Neil's Aventador build (Page 4/74)
RCR APR 13, 07:07 AM
Very impressive on so many levels.



Bob
Neils88 APR 13, 07:27 PM
One thing I forgot to mention with respect to the on board microprocessors...

I also have a 6 DoF (Degree of Freedom) sensor that will be used to give me real time performance data. The sensor is easily connected to any of the Arduino microprocessors (as shown below). The 3D accelerometer will enable me to display 0 to 60 times, braking times & distances, cornering g's, etc, etc. I plan to use one of the two smaller LCD displays on the side of dash display to display these kinds of stats. The sensor also includes a 3 axis gyroscope for even more interesting data. I'll probably set up the system to record the data so that it can be downloaded later so I can view and process the data further. Also will be really handy if I'm ever in an accident...might be able to submit the "blackbox" data as evidence. ...unless of course it was my fault...
Neils88 APR 13, 07:30 PM

quote
Originally posted by kwagner:

Digging your computer/electronics choices. Don't know if I've seen that many in a Fiero before. Looking forward to more




quote
Originally posted by RCR:

Very impressive on so many levels.



Bob



Thank you both!
ltlfrari APR 13, 08:16 PM
I'd be really interested to know how you handle the VSS signal. I've been trying to build a digital speedo since like forever. First with a PIC microprocessor and lately with an Arduino. In both cases I cannot get a clean square wave out of the VSS. I get loads of spurious spikes (even on a seemingly 'clean' signal) that cause additional triggering of the square wave. The result is that the wave period is all over the place making it hard to get any sort of steady signal, even from a stead square wave.

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Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

Neils88 APR 13, 08:46 PM

quote
Originally posted by ltlfrari:

I'd be really interested to know how you handle the VSS signal. I've been trying to build a digital speedo since like forever. First with a PIC microprocessor and lately with an Arduino. In both cases I cannot get a clean square wave out of the VSS. I get loads of spurious spikes (even on a seemingly 'clean' signal) that cause additional triggering of the square wave. The result is that the wave period is all over the place making it hard to get any sort of steady signal, even from a stead square wave.




There are a few ways to do it, but I'll likely have to play around a bit to confirm what works best. I will probably first try using a zero crossing detector. I've also read that you can use the built in comparator in the Arduino. I skimmed some example code for this but it didn't jump out as being intuitive, so it probably won't be my first choice. I know the VSS isn't a nice clean signal, so I will definitely need some good filtering. I'll definitely detail what I end up doing.

Edit: Might also be able to use a FFT (Fast Fourier Transform) algorithm as a last resort...

Edit (2): After a little more research, it's looking like the Arduino comparator will probably be the best way of measuring the frequency. Of course, I can use the processed signal from the ECM rather than raw VSS data since I am using the stock 4.9 ECM. The processed signal is already converted to a square wave. I'll just have to filter the harmonics.

[This message has been edited by Neils88 (edited 04-13-2015).]

ltlfrari APR 14, 10:31 AM
This was the sort of thing I was using to square the VSS signal:



But of course it cannot tell the difference between the regular signal and a spike.

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Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

Neils88 APR 14, 08:31 PM

quote
Originally posted by ltlfrari:

But of course it cannot tell the difference between the regular signal and a spike.




Did you run your signal on a scope? That would have show if your filter was tuned properly.
ltlfrari APR 14, 11:07 PM
I did but I'm no electronics engineer, mostly guesswork and cribbing other peoples circuits although can do digital stuff ok. I just seems to get a lot of spikes from the vss itself and they of course got converted into extra square wave pulses that the Arduino saw and counted.
Anyway, don't want to hijack your thread and I await your solutions with interest!

------------------
Anything I might say is probably worth what you paid for it, so treat it accordingly!

Dave

www.ltlfrari.com

Neils88 APR 19, 12:40 AM
An issue has cropped up with my plans to use my Pico ITX board. I really love the Pico ITX...a computer the size of a deck of cards, capable of running Windows...how can you not like that. Unfortunately, I was getting ready to load a version of my dash program onto it, and suddenly it no longer wanted to boot up. I must have fried it, or maybe the PicoPSU (power supply unit). Cool little power supply. The whole thing actually fits inside the plug-in. Tiny! Cool or not...the PicoITX doesn't want to boot up anymore.



I started playing with installing the dash program onto another computer with nothing but a Windows 7 operating system and discovered that even though I'm just using GDI graphics, I am pushing the limits of the processor and the graphics card (my laptop that I do all my programming on has an i7 processor with a decent GeForce graphics card so it can handle most of what I throw at it....well above the specs of many computers). I suddenly realized that the 1GHz PicoITX would likely not be able to handle the program without running at a really slow frame rate. Anything less than around 15-20 frames per second will look choppy and ruin the visual presentation of the dash. I suspect that the PicoITX is out as an option (I still want to fix mine, because it's a fun system to use...but not the best for this application.) I am now looking at systems that are designed specifically for automotive applications. I will likely switch to a MiniITX system, which has much more power available while still keeping the relatively small profile that I need to fit the unit behind the dash. I'll have my choice of i3 - i7 processors, and a multitude of options. More to follow...

This is the MiniITX case for automotive use...a "car-puter". This is a perfect size for installing behind the dash...
ltlfrari APR 19, 10:28 AM
What graphics packages are you using for the dials etc. I played around with some stuff many years ago but I am no graphics programmer and it was really hard work. I figured there must be a myriad packages to handle all that stuff now.