This should be an easy one for those who do such things....
I'm currently trying to gather the bits together to fit an Electric Power Steering column off a Vauxhall Agila/Suzuki Wagon R to my kit. To get the speed sensitive bit to work, the EPAS ECU needs to see a pulsed signal ov 0-1v and 9-12v. I'm fitting an electronic sender to my type 9 but it gives a pulsed 0v to 5v. Will 5v be enough to satisfy the EPAS ECU or will it want the whole 9v+? What gizmo can I use to step the pulse from 5v to over 9?
Cheers chaps and chappesses.

Before you even get to the signal level (which is fairly easy to correct), are you sure the pulse frequency (i.e. pulses per mile) of the Ford sender is remotely similar to that used in the Vauxhall?

I would say a single transistor stage should do it, something like the typical BC108 4K7 from your 0 to 5 Volt signal to the base of the transistor put a 4K7 from the collector to 12 volt and take off at the collector to the steering input.
Base current around 1 mA
Collector current around 3 mA but depends on what the steering input requires?
The Emitter grounded.


The single transistor will invert the signals in that 5 Volt will become 0 Volt and 0 volts in will become 12 Volt or 13.8 Volts depending.

I would also add a few 1nF caps around to provide a bit of filtering of spikes.

Do you know if there is a maximum input to the steering controller or not?

Last point is the output from the type 9 sensor actually 0 to 5 volt Square or is it a sine wave output?

Edit for small change.

Adrian

[Edited on 16-7-12 by AdrianH]

quote:

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Originally posted by owelly
This should be an easy one for those who do such things....
I'm currently trying to gather the bits together to fit an Electric Power Steering column off a Vauxhall Agila/Suzuki Wagon R to my kit. To get the speed sensitive bit to work, the EPAS ECU needs to see a pulsed signal ov 0-1v and 9-12v. I'm fitting an electronic sender to my type 9 but it gives a pulsed 0v to 5v. Will 5v be enough to satisfy the EPAS ECU or will it want the whole 9v+? What gizmo can I use to step the pulse from 5v to over 9?
Cheers chaps and chappesses.

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I read that as 0 to 1 Volt was low input and 9 to 12 Volt high level input!

3 to 9 volts a bit indeterminate as in logic levels. I am correct in this or as above two inputs needed?

Adrian

Here, have a looksy at these numbers for the EPAS ECU...


I read it as the speed signal is pulsed from below 1v to over 9v. Not two separate inputs.

I have no idea if the Ford and Suzuki (don't go confusing things as the Vauxhall corsa stuff uses a completely different system!) use the same pulses per revolution. I was just going to try it and see what happens! I know the Ford sender pulses 8 times per revolution, as measured with my multi-meter. I can soon find out how many revolutions occur per revolution of the propshaft. I just need to find a willing Wagon R to try the same stunt.

I'll busking most of this to make use of the column I have without resorting to using it with the manaully variable, but non-speed sensitive system that other folks are using.
Thanks for the help so far.

ETA the VSS is the vehicle speed sensor...

[Edited on 16/7/12 by owelly]

To convert a 5v high signal into a 12v high signal I would use a single rail comparator fed the signal into one arm and 3v into the other and run on 9v. Simples. As long as it's square wave. Otherwise you'ld need an op-amp in multiplier mode.

Few more bits simple fag packet style

fag packet style

Probably a couple of £'s parts from Maplin.

Get 250mW resisters apart from the 39 Ohm which is 0.6 watt.

The Zener is 1.3 Watt.
Electrolytic Cap typical 10uF 25 Volt working.
BC108.

there is a few depends, like the VSS must go below 0.6 Volt and go up to 5 Volt square wave. The current in the steering input must be negligable, (the 4K7 collecotr load can always be reduced a bit.

Sort of thing I might knock up as a will it work type of thing.

Yes a voltage comparator with a pot on the level trigger would be better, I will see if there are any simple kits or ready made boards.

Adrian

Excellent reply! Many thanks. I can just about manage to blob solder onto a board so I may have a trip to Maplins this week.

Might be easier in the long run?
Corsa B C - Electric power steering controller box - With ECU plug - EPAS RALLY | eBay

Would there ba an easy way to convert the pulses per rev from the sensor? Just in case the signal from the Ford do-hickey tells the ECU the car's doing 120mph at walking pace?

quote:

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Might be easier in the long run?Corsa B C - Electric power steering controller box - With ECU plug - EPAS RALLY | eBay

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I have also found a voltage comparator style circuit using an op amp at Maplins.

it would need a bit of a change but could give a variable switching point. It is their Thermostat kit.

A Velleman kit circuit found here http://www.velleman.eu/downloads/0/minikits/manuals/manual_mk138.pdf

Maplins part number RR51F.

Changes would be to remove C3 and put a couple of nF cap in instead.

Do not go between the NTC pins but input across R4 Would still like to see a resister in line. No relay use a 470 Ohm 0.6 Watt resister instead and still go out from the collector. The two diodes and 1K resister also removed.

Adrian

To alter the number of pulses would need a sort of counter circuit.

I have to ask but is this needed on the kit, I have thought about adding one when doing the Autosolos, but found I can cope quite well.


Taking me 3 edit's to say what I mean, bed time for me.


[Edited on 16-7-12 by AdrianH]

Thanks again. You've lost me a bit with your explanation but I'll figure it out after a bit of sleep!
My car has very heavy steering. The quick rack doesn't help. I can improve it by pumping up the front tyres but then it just understeers. So I run the fronts at 16psi. I'm keen to keep the speed sensitive bit to keep some feel at higher speeds.
Rallywiz have started making a controller kit for the Agila EPAS but, again, you lose the speed sensitive bit.

ETA. Here's a clip of my chum hustling the car round some cones. It takes two hands to turn the wheel with such effort, that the stitches have pulled out of the steering wheel!
http://m.youtube.com/watch?v=zIO9G388sRo

[Edited on 16/7/12 by owelly]

And this site for Corsa and others

Rally wiz

quote:

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Originally posted by owelly
Would there ba an easy way to convert the pulses per rev from the sensor? Just in case the signal from the Ford do-hickey tells the ECU the car's doing 120mph at walking pace?

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Snapper, see post above yours. I'm trying to keep the speed sensitive bit....
I think I'll just do the 5v to 12v thing first and see how far away the calibration is. I'm guessing that at a standstill, there will be maximum assistance which gets less as the road speed increases. That works for slow speed manouvering so it'll do for a start!
Cheers again guys.

A bit more digging suggests that Ford electronic speedo drives are 8 pluses per revolution which aims to be 8000 revs per mile. I can soon confirm that once I get the speedo sender in my Type 9. I just need to find out what the WagonR speedo uses.

Most VSS signals are straight from the wheel speed sensor typically using 24 to 32 teeth 0 to 1v about 20,000 to 40,000 pulses per mile

But the VSS on the Agila/Wagon R is on the gearbox and appears to be a two wire jobby that simply grounds the output from the ECU.
It looks like I'll have to buy a Wagon R to find out......

ETA, the VSS is a three wire unit, not two. It has a 12v supply, a wire through the loom to ground and the signal wire to the EPAS ECU.

[Edited on 18/7/12 by owelly]

VSS in gearbox, thus....

I have found a list from an American company that supplies aftermarket cruise control systems, that gives pulses per mile. It suggests that almost all Fords use 8000 pulses/mile and that Vauxhall/Suzuki use 4000pulses/mile.
I'll see how my set-up is looking with my 13" wheels and 3.62:1 diff!

if its a two wire sensor on the box then it will need to be converted to a digital signal either through the speedo head like saab/gm systems or in the ecu itself with a converter . check the agila wiring diagram to see if the vss signal goes to the clocks or direct to the ecu

It goes direct to the EPAS ECU by what I can tell by the wiring diagram.