slicky rick

Brothers... is there any feedback regarding this DIY? I would like to jump into it and have all the necessary parts... I've actually set everything up so I just need to plug in the circuit... but are we sure we won't burn out any ecus or what have you? Thanks bros!!

slicky rick

A final question, is the headlight switch wiring diagram the same for the .1 cars and .2 cars???

Hatzenbach

Yes, it is, with the exception - of course - that 997.2 cars don't have front foglights

slicky rick

Thank you Hatzenbach! And with that, I can finish this project... will let all know how it works... at least now HOME will have a use....

funnelofdoom

hey all, sorry for the slow replies, I've been very busy at work and I keep mocking up new stuff to try. I have a new solution that would only require one module and a photoresistor.

Slicky Rick, did you purchase the parts already? Can you let me know which ones and I'll send you a photo of my v1 setup. I had it running for a few days and it worked fine.

If you want to wait a few more days, I have a new design that would admittedly cost a bit more (about $35) but would be a nearly one box solution. Only requires an additional photoresistor cable and small resistor tied to it. It's much smaller and probably safer since the electroincs are enclosed in a plastic case and it has some internal circuitry that allows for more conventional switching. I can even send you some of the smaller parts you'd need so you don't have to spend so much on small random parts that cost next to nothing in bulk.

kickdown

Again, my two cents. Buy a Cayenne E1 Auto switch - about 25$ from the junkyard and make it as OEM as possible 😎

P/N:7L5941531C

PS: I am not really comfortable with handling circuit boards and soldering. Have you thought about selling the solution?

GC11

I am enjoying reading this thread and your approach to correcting what should have been programmed from the factory, given that all of the hardware is already in place.

I added a cheap circuit years ago to my 987.2 Cayman for a similar effect. It is useful as I regularly use different cars and all of the others have auto headlights.

I have since noted that the tiny ambient light LED contained in the roof light housing only works when the car is on and in the dark. It is positively switched. It is controlled by the existing light sensor in the centre of the dashboard. Alternatively shining a torch or covering the sensor controls the overhead LED’s state.It is instant and not time delayed and ideally it would be tapped into under the dash rather than in the overhead lighting unit.
That may be something to consider.

funnelofdoom

Sorry for the extremely late reply. I have problems with continually including small ridiculous enhancements and the biggest delay was acquiring the VW/Audi/Porsche headlight switch connectors (both male and female) for the switch as I try to use harnesses and don't like to do anything destructive to stock 15 year old wiring. Here are some photos of my slowly evolving solution. I was able to find an off the shelf solution for the timing and sensing circuit and wired up the harness to it. These photos show everything but the light sensor. I will (hopefully) get this thing finally done tomorrow or at least by the end of the week. I will include programming instructions for the programmable timing module and wiring diagrams as they're all hand drawn right now.

The timer module handles pretty much everything including an analog input which allows it to be connected directly to a resistive light sensor with a an additional resistor. Here's a link to the module to the electronically inclined if you can handle this yourself. It allows both a delay on and delay off with a ground sink output to trigger the low beams. This should work with the home function and the diode hack for people who use that, but I haven't tested it fully yet. Will report findings.


I know, this is no longer a $9 solution, but it's pretty cheap still. I had to order a few of those connectors so let me know if you'd like one.





And to kickdown, thanks for making me spend more money on the switch just for the auto text. You know I'm going to have to do it.

Astur

[QUOTE=groovzilla;18968697]When it starts to get dark you turn on the lights. When you turn car off you shut off lights./QUOTE]

FINALLY!... someone with common sense!

funnelofdoom

[QUOTE=Astur;19149642]shoot, I should have thought of that before I started on this project. Thanks for the insight.

jp16061

I've been trying to decipher the 987 wiring diagrams myself after reading this thread. I think I have figured out how to run the linked timer circuit with a photo-resistor trigger. Does this seem similar to yours, funnelofdoom?



The trigger/delay box instructions state: "Do not disconnect the ground from the timer while under power". I'm not sure how this would be an issue though with using pin 2 as ground. I am also not an electrical engineer...

funnelofdoom

Yes that's similar to how I have it wired up with some additional enhancements. The one difference is that I have the green line (the voltage sensor) connected between the resistor and ground. This way, a higher voltage means it will enable the trigger for the lights. It doesn't matter either way though, it's just you have to have different settings.

Another small change is I'm using the rear fog light light (the amber one) on the dial to indicate when the light turns on. This will disable your ability to use the rear fog lights, however, so keep that in mind. I also added a switch to be able to turn the home function off if desired. You just want to connect the home function to the middle of a SPDT switch and put one side to ground and the other to the black wire (of the car harness) which is 12V. Ground is enable home function and 12V is disable home function. I'm attaching my schematics. I made a terrible custom made PCB at home but am thinking of ordering some from PCBWay. They have a 5 order minimum so let me know if you want to do that as well. This avoids a lot of nasty cabling that gets tangled up in the car.

I also have one more pair of connectors if you know how to crimp you can use. It keeps the install looking super clean and you don't have to splice any wires. I used the others for some friends and sent one to Hatzenbach.

Last thing I haven't done yet is use the car sunlight sensor to trigger this. I did some testing and it is a photodiode but unfortunately I'm fairly sure the car is using current sensing to detect the sunlight as there are only two leads. However, I tapped into the unit and put a wire into one side of the diode which will also give us a voltage of 0-5. This way, we can avoid placing a sun sensor altogether and use the same sensor the car uses for the climate control and Home function lights. It's so stupid our car literally has everything needed to do this and they didn't implement it. Literally no additional wires would have been needed, just a couple lines of code.

Maybe the "purists" who love their power seats with their cars but somehow think auto headlights are a huge Porsche sin would have revolted I don't know.



Version that will use rear fog light indicator (screenshot above) to indicate when headlights are triggered on (disables ability to use rear fog lights):



Version that does not use the indicator feature and retains rear fog light function:


You could also just get a SPDT switch to be able to swtich between rear fogs and the indicator. The reason you can't do both is because if you use the indicator light, it will also turn on the actual fog lights. It's possible to do with a module that completely takes over the switching via digital box, but this circuitry will not affect your car's ability to switch on lighting in the event of a module failure.

funnelofdoom

Oh I forgot to add the configuration for the timer. Here are screenshots. If you measure resistance across the resistor as in your diagram, your voltage will be 12V when sunny and 0V when it's pitch dark since the photoresistor resistance goes from 0ohm when bright to many megaohms when dark. I used a 2.2k resistor but mine is reversed and I set my voltage threshold to about 5V. This seems to turn it on when my other cars do. Function 10 allows for a delay when turning on and a delay when turning off. You can adjust the on delay time using t1 and the off delay time using t2.





For your config, you just want to change the analog trigger mode to 2 instead of 1. I believe that triggers when voltage drops below a particular threshold rather than above. Doesn't matter, works either way.

funnelofdoom

Sorry for triple posting. Per a user's suggestion, I also ordered this switch:
https://www.ebay.com/itm/145374865526
because I'm pretty sure I have some type of mental illness. I'll let everyone know if it works, but I'm fairly certain it will.

jp16061

Fantastic. I still don't have my components yet. I did what I assume you did, and ordered a few of the 10-pin VW/Audi/Porsche connectors from Aliexpress with glacial shipping speed. If you want to order a set of PCBs, I'd be willing to split the cost for a couple.

I think I will leave the fog light LED out of my setup, but it is a good idea to have some sort of indicator. Same for the "HOME" function, as I already have mine programmed the way I like with the fog lights through PIWIS.
I also saw the post further up, and my Cayenne switch is in the mail. I cannot wait to have the same tech as my Golf and my wife's Jetta.

Thanks for the programming settings as well. I'll use those as a baseline and tweak to get where I want with the sensor. I ordered a variety pack of resistors after measuring the photoresistor I had on hand. I found a similar size (2k-10k range) would work in my setup. I'm hoping we can get the built-in sensor totally figured out for this, because that would be so clean and simple.

I started by disassembling one of the VW automatic headlight retrofit kits that I had from an old Jetta. It works on a very similar principle, but the VW switch appears to be opposite in that all of the signal pins are ground and it uses the 8th pin as a positive voltage. It even has the same connector and pinout for all of the functions.