HalfInchWrench

I'd like to build one but can't decide what would be best. Looked at the links to schematics from this site but do they all work equally as well? The 2 transistor looks easiest of all. Does that work? I would first like to be able to scan my 87 GTA. Can always build something more elaborate later.


I've been using Autotap since 99 or so. Never ever dealt with ODB I so it's time to get my feet wet. I am long overdue. Later I would like to build a programmer but I would like to learn about stock paramaters first.

gta324

I have used both 2-trans and MAX 232 with both ECM852 and TTS and both worked ..

Build the 2-trans and download ECM852 from www.moates.net and start from there........

/N.

HalfInchWrench

I'll have to try the simple one then. I have a few Max232's and a few other pieces left around from other projects but not enough to complete. I wish there was an elect. supply place close by. I have to drive for a half hour for a couple of dollars worth of parts. Too little of a parts list to avoid shipping charges from digikey and the like too. Damn.


Is anybody aware of any dangers in using the simple design? Some of the other projects I have tried, many of the hardcore electronics guys didn't like the "easy" interface without a Max232. Anyone have any opinions on that? I'm not a EE or anything like that. I can follow schematics, solder, use a meter ect but I am not good enough to look at a design of a circut and say yes it will work but could damage something.

327_TPI_77_Maro

iTrader: (8)

My little 2 transistor cable uses a series resistor to step battery voltage down to ~5 V. It doesn't even use a voltage reg. ! This scares me. I am going to modify it to add a little 5v reg I got from radio shack. The cable does work excellent though. I've logged for an hour with no bad packets at all.

HalfInchWrench

I had a feeling something like that would crop up. Have you figured out how to incorporate the regulator into the circut? When you do could you report back no matter if it works or not?

Thanks.

327_TPI_77_Maro

iTrader: (8)

Adding the voltage regulator is super easy. It has 3 pins - Input, output, ground. It will no doubt work, and be guaranteed more stable than relying on the car's electrical system to provide clean power.

HalfInchWrench

I'm not that much worried about clean power from the car. It should be fairly clean shouldn't it? Not like AC from the house shared with everybody in your hood. More worried about isolating the car circut from the notebook circut. I think that is the bigger risk. I may be wrong tho. I don't care much about the notebook, would hate to fry the car ECM.

Come on, I'm sure there are some hard core electronics peope here, please speak up.

JohnnyIROC-Z

I jsut put a 10K resistor from pin 2 to pin 4 and used the laptop com port to power itself.