Confused Newbie

**MattJackson86** · 06-14-2006, 11:58 PM

Hi all,

First off I would like to say that I have read many of the posts on here and googled much of this.

I am really confused as to what is needed to read data from the OBD II Connector. I know that I need to connect my pc to the car. but how? Do i use one of these cables with OBD on one end and serial on the other? or do i use one of the box things that has obd and serial.

This is what I have been looking at:
http://www.multiplex-engineering.com/products.htm
http://www.ecufix.com/shop/index.php...roducts_id=198
http://www.mp3car.com/store/product_...roducts_id=192

I like the look of the ElmScan 5. Is this good?

....and many of the others.

But what is the "right" one. I am wanting to right my own app that will pull info from the OBD. Either 1 bit of info (speed) or multiple. I understand that the more your pull the slower the connection. Anyone have any good tips on programming this? (I am an experianced programmer)

So mainly I am just confused as what to buy. I would like something that can read MOSTprotocalls and probably serial connection not USB. (I think it would be easier to program)

Please Help!

Thanks

**Sidewalksalvage** · 06-15-2006, 12:14 AM

Well, i personally havent done this hook up yet (and with an 87 camry i kinda cant) but from what i know....

There is a converter from the OBDII to a serial connection.
There are many out there and i even read about one that i believe was USB.

Most that i have seen come with their own software for monitoring purposes. Also, if you check out the front end section, i have seen some who have integrated it into their set up. One had road runner displaying a speedometer and tach.

This probably wasnt much help, but i do know there are MANY on this site who have done it. You may want to check out the front end section for programming tips.

Good luck.

**joeyoravec** · 06-15-2006, 10:02 AM

Originally Posted by CityFan86

I am really confused as to what is needed to read data from the OBD II Connector. I know that I need to connect my pc to the car. but how? Do i use one of these cables with OBD on one end and serial on the other? or do i use one of the box things that has obd and serial.

Because your PC uses one set of protocols (usb, serial, ethernet, etc.) and your Vehicle knows a different set of protocols (CAN, J1850, ISO9141, etc.) you need to use some sort of "gateway". There are several boxes/cables available on the market. Be sure to look for SAE J2534 compliance -- the standard for PC-to-Vehicle PassThru vehicle interfaces

Originally Posted by CityFan86

I like the look of the ElmScan 5. Is this good?

But what is the "right" one. I am wanting to right my own app that will pull info from the OBD. Either 1 bit of info (speed) or multiple. I understand that the more your pull the slower the connection. Anyone have any good tips on programming this? (I am an experianced programmer)

Although the ElmScan5 was popular with hobbyists in the past, it is completely proprietary. Now with PassThru cables like Mongoose available for $200, the ElmScan no longer seems competitive. You can check out my comments in another thread. Will the proprietary junk (elm5) be supported once inexpensive, standard cables dominate the market? Doubtful.

If you're programming your own software, I'd recommend starting with a standard PassThru cable like Mongoose. What makes this standard? The driver DLL provides functions to connect, read, write, and apply message filters so you're not locked into one vendor's equipment! The hardware manufacturer provides a driver that takes implements all the low-level details.

Originally Posted by CityFan86

So mainly I am just confused as what to buy. I would like something that can read MOSTprotocalls and probably serial connection not USB. (I think it would be easier to program)

Personally I wouldn't obsess about needing an all-in-one adapter. If you only have one car, it's better to do one protocol well than 4 protocols crappy (and never use 3 of them).

Also remember that you should use functions in the device driver to make your life easy -- there's no reason to fumble around with the low-level USB, serial, or Ethernet code.

**MattJackson86** · 06-15-2006, 10:53 AM

Thank you for all the info. I am much clearer on my options. I like the look of that mongoose cable, and you make a good point about using the provided driver.

Thank you again.

**blazerdude** · 06-19-2006, 08:57 PM

The ELM327 based products are the most flexible and have the most features, a bunch of different software packages, and work on every obd2 protocol, including CAN. I have an obd2allinone unit and it's great. There is a USB and a serial version available and comes with a software CD, see:
http://www.obd2allinone.com

The unit is solidly built and quite compact, shipping was fast, and it seems to be the lowest cost of the ELM327 units out there. It works with many software packages, with a bunch of free ones. See:
http://scantool.imechatronics.com/downloads.htm

Read the ELM327 datasheet and it tells you all the ELM instructions so you can write your own program if you want.... that's why there are so many good programs out there for it.

**digimotojoel** · 06-19-2006, 09:33 PM

One of the main reasons ELM became so popular was definitely because of the way they allowed programmers to easily interface through serial communication... it is really one of the most simple interfaces to integrate with ~ small startups wrote software for it and pushed the market on the ELM even further. Another reason was simply because of the price tag... pre-CAN interface, you could get an ELM322,323,320 interface for $70, you could build your own for around $50. Now that the price has gone up, so does a persons expectations of the hardware and the quality of software that comes with a piece of hardware. Higher end tools like the one sold by AutoEnginuity (although the interface is proprietery... even more so then ELM), offer better software options. Your best bet is to first pick the software you like, and then the interface which is sold with it ~ make sure it provides the functionality you are looking for.. something quick and dirty, something to allow you to program your ECU or perhaps something strictly diagnostic, but includes manufacturer specific codes designed just for you vehicle. Hardware is nothing but a hunk of junk without the right software.

If you are looking to build your own software, I would recommend you definitely take a look at the ELM or BR3 or mOByDic interfaces (pick one, basic concepts are there) ~ I have never used the mongoose although I had an opportunity to at one point... so I can not say what my opinions are on that hardware. There is a reason that coders around the world have picked these common interfaces to develop against... maybe perhaps becuase they were the only ones available?

. There is a company called Multiplex Engineering which sells hardware which would allow you to tie your interface to your software ~ it is the interface that AutoEnginuity chose to go with. Many options, pick up an old ELM interface on eBay for $30 and start to play around, pick up some books and educate... then decide.

**joeyoravec** · 06-19-2006, 10:12 PM

Originally Posted by blazerdude

The ELM327 based products are the most flexible and have the most features...

You must be kidding. No programming voltage, no J2534 driver. It uses an ASCII based wire protocol, and since there's no driver DLL everybody must reinvent the wheel. It uses a 9600 or 38.4k baud host interface. There's a tiny buffer and one hardware message filter, only for CAN, so don't plan on full bandwidth with other protocols or communicate with more than one CAN physical address. Also ignore the bugs in ELM327 v1.0 like parser case sensitivity and protocol locking.

Originally Posted by blazerdude

Read the ELM327 datasheet and it tells you all the ELM instructions so you can write your own program if you want.... that's why there are so many good programs out there for it.

Good programs? Half the programs on that iMechatronics list have red checkmarks to indicate incompatibility with ELM327. Search the forums for opinions on the other software including Digimoto. Notice one great package on that list PCMScan which supports PassThru (J2534) hardware like Mongoose. All the ELM327 stuff is looking pretty old and dusty in comparison.

Yes.... If you're going to program OBD-II, then read the ELM327 datasheet for a laugh. Then read about the PassThru API which provides functions to connect, init, read, write, filter, send periodic messages, and turn on programming voltages. No need to do the serial/usb grunt work, just program your OBD-II application.

**digimotojoel** · 06-19-2006, 11:36 PM

Joey, we hear the sales pitch loud and clear ~ the only tools you are going to pitch are your own, I have been completely unbiased. I hate to burst you bubble, but the Mongoose is not the only logical option out there. Some people want something extremely simple ~ nothing overly complex... some people want something low budget... you can't be in the high and and low end market, you just wont understand things from up there

. There is a reason the ELM interface was so extremely, and continues to be, popular. I don't even sell the hardware anymore and I can tell you that I would purchase the ELM in a heartbeat over the Mongoose... simply because I get it, and so do a half a million other people out there. The only feedback I get is on my shipping delays ~ however, on a more positive note, I'm not the only one talking about what I sell on the forums

. Do a quick search for mongoose and I'd be surprised if anyones name but yours comes up.

The concept of pass through technology is a good one Joey! Seriously, I believe the fundamentals are there... it's just that development houses like Digimoto are low budget solutions. There is a reason even PCMScan, the only software developed to support the Mongoose does not even sell it... but they sell the ELM.

If you can knock a few bucks off your unit I think you would find more reception to the interface. Try to keep an open mind Joey ~ I have a bit of history with your company and I see through the biased opinions.

You have a unique perspective Joey, because you do know your hardware... and you really truly seem to believe in the J2534 standard. From a developers standpoint and even from a consumers, we have to justify the pros and cons of what a piece of hardware has to offer. As an OBDII solution, strictly as an OBDII based tool, the Mongoose is one of the highest priced DIY interfaces out there (not even including what the software would cost). You charge $200 for a single interface (it is not even a multiprotocol unit) ~ to get all the functionality you would have to purchase around $800 in mongoose hardware compared to the $100-130 for a multiple protocol interface like ELM or mOByDic. If an app like Digimoto were to integrate the J2534 standard and build a solution to support the Mongoose, we would have to utilize features above and beyond the OBDII capabilities your unit has to offer. It is not quite in reach, but perhaps down the road a bit.

**droptop_stang** · 06-20-2006, 01:15 AM

Just to add to the post, I personally have used and am currently using on of the ELM based tools. The software is user friendly and it does exactly what I wanted it for in the first place, to scan trouble codes. As for using the tool to turn off the check engine light, it works great, I did that for my girlfriend in her car...it hasn't been on since. Also scanned our other OBD II vehicles to see that there were no codes or even any pending codes. If you are looking for a scanner, then maybe check out the company I got mine from at www.myscantool.com (They were on sale I think). The one I bought was the universal kit and it works great. Just thought I could maybe be of some help in your decision.

**Headsex** · 06-20-2006, 09:30 AM

Its simple..
If you want a Toy, get the ELM

If you want the real deal, get the mongoose...

Personally, I use Cardaq's, and I love j2534 much like joey does.. So its the mongoose for me thanks

Dan