance = Obdii.GetPidValueEnglish("SCRIPT.DISTANCE", Obdii.CurrentFrame - 1);

if(PrevDistance != null)
   TotalDistance = PrevDistance;

// We have our last distance travelled, and the speed. Calculate the time and distance traveled since then.
var LastTime = Obdii.GetPidTimeStamp("SCRIPT.DISTANCE", Obdii.CurrentFrame - 1);
var CurrentTime = Obdii.GetCurrentTime();

var TimeDiff = (CurrentTime - LastTime) / 1000; // Convert to Seconds.
Speed = Speed / 60 / 60; // Get Distance per Second

/* Hours / 60 = Minutes; Minutes / 60 = Seconds */

TotalDistance += TimeDiff * Speed;

Obdii.PidValue.English = TotalDistance;
Obdii.PidValue.Metric = TotalDistance * 1.609344; // Miles converted to Kilometers

[faior]

Ahh! That works like a charm, thank you very much!

I think my script didnt work because of the missing "+=" thingy, I did have about the same code that yours is, except that. And I did have the problem too that it added too much to the total distance, because I just "distance + distance" instead of using totaldistance += speed * time.

But this is useful, thanks again.

[Weston@PPE]

What I did was calculate the miles per second traveled, and multiplied it by the time since the last calculation.

That same line could have been written like this:
TotalDistance = TotalDistance + TimeDiff * Speed

Or, you could even do this:
var DistanceDiff = TimeDiff * Speed;
TotalDistance += DistanceDiff; // (Or TotalDistance = TotalDistance + DistanceDiff;)

+= is just a shorthand way of adding something to a number.

[archangele]

How do you bundle this into a script?

[Pierre@PPE]

Hi.

To bundle this into a script do the following...

From the main menu of ScanXL, select Tools > Script Editor.
Press the New Script button
Press the Edit Script button
Copy the script test from the post above and past it into the Script Editor window (the bottom part) overwriting the example code.
Change the name to SCRIPT.DISTANCE and save.

That's the basics of it.