Schematics from the WinALDL site, modified to add an LED (I like blinky lights ).
Step one, clean the board with a Scotchbrite and then wipe it down with acetone:
Then start laying out solder pads for ALDL terminals. Turns out that a plain old Sharpie permanent marker has enough plastic solids in it to use as an etch resist pen, for a fraction of the price that Rat Shack charges:
Finished the artwork:
Cut the board out to size:
Pour in the trusty ferric chloride from Rat Shack:
Add two resistors and a green LED to the board end, then connect the cable (old mouse cord):
All done:
Tried it out, works like a champ:
Sharp eyed readers will note the extra terminal, that is for future use when I build an ALDL cable to interface with the 8192 baud ECMs used in the 87-88 DIS Fieros.
Hope y'all found this entertaining!
JazzMan
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10:31 PM
Gordo Member
Posts: 2981 From: East Guilford, NY, USA Registered: Mar 2002
that is pretty awesome...i need to learn how to make some simple boards like that...very cool once again.
-Coop
It's really much easier than it looks. I've made much more complicated boards as well, using tricks like laserprinting the circuit design onto a peeled sheet of laser labels (the backing is heat resistant) then ironing the toner onto the copper board. The toner is plastic, so it acts as an etch-resist. As you can see from my images, low-tech is definitely easy to do. BTW, this whole project cost me less than $5, and if I could get the boards mass-produced would probably run less than $10 to build.
JazzMan
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11:57 PM
Jul 5th, 2003
2Fast_Fiero Member
Posts: 1106 From: Tijeras, NM USA Registered: Jul 2003
i guess im the slow one of the bunch, but how does that work? what does it do? i don't get how sticking that in reads the codes. only way i knew of was grounding it and watching the blinking light, or a code reader, does this replace a code reader? and if so what do you plug it into? cool project though, i need to learn about sometime
Oops! I forgot to mention what this cable does. It is for connecting my laptop to my ECM's ALDL connector. I run WinALDL on my laptop, and it displays on the laptop the info that the ECM sends out via the ALDL connector.
A brief description of the ALDL is in order. ALDL stands for Assembly Line Diagnostic Link, and was used on the assembly line to make sure the engine was working properly. The connector is located under the plate that holds the cigarette lighter in place. There are two ways to use the ALDL. One way is to short the mode terminal to ground. This causes the ECM to flash any stored trouble codes on the Check Engine Light (CEL) when the key is in RUN and the engine is off. Turning on the engine with the terminal grounded causes the ECM to flash the CEL on for rich and off for lean, so you can watch the flashing and get a feel for what the ECM is seeing from the O2 sensor.
The second way to use the ALDL is to hook a scan tool to it, or in my case a laptop set up as a scan tool using software. Now, to use a laptop (or PC for that matter) you have to covert the voltage signal from the ALDL connector to one that can be understood by the laptop's serial port hardware. That's where the 2N2222 transister and 10K Ohm resister in the interface end of my cable come into play. The WinALDL software site has the schematic that I used. Once you convert the voltage, then you have to tell the ECM to send data to the terminal in the ALDL connector. You do that by putting a 10K Ohm resistor across the mode and ground terminals (the ones you shorted to get the codes on the CEL before). That's what one of the resistors does on the board that I made. The other resistor on the board simply drops the 12 volts of the data terminal down for the green LED I use as an activity indicator. The LED is not needed for the interface to work, I just like blinky lights.
If you click on the link for instructions for building an interface cable you get two schematics. I built the one powered off of the DTR pin, and modified it by putting the 10K mode resistor on the board instead of in the connector backshell, and added the blinky light. Did I mention that I like blinky lights?
If anyone wants more help on building any aspect of this cable, let me know and I'll see if I can get more detailed pics and instructions posted.
What kind of board did you start with... something from Rat Shack?
Just a generic piece of single-sided .06" board I had laying around in my junk pile. It may have come from Rat Shack, or it may have come from a garage sale.
I wouldn't recommend using .03" board as it may be a little flimsy, plus it's harder to get unless you happen to have some laying around.
JazzMan
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09:37 PM
Jul 7th, 2003
GOLDSE Member
Posts: 388 From: St. Louis, MO, US Registered: Apr 2001
What you need to do is cut the cord about 3" from the aldl board. Then solder on a headphone female plug. Drill a small hole, mount it in the cig. bezel. Solder the male connector on the other end, and voila, now you don't have to remove the cig. bezel each time...
------------------ --1986 SE V6, Wild Custom Notchback --1984 SE Modified Notchback
What purpose does the blinky light serve? Just a visible indicator to know the cable works? Or does it blink the code?
It actually blinks on and off with the data stream. I don't really use it for anything but eye candy, but it would come in handy for diagnosing why the interface might not be working by showing whether data was present or not.
What you need to do is cut the cord about 3" from the aldl board. Then solder on a headphone female plug. Drill a small hole, mount it in the cig. bezel. Solder the male connector on the other end, and voila, now you don't have to remove the cig. bezel each time...
I saw Jeffry's cable and jack arrangment a while back. I don't like drilling holes in my car, but in any case I haven't bothered putting the lighter plate back in since I finished overhauling my engine last August.
Also, I've got several cars, so the drill approach would mean fabricating many more boards.
BTW, nice Libretto. Around here those still sell for over $300-400, which for a 486 is just plain stupid. That's why I won't get one. If I can find someone to help me with my Newton 2k I'd like to create a version of WinALDL for it.
JazzMan
(someday I'll learn myself how to speel) [This message has been edited by JazzMan (edited 07-08-2003).]
[This message has been edited by JazzMan (edited 07-09-2003).]
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01:07 AM
FieroLT1 Member
Posts: 320 From: MilwauKee, Wisconsin, USA Registered: Nov 2000
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