ABS sensor output for speed based boost

[Speedeuphoria]

Does anyone know the output of the abs sensor signal, I have read this(look at fig 1.4, and 1.5) It isn't dodge but I would think they are mostly similar
http://www.picotech.com/auto/tutoria...actuators.html

I was looking for an easy way to get a signal similar to the sds(speed distance sensor) or tach signal from a rear wheel to use speed based boost control. My Eboost2 needs a square wave signal switching from 0V to 3.5-12V.

looking at the pic above the "rss" or sds in dodge terms has the square wave, but the ABS is AC voltage sine wave. Can anyone confirm this for the dodge sensors?(abs and sds)

Then I found this info also:

The ABS sensor acts as a small AC generator. The sensor consists of a small permanent magnet with a lot of turns of fine copper wire around it. As the 'teeth' of the ABS reluctor ring pass by, they cut the lines of magnetic flux from the sensor magnet. This in turn causes an AC voltage to be generated in the sensor wire.
Ideally borrow a 'scope to look at the AC output from each sensor as you spin each wheel. The waveform will be approximately sinusiodal. AC voltage is proportional to rate-of-change of flux variation and therefore will *increase* as wheel speed increases - the frequency of the AC will also increase of course (this is what the ECU is looking at).

So I'm not so sure it would work, hopefully it would be OK since the frequency is what they both prodouce/read, but not sure if I do like 150MPH it will burn up my EBoost2 with too much power?

I was thinking since I already have 11" vented R/T brakes all around that I could just pickup an ABS rear hub and sensor to swap since they were available with ABS, then wire it to the rpm input on the Eboost2. Since the sensors aren't cheap I am trying to see if this is a feasible option or if I need to make something different. The sds does work but if the wheel spins it compounds the prob by ramping boost up(so doing a burnout would keep raising boost), hence the reason for using a rear wheel for the speed signal.

[glhs875]

NOW your on to something! If you get this idea figured out, it will be AWESOME!

[Speedeuphoria]

hey I just edited it, was hoping you would see it.

I guess an easy test for the not so smart people like myself would be to just hook up a tach to an ABS sensor/car and see if it works or causes any issues, any car should work as they seem to be the same. Someone want to do this please!?

Basically the concern is difference for the square wave and the AC sine wave outputs, and how high the AC voltage goes max.

This will work with any EBC that can do boost by RPM's using the stock sds sensor, and also if this ABS signal turns out to be compatible

[Speedeuphoria]

well I dont think this is going to work, but still down for someone hooking a tach to the ABS sensor to test. I guess the next best thing would be to use the ABS hub and mount a proxy sensor to it. Then you may have to grind off some of the teeth so it reads right, or mount a small magnet(s) to the hub and use the proxy

[glhs875]

When I have a little more time to spare I'll look into this more. Right now I use MSD RPM switches triggered by the speed sensor and then on to solenoid bleeds for staged boost. The speed sensor puts out what is the equivalent to a 4cyl tach signal. But I don't know what wave it is in. I've never looked into wave forms. If a magnetic pickup of some sort was mounted to pick up the ABS teeth on the rotor I would think that might work. A speed sensor makes it's own voltage when it pulses. May just have to get the pulse count compatible to the controller. I was going to look into a rear wheel boost control output after I get my clunker going again. Because reading off the rear wheel will be way more accurate and better than off the front wheels. Wheel spin messes with my setup somewhat.

[Speedeuphoria]

OK Frank or Brian I know you guys are good with electronics(and others). I heard that i may be able to put a diode on the ABS signal to convert it from AC to DC voltage and should read like a 6-8cyl tach output. I'm not good with electronics or diodes so can anyone shed some light on this?

[Anonymous_User]

Yes, you could use a diode to rectify the AC sine to a DC signal. I'd like to see a scope of the signal. Then a proper rectifier could be designed.

A prox switch on the ABS hub would work also. All of the DC prox's we have here at work are 24v. I'm sure there are 12v prox's out there somewhere. But, given the environment you are asking them to survive in......

Edit: Just checked out your link and there's the scoped output of the ABS sensor. You can use a single diode to eliminate all the -V, or you could use four diodes in a bridge to change the -V to +V. For the application you are wanting to use, I think a single diode would be best so that you get fewer pulses and they are more pronounced.

[Speedeuphoria]

Yes, you could use a diode to rectify the AC sine to a DC signal. I'd like to see a scope of the signal. Then a proper rectifier could be designed.

A prox switch on the ABS hub would work also. All of the DC prox's we have here at work are 24v. I'm sure there are 12v prox's out there somewhere. But, given the environment you are asking them to survive in......

Edit: Just checked out your link and there's the scoped output of the ABS sensor. You can use a single diode to eliminate all the -V, or you could use four diodes in a bridge to change the -V to +V. For the application you are wanting to use, I think a single diode would be best so that you get fewer pulses and they are more pronounced.

Thanks for the reply, I guess that is going to be the easy 1st step to try, I have also found that you can convert AC sine wave to DC square wave(well its not perfect but close), heres is the info on the circuit needed(which confuses me at this point but I will be looking more into it)
http://forum.allaboutcircuits.com/sh...54&postcount=2

[t3rse]

I had considered making a ghetto traction control by looking at the wheel speed difference front and rear using a cheap bicycle speedo on the rear. The speed/distance sensor can be used to determine front wheel speed, so look at the differential between the front and rear tire acceleration rates.

[glhs875]

Yes, a diode will remove one of the alternating waves of the current output and make it compatible with DC current. Alternators on vehicles have didodes in them for that very thing. And if your worried about excess voltage output, you could also install a proper voltage diode from the output wire to ground to bleed off the excess voltage to ground. Now I'll be honest, changing wave forms is above my head, at least at the moment.

[glhs875]

I looked at the graphs. What I would be looking at doing, is figuring out a way to install a speed sensor on a rear wheel instead of using an ABS sensor. As the speed sensor aleady has the output signal your looking for. I work at O' Reilly's, if you want I'll be doing some research on the available speed sesors, and maybe find something that will be easily adapted to a rear wheel.

[Speedeuphoria]

I looked at the graphs. What I would be looking at doing, is figuring out a way to install a speed sensor on a rear wheel instead of using an ABS sensor. As the speed sensor aleady has the output signal your looking for. I work at O' Reilly's, if you want I'll be doing some research on the available speed sesors, and maybe find something that will be easily adapted to a rear wheel.

That would be great, I've found more info and a couple are helping me on that allcircuits site. I had one question for you what is the minimum speed you have tried, meaning when the signal it showed up. This is a problem since the ABS increases voltage and frequency by speed, this shows very low voltage at 10MPH
http://www.picotech.com/auto/article...osing-abs.html

It seems the SDS just increases frequency while keeping the voltage waves constant. Also I though my sds was just 2 wires signal and ground, so I dont where it gets the voltage(spedo works though).

The ABS parts are not cheap so maybe just using a ABS backing plate and mounting the magnet and proxy in the hole(or another sds) would be better.

[glhs875]

Using my MAC multi-meter, the stock speed sensor can be read immediately. As little as 10mph is no problem. I would definitely be looking at using the ABS bracket and wheel but with a speed sensor electrical pickup of some sort. Some tuning of the tooth count of the ABS wheel may be required to get the pulses into range. I'm thinking less pulses would equal being able to read at less MPH. I know with the stock sensor, I'm using the 4cyl mode on the MSD switches. That seems to work great, as I can alter the boost in 1st gear (slow vehicle speed).

[glhs875]

What I would do is figure out how many pulses per revolution a stock speed sensor has, and then duplicate that number on the rear which results in a 4cyl tach signal.

[Speedeuphoria]

Well looks like the thread title should be changed because of a number of factors involved. Now moving on to the original idea from GLHS875 and finding something that will mount on the rear for the signal.

here is some more info I've came across about sensors and the difference between 2 and 3 wires

Hall effects(3 wire) need a voltage input of usually around 5v. What ever your sensors input voltage is, just don't go over it. Hall effect sensor's output voltage doesn't vary with frequency. For a magnetic reluctance sensor(2 wire), the current and voltage that is induced is dependent on the strength of magnetic field and the frequency.

I found a couple ~$30 halleffect sensors that say they are for ABS, speedometer, transmission speed or Wheel speed, they look like automotive sensors. I dont have specifics on the output or the sensing range but both will run off 5v to 24v. They both require an external pull up resistor.
http://www.cherrycorp.com/english/se...007_Series.pdf

http://www.cherrycorp.com/english/se...012_Series.pdf

i was looking for a cylinder shaped one, but with out looking at the hub again , I dot know whats best.

These were also recommended to my, they are cheap ~$10 but not sure about mounting
http://www.allegromicro.com/en/Produ...ensors/ats.asp

[87csx2.4]

What I would be looking at doing, is figuring out a way to install a speed sensor on a rear wheel instead of using an ABS sensor

Hey you guys Im not really up on all this but I do know my a guy that has done this with a proximity switch.Dont ask me how because I don't know but I may be able to find out.Brian knows who Im talking about it's chad's electrical engineer buddy.

[Aries_Turbo]

just saw this thread now.....

a schmitt (or maybe schmidt or something like that) trigger is a chip that cleans up sloppy pulses and makes them nice and sharp. you could use that to make the waveform a square wave.

an opamp (LM324 maybe) can be used to buffer the low output of the abs sensor at low speeds. set it up as a comparator circuit with a fairly low trigger voltage. i have a schematic of a comparator circuit in mpboost's thread in the SRT section.

you can use that circuits transistor output to drive a schmitt trigger and from there to the boost control.

youd need to measure the abs sensor voltage output to see what it is and if its going to be too high for the op amp. probably need a diode to ensure that the waveform is positive in nature.

Brian