Any possibility to use VR sensors as wheel speed inputs?

[PeepPaadam]

Since most cars have VR sensors for ABS, is it possible to use those? As I understand it requires additional circuitry (possibly with LM1815 or the like?).

[rob@vems.co.uk]

No reason why you couldn't make up a seperate LM1815 circuit and feed that into the keyboard input that Sambas is using for wheel speed input.

Rob

[PeepPaadam]

I have a small problem: I don't know how to make that circuit  It would be awesome if anyone could draw a schematic or something and I could try it? Presuming it won't be helluva complicated which would defeat the purpose (i.e. vs installing a separate HALL sensor somewhere in the drivetrain).

[Sprockets]

Just one thing, what is the intention for this data?  Purely datalogging?  If so, rob is right.  There is a non official firmware (if any of them actually ARE official lol) to do this which you will have to be mailed as I think it isn't public domain.

As for the circuit, a generic LM1815 isn't difficult to construct using a DIP part and a handful of discrete parts on some breadboard.  There are examples in the datasheet, but I am not saying to much more as I would only be giving bad info.

There is a lot of info about on this somewhere.  Either here or the dreaded wiki.  I remember reading about it.

Good luck with whatever you end up doing!

-Gavin

*EDIT*  See what happens when I type about stuff I have no idea about.  The firmware is in the software forum, samabas has it in the 1.1.47 experimental link, and looks like MWFire has it working...... I'm gonna top up on coffee!  Sorry for the mis information! */EDIT*

[PeepPaadam]

Yeah, I'm aware with the PS2 input otpion but it only accepts the square wave HALL signal, not VR sensor. I'd like to make some circuit that let's me condition VR signal to square wave signal.

On a race-car wheel speed input is very beneficial and let's you see wheel-spin and corner speeds in turns.

[Sprockets]

OK, I see now.  Give me a bit, I have a basic LM1815 circuit here somewhere that will do what you want.  I was using it for a little side project.  Lemme see if i can put it on a seperate page for ya.

-Gavin

*EDIT* http://www.filehosting.org/file/details/10884/oaWwL3PapK9b9zHF/LM1815_1.PDF  That is a basic circuit which should do what you need.  You may need to play with the R values a bit as this was designed to read from a slightly differnt source, and sorry about the scruffy layout, was literally ripped from a design I'm still tidying */EDIT*

[MWfire]

Yes, you can use VR sensor from abs. But abs sensor(on my car) has to many impulses per 1 rotate of wheel. So you will need diveder(like CD4040 or many othre). Find out have many pulses give abs per wheel rotate and i will draw schematic.
Here is log from my car(without turbo for now:(

[PeepPaadam]

*EDIT* http://www.filehosting.org/file/details/10884/oaWwL3PapK9b9zHF/LM1815_1.PDF  That is a basic circuit which should do what you need.  You may need to play with the R values a bit as this was designed to read from a slightly differnt source, and sorry about the scruffy layout, was literally ripped from a design I'm still tidying */EDIT*

I can't download it, it gives me error message saying I have to request new download code??

MWfire, my car has only three slots for speed sensor but my friends 911 Carrera has 42 IIRC.

[MWfire]

I will make schematic. Here is example of speedsonsor(road was wet:(
http://www.vems.hu/files/DamirMuha/1.1.47/speedsensor/datalog200901291852.xls
And i will try to make new vems.ini for speed sensor(gear) boost settings.

[MWfire]

Values in brackets are pin numbers for ps/2 connector


This is basically VR input divided by 8. Maximum pulses for vems at 100km/h is 255 per 1 second.

[gunni]

Great a working design.

I would now like to see this for sale in the webshop or something.
Maybe as little box with PS2 connectors on both sides?

[MWfire]

I didn't try thise design yet, but i think it works.

[PeepPaadam]

THANK YOU!!!

I'll try to convince my friend to make a PCB desing for it in Eagle or the like soon.