VSS Signal assistance?

[ac7ss]

well, If the pulses are unsteady at a constant speed, then the problem is mechanical, as mentioned before. a well lubricated speedo shaft could help, or find another source for the signal.

(The only thing I had at work to see the waveform with was "Windows Media Player")

[dcb]

ac7, I used a way old copy of cooledit. dunno if it still exists.

forgotten, if the changing the vss enable event timing doesn't fix it then I would ask that you set it back to 2ms and then drive with the wonky speed reading and see if distance tracking is still ok at those speeds.

I just took a road test with the stock .72 codebase. Didn't have any issues at 75mph. I didn't have a spot I was comfortable going faster than that within reasonable driving distance. At some speed the pulses WILL be less than the debounce period but I expected it to at least get folks to 80mph @2ms.

[forgottenmindset]

Originally Posted by dcb

ac7, I used a way old copy of cooledit. dunno if it still exists.

forgotten, if the changing the vss enable event timing doesn't fix it then I would ask that you set it back to 2ms and then drive with the wonky speed reading and see if distance tracking is still ok at those speeds.

I just took a road test with the stock .72 codebase. Didn't have any issues at 75mph. I didn't have a spot I was comfortable going faster than that within reasonable driving distance. At some speed the pulses WILL be less than the debounce period but I expected it to at least get folks to 80mph @2ms.

Hey there,

My vss code is 32816 (8204*4) and it's very very accurate now that i changed it to 1 milisec. Much better, but at 60 mph the vss reading starts slowing down just like it used to at 40 mph. Sometimes I do go faster than 60 and it messes up, is there anyway I can go lower than 1 milisec?

Also, quick question. I tried creating a timer a while back, and it was only accurate within a half a second, is that just the nature of the clock on the board or my code? If my code, I think I can fix it.

[dcb]

Let me have you try one more thing, I think you are chasing noise with that 32k number.

change your vsspulsesPerMile to 4104
and change the addEvent line to
addEvent(enableVSSID,4 )

and report your findings. (how does the speed signal look, how accurate is the distance over a few miles of driving)



re:timer, please leave it out while we are troubleshooting, ensure you have a fresh copy of .72 loaded.

[forgottenmindset]

Didn't work, just made things more wacky

Now the speed reading is about 4 times higher than it should be up to about 25mph then it just starts counting backwards again

[dcb]

Did it effect the distance tracking?

You can also try:
32832 vsspulses per mile.
and
change:
addEvent(enableVSSID,2 ); //check back in a couple milli
to:
enableVSS()


but I'm flying blind here, would need to see the waveform at a given speed and get an answer to the "is distance affected?" question.

[forgottenmindset]

Hey now I'd be back where I started if I put that all back in!

addEvent(vssid, 1) works well (super accurate) with the 32 number except when I get past 60 mph

with 2 miliseconds it works well up to about 40 mph then counts backwards

I need to get it under 1 millisecond, but mabey that's not possible?

I do all kinds of driving, I'd really want it to be accurate up to at least 120 mph

Mabey mark (with the mitsubishi) will let me use his scope since we're both local
Didn't he have a battery powered one?

edit:

I didnt check if the distance tracking with those other numbers was accurate but I'll try that like you said. However, distance tracking IS VERY effective with 1 miliseconds up till 60mph

[dcb]

Originally Posted by forgottenmindset

Hey now I'd be back where I started if I put that all back in!...
I need to get it under 1 millisecond, but mabey that's not possible?

I just said how to do it

change:
addEvent(enableVSSID,2 ); //check back in a couple milli
to:
enableVSS()


this will call enableVSS immediately instead of 2ms later (or 1 or whatever you currently have in the second parameter).

[forgottenmindset]

bwaa! delete, delete

I didn't even read that part

I'm such a dummy, ok I'll try that

[forgottenmindset]

Yes, works good like it

but not perfect

If I got it on a scope could we get it perfect?