Traction Control System with MoTec M400

[peedpeed]

Hello everyone!
I'm new here. Now I have my project to install TC system to my formula car, which is equipped with MoTec M400 ECU.

The wheel speed sensors that I'm using receive "pulse" signals but MoTec M400 ECU receives signals in "square wave" forms.

So now I'm looking for a "pulse" to "square" converter in order to convert the signal so the ECU could work.

I'm looking for any of you guys' advice. Thank you.

[Ben K]

We run the M400 as well and might be looking into TC in the near future. Where are you from?

What do you mean exactly by a pulse signal?

Either way you probably could set up a flip flop type switch that could kick on for a certain amount of time, then turn off based on a 555 timer. Sounds like a fun PCB project.

Ben

[peedpeed]

Hello, Ben

I'm from Chulalongkorn University, Thailand

And I've used wheel speed sensors which are magnetic pickups (I think they are the same as abs sensors) to measure the wheel speed and send it to ECU. These abs sensors seem to send the signal as a "pulse" as an output. But for M400, which TC is included in the ECU, seems to receive a signal to operate in a "square wave" forms.

So first I'm thinking about some converter to change the signal into square wave before sending it to ECU.

I just skimmed through some other discussions about TC system. And I'm not sure that maybe there is a "hall sensor" that can measure speed and send the signal out in square wave forms.

PPP

[theStig]

By pulse do you mean PWM (Pulse width modulation?) Technically PWM is a square wave. Does the M400 measure based off of square wave frequency or the pulse width of a square wave?

[Ockham]

peedpeed, I assume that when you say "pulse signals," you mean that your wheel speed sensors are variable reluctance. If their wave form looks like this...

h t t p://forums.pelicanparts.com/uploads11/Waveform1194366968.jpg

...then they're VR sensors. If you use a Hall effect sensor, which outputs a near-perfect square wave, you can save yourself the trouble of designing a conversion board. Check out the Honeywell GT101, available from DigiKey. Not sure about shipping to Thailand, but here's a link to the site.

h t t p://search.digikey.com/scripts/DkSearch/dksus.dll?lang=en&site=US&WT.z_homepage_link=hp_go_button&KeyWords=Honeywell+GT1&x=0&y=0

[Vassili Wang]

I agree with Oakham.Perhaps it is a question about "Hall" and "Magnetic".

[Crispy]

I think that is the same Honeywell sensor we used last year for our wheel speeds, and we implemented traction control with an M400 without any special signal conditioning.

[peedpeed]

Just another question, is a hall effect sensor the same as a vehicle sensor used in commercial cars; Honda Jazz, Honda Civic, Toyota? Because I have been looking for a second-hand sensor part of these car, which is easier to find here in Thailand.

Anyway, thank you guys for all of your advice. This helps me a lot.

[Vassili Wang]

To peedpeed:

How about using industry sensor instead of vehicle sensor? I think industry sensors are widely used everywhere.

[peedpeed]

I looked through the link that Ockham gave me and found out that Honeywell GT1 seems to be my solution but I am worried about the delay of ordering and shipment.

So I have to look for an industry sensor which is a hall effect sensor (similar to Honeywell GT1), right?

PPP

[Nicky]

Motec sells the GT101. They take about a week to ship in Asia. I reckon that you use an inductive type sensor for the packages available are quite small. The GT101 is fairly large and requires a bigger tooth dimension.

Here's the Datasheet (http://www.motec.com.au/filedownload.php/?docid=1309).

regards,
Nikhil

[Ockham]

Motec sells the GT101. They take about a week to ship in Asia. I reckon that you use an inductive type sensor for the packages available are quite small. The GT101 is fairly large and requires a bigger tooth dimension.
Most teams have been shaving those dimensions for years. We've successfully tested different sensor orientations and wheel thicknesses (down to ~2mm). Hook it up to an oscilloscope and power supply, with the test trigger wheel on a lathe head, hold the GT101 near the sensor (carefully!) and see if the signal's strong. You can use bolt heads or brake rotor slots as trigger wheel teeth with clever packaging.

[Boffin]

Depending on how many auxiliary outputs you aren't using, you can get around this without constructing anything.

Input the wheel signal into motec and as an auxiliary input.
Then drive an auxiliary output that switch's between on and off (aux table, 0, 1) depending on what voltage you are seeing.
Then connect this auxiliary output into the digital input on the m400, and you should have a square wave.

Only problem could be the refresh rate of the aux tables/outputs. It may not be fast enough.

This kind of thing works fine though. It's how I've got our thermo fans wired up, so I can get two comparisons for it (eng temp and RPM), instead of just one (eng temp). Haven't has a problem yet.