Tony

what he said. I mean there is a sense of uniformity when you get in ANY car no matter what the model year. From year to year, designs do change but things remain uniform with in the design year....fabrics...coverings..*****...fonts...graphics. The closer you get to a Porsche...928 specific appearance the better.

928er

one thing that has to be considered in addition to the texture and design of the ***** is the thickness. The entire console area will now be flat with no other *****. If the ***** are to tall the they will stand out too much.

Rob Edwards

Hans-

My bad, the bushing is actually hard clear plastic, molded into the surrounding rubber stuff. Not stretchy. No spring clip either, just a flat spot to mate to the flat spot on the shaft. Yell if you'd like any measurements to consider.

hans14914

Cant really consider them since they wont work with the encoder shafts natively. However, there is no reason why people couldnt modify them to work on their own. Seems to me like you could find a .25" bushing, drill out the old core, glue in the bushing, and then pour epoxy or a resin around the bushing. Shouldnt be too hard for a 2-piece operation, but I am really not interested in making a batch here. I think my time and efforts are better spent on other portions of this and other projects

Thanks for looking into it.

Hans

Alan

I believe it does fit a standard shaft - I have used these in this config before on standard 0.25" shaft (see prev pic - Post 745) - I did not modify these for that application.

But I have also modified one with new center bushing & set screw to fit a round 0.125" shaft much as Hans describes.

I do think these will work for this and I think flatter ***** would be a mistake - the rear AC ***** for example are not good ergonomically IMO (and are way too big in diameter for this application too). These seem similar to what Hans proposed in size.

I'd say these could be just a do it yourself adaptation for those who want a more stock looking **** - since there is still some customization to do on these for the markings. I think I'd want to use these for sure - but I'd also be happy to do it myself

Alan

Rob Edwards

At the risk of being the one-too-many chef that spoils the soup, a little digging from Hans' pictured ***** brings us to the specs page for those *****:

http://search.digikey.com/scripts/Dk...90+BLK&x=0&y=0

Those that have 0.250" shaft bushings are .925" in diameter and .625" tall, close to the fader ***** size. A bit smaller and taller, but close.

Anyway, Hans has gotta move forward in spite of all of our best efforts to mire him in details. The good news is that the core system is going to be bewilderingly customizeable- I can't wait to see what people come up with once the system is released out into the wild.

hans14914

Thanks Rob. The other benefit on those ***** is that they are surprisingly affordable... especially the knurled version. It wont add much to the overall cost, so you wont feel bad replacing them with that factory **** latter on.

If someone wants to send me a stock ****, I will take a look at it, but I think that the knurled **** will be the standard option. I am not sure how dependent I want to be on the porsche supply chain... we already exhausted the global supply of window switch frames when we did that project. Lesson learned.

Thanks
Hans

blown 87

That will be great, but please tell me you are going to use the black *****.

hans14914

It will be the customers choice. I will stock both designs in both colors.

blown 87

Great, I just had to find one thing to bitch about on this project.

borland

Hans,

Does the Climate Control's LEDs and display dim with the dash light dimmer switch, or does it have a function to dim them separately?

hans14914

Borland,

all the LEDs in the display tie to a transistor before going to ground... so they are globally dimmable.

The base is connected to the micro-controller, and it will be able to be coded to dim under several parameters. I do have an analog pin on the controller with a voltage divider which monitors the illumination circuit. I have not tested that portion yet, but i designed it with the intent that the LED dim in relation to the voltage on the illumination pin (either scaled or via lookup table).

So hopefully they will dim in tandem with the light dimmer pot.

Thanks
Hans

hans14914

The first revision of the final climate interface (if that makes any sense) was a reasonable success. There are some design modifications which are still required. I have made those changes, and will be sending out for another batch of test boards soon. The LCD display is up and running, as is the dual plane power supply, and the LED indicators and general purpose outputs... so all the difficult stuff is up and running.

Before I send out that order, I am working on revising the control board. I think that by going SMD for both boards, that I should be able to "backpack" the two boards for certain applications (they will still be separable to connect via a ribbon cable). I have gone back and found suitable SMD replacements for the components, and changed a couple things out.

There is now a dual 5v power supply, one to power the board and all the supplementary electronics - which will be connected to switched +12v, and then a second which powers the microcontroller and will require a constant +12v feed. This second regulator has extremely low current consumption, which allows the micro-controller to be powered at all times. It simplifies certain internal routines in the code and with the power supply design, now that it doenst need to store information in non-volatile memory about all the settings as often. It will monitor a pin which will be attached to the +12v switched supply via an optocoupler. Thus when the optocoupler is firing, it knows the car is on, and to poll the communications busses and engage the peripherals. When the opto is dead, it knows the car is off, so it can write all the current settings into NV memory and then just wait until the opto comes back up signalling ignition.

I also changed the way the AC is triggered and sensed. Pin7 on the climate card-edge connector is for the AC switch input from the button on the console. Starting in 91, Porsche used this pin not only as an input, but also as an output. With the 91+ cars, the off position is actually a recirculation position which engages the AC. The climate control unit can turn on the AC on its own, and does this in the demist mode on all cars, however, it does not have control over the main cooling fans. When you press the AC button, the fans come on to cool the condenser. on the 91+ cars, the climate control backfeeds Pin7 in that special off/recirculation mode, causing the fans to run as if the AC button was pressed.... pretty clever.

This current revision does the same thing, to simplify the AC button delete for those who choose to do so, or those implementing with the revised console. Using the same optocoupler technique for the power sense system, there is an identical circuit to monitor voltage on Pin7. If there is no voltage on Pin7 and the AC mode is engaged, it will supply +12v on Pin7 internally. Thus the AC will operate as intended either with or without the external AC button.

So that was a bunch of boring information that you probably could have lived without. The reason I started posting tonight was because I am watching the component cost total... and it is getting up there. I am at the point now where I have well over $100 in components. There are certain things I can cut out of the design to lower the price, without effecting the way it functions. For example, I have $7.20 worth of TVS diodes that help protect the micocontroller. The microcontroller itself costs around $30 for the version with the full USB header on it. It is installed in a socket, so if it was damaged, it could be swapped out. So, is it worth $7.20 to protect a socketed $30 part? You guys tell me.

On the same subject of protection, I can put fuses on the circuit board to protect the AC relay and the control unit itself. However, if one of these fuses goes out, it will require pulling the head unit to access it. Again, your guys opinion, do you want that extra layer of protection knowing that if it needs to be serviced, you would have to pull the head unit out?

We are down to final design details, so trying to get some feedback before buttoning this up.

There are things I can do, like include jumper pins to bypass a fuse holder, which I may do giving these options after the fact. Similarly, I can put the pads for the TVS Diode array on the board, but dont have to populate them with components. However including all those features adds significantly to board layout time, so if they are definitely not needed/wanted I can omit them completely.

Thanks
Hans

borland

Hans,

Can you consider adding a delay feature, such that when the car ignition is switched to OFF, that the heater valve vacuum solenoid is still left active for at least 15 minutes?

That would help eliminate the 'Blast Of Hot Air' upon warm restart that's considered a summer annoyance with these cars.

jeff spahn

I'll chime in here. I vote for spending 7.20 for protecting a $30 part. Also, any extra protection is better in my opinion to protect the main parts.
I vote for the best design. If it costs an extra $50, who cares.