Reading pulses from ABS wheels speed sensor

Using Arduino Project Guidance
1

I am trying to figure out how to get a signal from my front wheel speed sensor.

I believe it is a hall sensor, but may be wrong.

I attached a diagram for it. It is a 2005 Corvette

I want to count the pulses to get distance.
It has 2 wires going into it.
one has about 4.8v when it is unplugged from the sensor and the other has 0v
When I plug it up, both wires have about 2.3v no matter if I am spinning the wheel or not.
I was expecting it to drop and go back up as the wheel turned.
I tried hooking my meter to both wires while plugged in and I got .136v and then when I turn the wheel it would fluctuate .12x-.14x, but nothing I could call a pulse.

Thanks in advance for any help

WSS.gif
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2

I got some advise from another forum and was told it was a change in resistance that the car uses to read the passing of a lug on the relucter.

3

Hi,
Yes they are a reluctance type, they output a pulse as a tooth on the wheel goes past.
Caution, as the speed increases usually the output amplitude increases as well so may get over 5V.

Tom.... :slight_smile:

4

Look into the NCV1124 IC. I used one of these to read the ABS sensors from a '94 Vette, but I am not sure if the later Vettes have the same output..

This IC takes the SIN wave produced by the ABS sensor and converts it to a rectangular wave form which is easier to read with the Arduino. I used the pulseIn() function to read the output from the IC.

Charles

5

Thanks. I think the newer ones should produce a square wave.

6

Hey @brandonppr, I've done this before. I built a project a while back and had to use the vehicle speed sensor. What is the year and model of your vehicle? On my Toyota minivan, I found the wire in a large packet of wires under the driver's side dash, behind the steering wheel. Of course, I didn't just "find" it. Do a search for "vss wire" or "vehicle speed sensor wire" and your year, make, and model.

I sent the wire straight into the Arduino and used an interrupt to trigger the pulse counter. Make sure to ground your Arduino to the car, or it won't work.

Here's some info at a taxi supply website: http://ielectron.ca/index.php?route=information/information&information_id=12

I've got lots of other good info from failing many times on my own project, so feel free to ask :slight_smile:

7

Just a work of caution.

Make sure you do not load the signal or cause any change to what the control system reads. You do not want to change the control with possible accident and void insurance.

Weedpharma