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Thread: Ipod-CarPc-obd2

  1. #1
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    Ipod-CarPc-obd2

    Hello there everyone....
    can some one please help me and give me some advice....
    My plan is to buy a ipod touch 3g with wifi plus Kiwi Wifi is a plug and play to get the data from the ecu and embed the ipod touch on one of the center console air vents witch measure about the same as the ipod, i will then be using ither dashcommand or REV software to get all the dials displayed real time on the ipod. the reason im going for the ipod is because it has an accelerometer built in. the other thing is that i have all ready a computer in by car with a 7 inch screen and running Centrafuse can i use the computer installed on my car, buy a 3.5 inch usb vga screen or a normal vga connection and some how split the image so i can get the 7 inch screen running centrafuse and run dashcommand pc on the 3.5 inch from the same pc. Now i have ELM 327 v1.2 and when i run digimoto or dashcommand the responce is not acurate and there is a lot of a delay. what obd2 adapter should i get to get leve acurate reading and with no lug in the dials. and also i want the accelerometer on the carpc. is using my carpc too complicated to get what i get on the ipod touch running dashcommand or should i just go with the ipod touch and the Kiwi Wifi is a plug and play.
    ipod touch and the Kiwi Wifi is a plug and play and software is about 350 pound.
    can i get exacly the same thing from my carpc and for less money......
    Sorry if this is a bit confusing but i appreciate some help and advice....

  2. #2
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    I have no idea what you want to do. Try using paragraphs and grouping your thoughts into separate sentences with punctuation. It will make it easier to understand what you want to do.
    Quote Originally Posted by ghettocruzer View Post
    I was gung ho on building a PC [until] just recently. However, between my new phone having internet and GPS and all...and this kit...Im starting to have trouble justfiying it haha.
    Want to:
    -Find out about the new iBug iPad install?
    -Find out about carPC's in just 5 minutes? View the Car PC 101 video

  3. #3
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    Ipod-CarPc-o

    sorry about all the mess....
    have you seen DashDAQ, or ipod running REV software and kiwi wifi obd2? the guages refresh instantaneous and very smooth. i want to know if its possible to achive the same performance with my carpc and a obd2 adapter. my plan is to take apart a ipod touch and put it in one of the center air vents like this http://racediagnostics.com/cms/index...idgolf-options.....
    my question is should i buy the ipod touch and the kiwi wifi adapter witch all will cost around 350 pounds or can i spend less money and use my carpc that i already have installed in the car plus a 3.5 inch vga screen that will go in the air vent....

  4. #4
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    This seems like an incredibly roundabout way to get the information into your CarPC. You're doing this just to get accell data? Speed?

    The primary factor in gauge speed should generally be the speed of the ECU, which varies wildly, unless the interface is utter crap. If you have seen your own interface running on, say, ISO 9141 and are comparing it to another interface hooked to a CAN bus vehicle, you will be sadly disappointed when you drop the money and your gauges still crawl.

    WiFi might sound 'fast', but it actually isn't really any faster than a decent wired hookup. The adapter in my car has both WiFi and USB. WiFi is great for grabbing a log on my iPhone, but I would prefer to use the USB connection for a permanent PC based display. The problem with WiFi is error management. Network errors are inevitable, and things like TCP retry are relatively slow.

    This actually isn't a problem for me, since I use my interface in a 'push' mode. It has a list of PIDs and their priorities, which it polls and then sends to me, so even if there are network errors, my display may stutter, but my logging doesn't slow down and readings aren't lost. But it would be a problem with Dashcommand. Palmer goes direct, packet by packet, so a .5 S TCP retry delay is going to translate to a .5 S gap in any log.

    The last time I checked, the Kiwi used a single SSID and a fixed IP, so 'network errors' would include 'being near another unit in use'. This isn't to bag on the Kiwi, I'm sure it is a fine unit. My primary point is that if you are looking to wireless to make your ECU faster, you are very likely on a path to expensive disappointment.

    -jjf

  5. #5
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    Hi,

    I'm a representative of Palmer Performance Engineering the makers of DashCommand.

    As I understand it you are trying to figure out the least expensive way to acheive your goal of having a 3.5" display OBD-II data in a fancy vitual gauge type way. This screen would be installed in one of your air vents.

    You have stated that you have two options.

    1) Use an iPod Touch + an OBD-II interface that uses Wifi + the software.
    2) Use your existing CarPC + an OBD-II interface + 3.5" vga screen + the software.

    It's fair to say that the software used in each option is going to be about the same price.

    The OBD-II interface choices are numurous. The CarPC can use Wifi, Bluetooth, USB, and serial interfaces. Some can support multiple connection methods, such as USB + Wifi and USB + Bluetooth. Some interfaces also allow you to connect other sensors. The price ranges significantly. The interface for the iPod/iPhone must be Wifi or use a dock port connector. The Wifi interfaces tend to be more expensive than the USB or dock port based interfaces.

    Here are some OBD-II interfaces that are available or have been announced.
    OT-2 from Innovate Motorsports, Wifi + USB + external sensors (jfitzpat can tell you all about it)
    Kiwi Wifi from PLX Devices, Wifi and Wifi + external sensor versions available
    goLink from goPoint Technologies, iPod/iPhone dock connector
    OBDLink from ScanTools.net, USB, USB + BT, and many more.

    So with that, the price of the interface is more or less equivalent for each option.

    That only leaves the price of the iPod Touch to compare to the price of the 3.5" screen. I'll leave that to you but my gut tells me that the price of these items are close too.

    Option 1 is without a doubt possible.
    Option 2 is may also be possible but is dependant on many factors. The OS used on the CarPC must be able to support two screens, the CarPC must be fast enough to run the OBD-II software plus Centrafuse, and then there's the issue of running two touch surfaces simultaneously.

    As for software, I'll speak for DashCommand. It is available for the iPhone/iPod Touch as well as Windows. It does (or will shortly) support all the OBD-II interfaces listed above and more. The Windows version can run full screen on a secondary monitor under Windows 7.

    Assuming that the technical complexity of option 2 can be addressed, it would perform better than the iPod Touch option because of the potentially superior processing power of the CarPC. On the other hand, Option 1 is much less complex.

    Also consider that DashCommand and other software like it can run within Centrafuse, sharing the screen thus saving the cost of a second screen.

    I hope this helps and good luck.

    Pierre.

  6. #6
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    Pierre thank you for your reply...

    the car is a vw golf mk4 1.8t AUM engine. the computer that i have installed is Intel® Desktop Board D945GCLF2/D945GCLF2D with integrated Intel® Atom™ processor running windows 7.... i have a ELM327 v1.2a and i have tried it with dashcommand demo for pc only the rev pid works on the demo and compared to my car rev its about 1.0sec slower. having more pid's showing will slow it down and be very luggy. so i need a obd2 scanner that can have multiple pid's along with dashcommand software and to me as responsive as the actual car dials. i have seen a video of a guy using plx kiwi wifi on a ipod touch running irev software on a vw golf mk4 tdi and its very responsive and acurate

  7. #7
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    Quote Originally Posted by Pierre_at_PPE View Post
    (jfitzpat can tell you all about it)
    God no! Selling the stuff is thankfully not my problem. But I think my main point got missed. The OP seems to be looking for more speed. What I was trying to make clear is that all ECU's and OBD-II physical layers are not alike, and those two factors are huge in things like 'gauge speed' in anyone's software.

    Take a post I wrote about MPG calculation:

    http://www.mp3car.com/vbulletin/engi...ml#post1368900

    That's 16 channels from my daughter's Saturn. And if we zoom in we'll see that we're getting better than 12 Hz update rate on, say RPM. That was interface -> WiFi -> iPhone, then emailed to desktop.

    Yes, the interface is relatively fast. Lots of OBD-II adapters would have trouble replicating that log on the same vehicle. So, it might be natural to say, 'I want that, I need WiFi and an iPod touch...'

    But my point is that gear is only part of the equation, and probably not the most important part here. First of all, it isn't 'WiFi' over serial or USB. I could gave gotten the same trace out of the interface via serial or USB (both of which are on it).

    More importantly, the difference between a 'fast' interface and a 'slow' one probably isn't the difference between usable gauges and unusable ones with DashCommand. I can take my exact same interface from my daughter's Saturn to my wife's Lexus, run the exact same software, and the results are night and day. One is running a CAN bus, the other is ISO 9141.

    I could pull up traces and make a case that I do things to squeak as much speed and usable data as possible from that ISO 9141 link that a lot of interfaces don't. And those things might matter to some users and for some applications. But, in the end, it is a butt slow link, with huge mandatory gaps between things, so if the issue is getting fast gauges on a screen in the car, buying our gear versus a no name scanner on eBay isn't really going to 'solve' it.

    That was my point, unless the OP has seen dramatically better results from that exact make/model vehicle with another tool, it is probably just as well to run your software with the existing interface on the existing head unit, rather than spending a lot of money and not getting the desired results.

    -jjf

    P.S. For others, I've seen DashCommand run on a slow laptop with our HW and can personally attest that 'gauge speed' is not a software problem. I got very good results on my '01 Chevy (J1850), and much slower gauges on wife's Lexus (ISO 9141). It all comes down to the speed of the ECU and which OBD-II physical link is supported.

    P.P.S It is probably worth noting that you can sometimes get faster information out of even vehicles with seemingly slow OBD-II links. For example, I can generally get more information out of a pre-CAN Subu or Mitsu if I force them into SSM or MUT mode than I can using generic OBD-II (which is a slower ISO K line link on both). But that generally requires make/model aware software, not generic OBD-II tools.

  8. #8
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    Quote Originally Posted by dooby_meu View Post
    the car is a vw golf mk4 1.8t AUM engine...

    i have seen a video of a guy using plx kiwi wifi on a ipod touch running irev software on a vw golf mk4 tdi and its very responsive and acurate
    FWIW, it depends on model years. Off the top of my head, I think an MK4 AUM could be something like MY '97 to '06. The vast majority of them are ISO 9141, which is very slow.

    A TDI could easily be model year '05 or '06, which would generally run the newer CAN ECU, which is dramatically faster.

    As I noted above, I have personally seen Dashcommand provide fast guages, provided only that the ECU gives prompt data.

    -jjf

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    dooby_meu: You are concerned that the sampling rate of your existing OBD-II scanner (ELM3277 v1.2a) will be too slow based on your experience with the demo of DashCommand.

    As jjf has pointed out, sampling rate is mostly limited by the vehicle's ECU. Therefore the first thing you should do is test for the sampling rate and if it's good then you will know for sure that you can proceed with any of your plans.

    Here's what you need to do... Use DashCommand's Data Logging feature to capture a log of SAE.RPM then send me the log and I'll be able to tell you what your sampling rate is going to be on your car. The whole procedure should only take 5 minutes.

    Steps:
    1) Launch DashCommand and press connect
    2) Press Data Logging
    3) Remove all the PIDs in the list except for SAE.RPM (use the Remove PID button)
    4) Start logging by pressing Options then pressing Start data logging.
    5) After approx. 30 seconds, press Options again then press Stop data logging - you'll see a splash saying the log has been saved.
    6) To export the log by pressing Options > Log File Management and selecting the last log in the list then pressing Export.

    When you have a log file send me a PM and I'll give intructions on how to get it to me. Or you can try to attach it to a post.

    I just did the same proceedure using an Innovate Motorsports OT-2 connected to a CAN ECU simulator and got an average sampling rate of 39 samples/second (Hz). Impressive.

  10. #10
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    Quote Originally Posted by Pierre_at_PPE View Post
    I just did the same proceedure using an Innovate Motorsports OT-2 connected to a CAN ECU simulator and got an average sampling rate of 39 samples/second (Hz). Impressive.
    Actually, I would have expected even faster, but even with CAN it can depend on the ECU. Some take a lot more of the maximum allowed time to respond than others.

    I'll try to get ahold of my daughter's car again and test, clearly I was getting a lot better than 40 Hz in that previous log. On the other hand, some ECU's, like a latter model GTO, are CAN, but not all that fast in terms of responsiveness.

    -jjf

    P.S. In the small world department, I used your SCAN XL software with an OT-2 last night to find the bad wheel sensor causing the brake light on my Chevy.

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