Cal3thousand Posted June 1, 2009 Report Share Posted June 1, 2009 So the problem with getting a 98 x70 cluster in my 94 turbo, as we know, is with the speed signal. So what are the options for getting the digital speed signal we all (pre 95ers) want? Here are some ideas, let me know what you think: 1) Swap the whole late 95 - 98 ABS system into my 94? I would be willing to do this; has anyone done this before? What would it require? 2) Get above mentioned ABS computer ONLY and use it to get the speed signal converted into digital. (I think this would be great if we can get it to work). This would require finding out what wires are used in the input/output of the module. 3) AnthonyR mentioned that he accomplished this using an old 850 cluster inline with the NEW cluster to get the speed reading. I have no problem sacrificing my old cluster, but I would need to know what to tap. I would also like to work on paring it down to only the parts needed for this function instead of hiding half a cluster or more in my car. 4) Develop some module that will read the ABS sensor and convert the signal into a useable digital signal. (Technically harder for sure, but could prove to be the cleanest and most reliable). Link to comment Share on other sites More sharing options...
Cal3thousand Posted June 2, 2009 Author Report Share Posted June 2, 2009 Serious? no one? I've seen lots of other threads on here that ended at this point, so I know the interest is out there. Should I go find some teaser images for y'all? Link to comment Share on other sites More sharing options...
Anatoli Posted June 2, 2009 Report Share Posted June 2, 2009 I wanted to have a nice trip computer (and then maybe a nicer cluster) in my 95 855 with Yazaki original cluster. But then I gave up. I do not see the point of this exercise, but it's just my opinion. I think it's easier to get a newer and a more refined car with a nicer cluster. Cheers and good luck on your quest :) Link to comment Share on other sites More sharing options...
Cal3thousand Posted June 2, 2009 Author Report Share Posted June 2, 2009 I wanted to have a nice trip computer (and then maybe a nicer cluster) in my 95 855 with Yazaki original cluster. But then I gave up. I do not see the point of this exercise, but it's just my opinion. I think it's easier to get a newer and a more refined car with a nicer cluster. Cheers and good luck on your quest Sorry, I have a sentimental attachment to my car. Thanks though. Anyone have any ideas as to what is the best option? I'm going to start looking at the wiring for a 96 ABS unit and see if I can just use the output. Link to comment Share on other sites More sharing options...
Anatoli Posted June 2, 2009 Report Share Posted June 2, 2009 Do not take me wrong, i love my car as well, and is not planning to part with it right now. It's just I thought for a moment what would be more fun: a newer looking cluster or a better set of suspension components NP ;) Link to comment Share on other sites More sharing options...
Cal3thousand Posted June 2, 2009 Author Report Share Posted June 2, 2009 Do not take me wrong, i love my car as well, and is not planning to part with it right now. It's just I thought for a moment what would be more fun: a newer looking cluster or a better set of suspension components NP That's why I'm not taking $1000 bucks to a custom shop to get the work done. So, I'm here looking for a cheapass way to get a nicer cluster. I have the cluster, now I need the speedo to work. Now, its time to find a cheap used ABS unit to hack (aster I do some reading) Link to comment Share on other sites More sharing options...
Anatoli Posted June 2, 2009 Report Share Posted June 2, 2009 That's why I'm not taking $1000 bucks to a custom shop to get the work done. So, I'm here looking for a cheapass way to get a nicer cluster. I have the cluster, now I need the speedo to work. Now, its time to find a cheap used ABS unit to hack (aster I do some reading) On a more upbeat note, If you figure something out let me know how it went (PM is great). BTW do you have a Yazaki cluster or a VDO one? Us folks with Yazaki cluster have more trouble getting all the trip info signals and that was exactly what I longed for. Link to comment Share on other sites More sharing options...
Cal3thousand Posted June 2, 2009 Author Report Share Posted June 2, 2009 On a more upbeat note, If you figure something out let me know how it went (PM is great). BTW do you have a Yazaki cluster or a VDO one? Us folks with Yazaki cluster have more trouble getting all the trip info signals and that was exactly what I longed for. I have a 98 s70 cluster that I would like to get into my 94. But need to know how to get a digital speed signal to my cluster. 95+ cars use ABS unit, which I will be exploring. Hopefully someone can confirm that this would be the best path before I take the plunge. Link to comment Share on other sites More sharing options...
Mahi Posted June 2, 2009 Report Share Posted June 2, 2009 I have a 98 s70 cluster that I would like to get into my 94. But need to know how to get a digital speed signal to my cluster. 95+ cars use ABS unit, which I will be exploring. Any specs on the analog signal? Is it a direct Voltage <-> speed correlation or frequency? What does the digital signal on the '98 cluster look like or have to look like? Link to comment Share on other sites More sharing options...
Cal3thousand Posted June 2, 2009 Author Report Share Posted June 2, 2009 Any specs on the analog signal? Is it a direct Voltage <-> speed correlation or frequency? What does the digital signal on the '98 cluster look like or have to look like? From what I have read and can recall, the analog signal is sinusoidal waveform that is induced(?) by the ABS sensors as the wheel rotates. I heard something like 48 cycles per wheel revolution. The digital signal would I guess, be a square waveform. Not sure about frequency translation either. I guess it would be helpful to find out how the ABS unit does it. EDIT: didn't answer your question completely. It uses the frequency, although the voltage is also related (not sure if linear) Link to comment Share on other sites More sharing options...
Mahi Posted June 3, 2009 Report Share Posted June 3, 2009 From what I have read and can recall, the analog signal is sinusoidal waveform that is induced(?) by the ABS sensors as the wheel rotates. I heard something like 48 cycles per wheel revolution. Ok so assuming 48 Cycles/rotation, and lets say you have 17" tires (Model: Bridgestone Potenza RE-11; Spec. Source: Tirerack). There are ~76 inches per rotation on that tire. This will give you ~1.58 inches per cycle. Small amount of frequency counter code is needed and of course the code for the output. If PWM is used on the digital side, there are plenty of micro-controllers that have built in PWM registers, making this more of a case of getting an equation written to go from saying 111.4Hz and calling that 10MPH (using the above numbers). The digital signal would I guess, be a square waveform. Not sure about frequency translation either. I guess it would be helpful to find out how the ABS unit does it. That's a given, I should of phrased that better and asked if it was pulse-width modulation or a data stream, my guess would be the former. This can probably be done easily with a small micro-controller. Most of the Atmel AVR series have analog inputs and PWM outputs. An Arduino would be a good prototype development board to use, they are cheap, have USB, and easy to use (if you know basic C/C++/Java). You may need support circuits to clamp down the voltage from the sensor. A voltage divider circuit would be the cheapest way, but the more legitimate way would using an opto-isolator to protect the micro-controller from being fried. If anyone can post more information on the electrical characteristics of the analog side I can work something up in OrCad. If anyone can get me a waveform of the '94 ABS sensor in action at different speeds that would be awesome, but I doubt anyone even has a digital storage scope, let alone would want it riding shotgun, and I can't borrow one from school. Digital specs. or waveforms would be nice if those who have '97 - '98 vehicles can post them. I would scope my '98 V70 but I do not have it in Rochester. @Cal: If you don't mind waiting till end of July, if people can't post specs. and/or waveforms, I'll see about bringing my big-ass 1980's scope down to Travis's and attempt at getting some readings. Link to comment Share on other sites More sharing options...
Serge Posted June 3, 2009 Report Share Posted June 3, 2009 As Greg put it, any Atmel AVR can pull this off. The cheapest one that has PWM registers is the Attiny13 and will probably be the best in this kind of project. The code to look at an ADC input and then output it as PWM is extremely minimal, literally as little as 10 lines. The trick is figuring out what the differences are between the older and newer signals is. I don't have a frequency counter so that would make it difficult. Link to comment Share on other sites More sharing options...
Mahi Posted June 3, 2009 Report Share Posted June 3, 2009 I don't have a frequency counter so that would make it difficult. Don't need one, just make the analog frontend hardware and use the AVR to spit out the voltage samples or frequency out to serial, and have something like a small C++ app, processing, MATLAB, or LabView make you a waveform or show the frequency count. I doubt we should ever see anything above a few kHz, and the Arduino (which is just a ATMega328 wrapped with a USB controller) runs at 16Mhz. This is enough to sample and send serial at 115.2kbps. Things like this I'd have to imagine are pretty slow and wouldn't expect to see data lines running higher than 500Khz, even 250Khz would probably be high. I'll mess around with the protoboard and get something together tomorrow night. I have some things drawn on the whiteboard now, I'll see how tired from work I am and get some test code fleshed out, debugged, and I'll report back hopefully Thursday or early next week. After the basic front end is built, I just need someone with a '94 in Rochester who feels like being a guinea pig, or an ABS sensor and a wiring diagram. If, BMac happens to be reading this topic, call my cell if you will be around. I'll be in Newtown on Friday late-night till Sunday afternoon. I'll definitely see if I can get a prototype built by Friday before I leave. Link to comment Share on other sites More sharing options...
Cal3thousand Posted June 3, 2009 Author Report Share Posted June 3, 2009 See, I knew someone with the right knowledge would eventually chime in. I never doubt VS Pretty technical talk for the Cosmetic and Detailing section. So much so that it has gone beyond my scope for sure. But I'll help where ever i can. Mahi: I have the complete wiring diagram for a 96 on one of my HDDs... I'll dig it up and send to you in the AM Link to comment Share on other sites More sharing options...
CO.T5M Posted June 3, 2009 Report Share Posted June 3, 2009 get a zazzi cluster from the jy take the gauge faces and switch them over. its looks the same but you dont have to worry about the speed sensor i did this on my 95. Link to comment Share on other sites More sharing options...
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