VAG-COM Adapter: Ulf's Worst-Case Version 4.0

Hello everyone,
Okay, I'm going to try implementing Ulf's circuit diagram with the KL/KK switching option. Can someone please confirm the following parts list?

Please provide the German text you would like me to translate into English.
Optocouplers.
3 x PC 817

Trimmers.
3 x 10,000 Ohms, 1/4W.

Diode.
1 x 1 N 4002
16x 1 N 4148

Widerstand (nach mgl. Metal, 1/4W, 1% tolerance.
1 x 10 Ohm
2 x 100 Ohms.
3 x 330 Ohms.
1 x 470 Ohm
6 x 1,000 Ohms
1 x 1,500 Ohms.
4 x 3,300 Ohms
1 x 15,000 Ohms
1 x 22,000 Ohms.
1 x 56,000 Ohms
1 x 68,000 Ohms

Transistor.
5 x BC 547 C

LED.
5 x LED

Capacitor (ceramic)
1 x 1 nF
2 x 10 nF
2 x 47 nF

Capacitor (Electrolytic capacitor)
1 x 47 µF
1 x 220 µF

Voltage regulator.
1 x 78L05

Switch.
1 x A/B switch.
Please provide the German text you would like me to translate into English.

If I haven't miscalculated anything on the circuit diagram, that should be it.

Can this be achieved using a breadboard and "wiring," or are there simpler PCB options available?

Does anyone have any other tips?

Thank you!

Tino Kossmann wrote:

Does anyone have any other tips?

Hi Tino,

I haven't completely counted through your list - you should be able to figure out the arrangement correctly on your own (don't you have a parts bin where you can find a replacement for a missing component?).

"So far, I've mostly used these IC experiment boards (available from companies like Conrad)."
The optos go in the center, and everything else kind of goes around them.

However, you probably won't be able to fit the entire 4.0 version onto such a board. Instead, you could use a (perforated) breakout board with jumper wires to accommodate the components that don't fit on the main board.

Unfortunately, I don't have a "junk box" – I might have a few individual diodes or resistors lying around, but by the time I find (and identify) them, I could just order a few new ones for a few cents.

I'm going to try to implement it on a breadboard using "point-to-point" wiring... hopefully I won't forget any wire crossings.

Hi Tino,

Here are two more tips, just in case:

Order at least one spare part for each (not too expensive) item.
It's really annoying when, for example, you burn out a transistor during the first test, and you have to order a replacement part individually, including shipping, and then wait for half a week .

Solder the C5 capacitor as close as possible (using short traces/wires) to the 78L05, so that the latter is as reliable as possible and does not start oscillating.

Sorry to have to ask again:

In the circuit diagram, there are 5 LEDs shown, with "LED 4" appearing twice. I suspect that one of them is supposed to be labeled as "LED 5", or something like that?

What functions do the individual LEDs have, so that I can choose the corresponding colors?

Are the standard 2.x volts / 20mA (e.g., Conrad 184900) sufficient, or do I need to use actual 12-volt LEDs?

Hi Tino,

Yes, yes, the numbering .

LED 1 = Laptop initiates car charging.
LED 2 = Laptop calls the car.
LED 3 and 4 (at the bottom) = Car responds (separately for both K-lines).
LED 4 (top) is lit at full brightness = The adapter has sufficient operating voltage.

Use standard LEDs (approximately 20 mA / 2 Volts). The current-limiting resistors for the 12V supply are already included in the adapter circuit.