18 hours since pour. Mylar with release conditioner sprayed on it… works well to easily release resin cast (from wood mold.)

http://forums.pelicanparts.com/uploa...1477571851.jpg


Mylar panel that was glued to inside of mold. Glossy area is where resin made contact with it.

http://forums.pelicanparts.com/uploa...1477571893.jpg


Air-side shrinkage on bottom of panel. Very little on top. What appear as cracks in resin is casting from mylar’s deformation when it got wet from pour.

http://forums.pelicanparts.com/uploa...1477572069.jpg Bottom

http://forums.pelicanparts.com/uploa...1477572080.jpg Top


Facia mold is removed. Decision to make window mold for display screen was good choice---bottom line = would have taken much more time to cut & finish this window, then Dremel-form display’s mounting ledges compared to making this window mold.

http://forums.pelicanparts.com/uploa...1477572206.jpg


Thickness of casting is to give these side walls some strength. Fiberglass is embedded all around.

http://forums.pelicanparts.com/uploa...1477572260.jpg

http://forums.pelicanparts.com/uploa...1477572293.jpg


John's working with Nextion display so seeing how it fits will wait until he’s done programming & testing system. Would like to think I can add and subtract---equally well as MONSTERon---but one never knows. Display might fit (with no mods...) Might not! Window for screen is offset in face panel to the left to compensate for display screen being offset to the right.

http://forums.pelicanparts.com/uploa...1477573202.jpg


.

3d printed abs can be finished the same as any other plastic, prime and paint.

This entire tail section is 3d printed, primed, and painted.

http://forums.pelicanparts.com/uploa...1477576113.jpg

^^^ J... yeah, 3d and CNC were options here. Technically that would surly have been more precise than my monkeybusiness... but not as much entertainment as working with silicone putty, resin, molds, etc. (Part of the gratification in all this is to make-by-hand. Know this is not everyone's cup of tea. Exploring materials & methods is my addiction... coffee I can do without.)

That's the way you do it!

https://i.ytimg.com/vi/lAD6Obi7Cag/hqdefault.jpg

^^^ http://forums.pelicanparts.com/support/smileys/wat6.gif

Trimming existing AC knob panel's top and side edges so leather has space to wrap to back.

http://forums.pelicanparts.com/uploa...1477586722.jpg


0.032” aluminum cover. Will fill old through-holes with epoxy. Then redrill to fit switches. Center cut-out where speaker control was... how about a button. Text below button reads: Passenger Eject

http://forums.pelicanparts.com/uploa...1477586943.jpg

http://forums.pelicanparts.com/uploa...1477586786.jpg

http://forums.pelicanparts.com/uploa...1477586900.jpg


Am sorting out now how to connect display panel to AC knob panel. Either wood block or aluminum “L” with epoxy & screws. Front-to-back brace at bottom of unit is probably in order to prevent display from snapping away from knob panel at some rough handling point.

http://forums.pelicanparts.com/uploa...1477587052.jpg


There's slight bevel at entry to cubby. Missed this when original opening dimensions were taken. Is easy adjustment.

http://forums.pelicanparts.com/uploa...1477587068.jpg

Used to be front-to-rear fader switch---for audio control---between AC control knobs. That roller is now removed. Plan is to move FAN and TEMP knobs closer to each other to visually compensate for deleted roller... but am now rethinking that choice. Alternative path is to move knobs farther apart and install on|off switches between. Won't use these switches for anything immediately but would rather do this sooner than later. (Alternative switch location is below display. Would be slightly farther reach.)

http://forums.pelicanparts.com/uploa...1477670880.jpg


RR3402A

http://forums.pelicanparts.com/uploa...1477670928.jpg

Wow :-D

This entire project is fascinating to watch. I admire your fabrication and drive to have something different and one of a kind. It looks like it will be rather cool looking.

Personally I will stick to the factory controls. It is just too easy to change the temperature up and down now. My wife's Infinity has full climate control and it is a fully integrated system with separate controls for the driver and passenger. I just can't imagine that type of system in my 911.

Keep on posting about this. I love the watching the engineering and fabrication of the components into a full system that you will enjoy.

Karlicious, when it comes to a/c controls innovation and development, you ------>

<iframe width="854" height="480" src="https://www.youtube.com/embed/MA-C8_zgLXo" frameborder="0" allowfullscreen></iframe>

bigtime! :D

Brother Jim, Glen, MONSTERon... TY guys! Just a loose monkey kickin banana around---appreciate your commentory ~~~ and relaxing muzac :)

This morning's bananarama...

Was going to epoxy “cubby structure” together... decided instead to nut & bolt it---for potential downstream disassembly. (Not a clue why that would be needed.) 3 mm machine screws are used except for into-resin screws where 4-40 size exists. (Did not have metric drill & tap and wanted to get on with it.)

http://forums.pelicanparts.com/uploa...1477763549.jpg


Drilled = #43. Tap = 4-40NC.

http://forums.pelicanparts.com/uploa...1477763577.jpg

http://forums.pelicanparts.com/uploa...1477763618.jpg


Using sheet metal on hand… 0.032” thick. Is too thin to stand alone and so the ½” “L” addition.

http://forums.pelicanparts.com/uploa...1477763724.jpg


Am over fumbling with micro-nuts...

http://forums.pelicanparts.com/uploa...1477763786.jpg


http://forums.pelicanparts.com/uploa...1477763827.jpg


Wood... in Porsche? Sure. ¼ round mold epoxied to top rear of display panel. Idea is to screw down into this from above. (Porsche used wood for squab’s top decking and foot rest plates.)

http://forums.pelicanparts.com/uploa...1477763945.jpg


1/4 round and Arduino mount will have interference. Will grind wood away later as needed.

http://forums.pelicanparts.com/uploa...1477764065.jpg

Control shaft holes are now filled with epoxy. Will drill them later… after decision is made whether to include switches between control knobs or not. (Knob positioning depends on whether switches are in or out. Knobs will be closer to each other if switches are out. Will position farther apart if switches are in.) Center area only needs to be filled if switches are in.

http://forums.pelicanparts.com/uploa...1477765792.jpg


Will use top grain leather to cover panel’s face. Left (below) is thickness for panel, 0.048”. On right is 0.059” leather… for seat covering. Am liking thinner leather on premise that it should contour with more detail and wrap edges with a tighter radius.

http://forums.pelicanparts.com/uploa...1477765868.jpg


Goal for new AC control unit is for it to slide in and out of console. (Not sure if there'll ever be a need to go back into this thing after installing it but might as well set up for easy return.) Am testing fit here with leather included.

http://forums.pelicanparts.com/uploa...1477765959.jpg

http://forums.pelicanparts.com/uploa...1477765987.jpg


Fit is too tight to start with. Material is removed from top and sides. Final, nice-fitting panel dimensions (allowing for leather wrapping 4 sides) = 4 3/32” x 6 3/8”.

http://forums.pelicanparts.com/uploa...1477766057.jpg


John's nearing completion as I gather it. Textcom between us last night informed me of some issues he found and resolved between temp sensors and screen contrast adjustment. Way to bugkill John! You posting pics or what?! No pressure---only if you're inclined. Would be interesting to see what sort of spider's wireweb you have going.

Next on my agenda... leather covering.

Leather & Adhesive Thoughts / Notes

Epoxy gel was on menu to connect leather to panel’s face. I’ve used this adhesive to recover dash boards (with leather and vinyl---vinyl being easier to work with due to its manufactured back-side woven fabric. Leather’s uneven backing makes it more challenging to achieve a smooth topside finish when using gel.) This leather being thinner (than what I’ve used on a dash recover) will be more prone to show unwanted backside imperfections. Pre back-side inspection can be done but miss one blip… bad news. I’ve tested removing material from a dashboard when having applied epoxy gel. Leather or vinyl can be pulled off a dashboard’s surface after gel has cured and all the epoxy comes off with the material. Does require some effort (and care---or dash can snap.) Material after being pulled off is ruined---dash surface is fine.

After thinking it through, it’s evident this small panel part cannot be treated like a dashboard recover. Were this a flat piece, would be interesting to see if a vacuum bag with gel would work---believe it would. With a clear bag, the surface could be seen. Minor adjustments could be made if necessary. Given the shape of this part, there’s no bagging it.

Solution here seems to be contact cement. Am thinking Loctite. This adhesive is both very strong and heat resistant. Thanks to Mark (in seat thread) for recommending this stuff. Rather than slip sheet, I believe pretensioning the leather slightly (like a drum skin)… coating it and panel surface with adhesive, then laying the “drum skin” onto panel’s face… then progressively pressing leather down into recessed area… this seems a good path. Comments / alternative ideas are invited.

Critical here is the appearance of the leather’s surface once mounted---should be very smooth. Calls for a test of adhesive to make sure top-side finish is not dimpling.

Thanks for compliment Glen---much appreciated! In regard to maintaining factory/stock parts, it's a fine discipline to do so IMHO. There's something to be said for respecting what the designers originally conceived and what the factory boys assembled. My '79 930s were/is treated in this way. My '80 Targa is seen from a different perspective---it's an experimental canvas where deviant creative is given some extent of freedom. This project is case in point. What's being attempted here is a contemporary mod with the imposition of maintaining a Porsche look that could be said to fit an '80's interior---you can judge how this target was hit in the end.

Agreed... there's no "need" for a digital control in an '80 911... or split cabin temp control as contempo cars have. John and I are on the same page with this endeavor---we're doing it for the gratification of learning new stuff from the process and arriving at an end result that speaks of some measure of hand/mind-made quality. That is the value in the creative process as I see it. (Professionally I used to create for clients. Now I have the pleasure of creating for myself---no money, but much more satisfaction. Only thing I miss is the pressure of tight deadlines. There's something about pressure that's invigorating!...personally speaking of course.)

Why thin leather is difficult to achieve a smooth top-surface finish with:

http://forums.pelicanparts.com/uploa...1477847739.jpg


Skiving by hand makes rough... rougher. (Am not experienced with this so perhaps my technique is wrong.)

http://forums.pelicanparts.com/uploa...1477847779.jpg


Testing adhesive. Am going for worst case scenario. Is Loctite. (Perhaps different spray adhesive would not clump like this does.)

http://forums.pelicanparts.com/uploa...1477847929.jpg

http://forums.pelicanparts.com/uploa...1477847997.jpg

http://forums.pelicanparts.com/uploa...1477848060.jpg


^^^ That's not happening. Instead of researching different sprays, am back to gel epoxy. Trick with gel is sorting out beginning connection area… then what sequential stages follow. Goal = avoid putting self in corner---not simple escape after epoxy process begins. (Lessons learned from dashboard recovering apply here.)

http://forums.pelicanparts.com/uploa...1477848130.jpg


Inside curves have attachment priority. Leather’s tension while working---even this small part---is also important. Some clamps are removed to ease tension. Rubber mold might form leather into depression area. Nice idea but problem is it blocks view of leather’s surface while it’s being positioned into curves---lack of visibility = bad idea. Will think approach over and get on with it tomorrow. First area to attach is a given (below)... the inside curves.

http://forums.pelicanparts.com/uploa...1477848362.jpg

Uncle Karl,

Its always fun to watch your various projects here on PP, including the 200 page novels.

Gluing down any thin material (leather, fabric etc) is always a challenge because of the
variations in thickness. The solution is to have a consistent layer of glue on the back side. Because of the surface irregularities in the 'leather' sometimes you can try first: rolling out the surface, the back side of the leather, on a flat table with heavy roller, such as marble rolling pin or maybe a good wine bottle (northern Oregon or WA pinot, something with low Tannin). You can also try steaming the fiber before rolling. This will provide a flatter surface so you can have a consistent layer of glue. Glue wise, the 3M product group offers the widest selection and best tech support. If you are wrapping the leather around a surface you don't need much adhesive; thin layer and just the right amount of pre-cure time before you mate the two surfaces.

I was not clear on how you intend to keep the display bezel in place; your SC does not have a lot of torque off the line. Are you intending to hold it intact into the factory console's storage space by using a spring clip on the back side?

Glenn has a point with respect to easily making the common adjustments to the AC climate system; thermostat and fan speed. Many of us prefer to keep our eyes on the road and simply reach down to touch just 2 knobs. Well, most of us keep our eyes on the road, Ronnie is constantly looking at the soccer moms. I known when I was playing with various add on displays for engine management, such as a wide band display, and not wanting to give up the classic analog clock space, I was pondering putting those displays in the center console however that takes your eye off the road.

Below is a quicky adaption of the Kuehl Center Vent we did for a client's turbo that had a full height center console. Just a simple piece of black hair cell ABS with a cut out for the vent; ABS was heated and molded on the bottom to wrap around into the factory console. Just food for thought.

Keep up the great effort, I enjoyed reading about the various things you can with an Arduino thanks to your project here.

http://forums.pelicanparts.com/uploa...1477850671.jpg

Mmmmmmm, soccer moms!

http://www.merciatouristboard.org.uk...rls%20Team.jpg

"Consistent layer" note spawns the idea of spackling gel on the leather's back and allowing it to fully cure. This would level & seal the back side. Is worth a test. The Pinot idea... thought you'd use gin roller.

You're spoiled with your zupercharger CG... so SC "off the line" comment is understood... and true by comparison to ZC. Bezel came attached to display via doubled sided 3m tape. May do same. If by "bezel" you mean entire boxed unit, plan is to add 1 more set of speed nuts below existing/stock set.

Fully agree on eyes focused on what's coming next as opposed to interior distractions. For that reason, touch screen use for this screen was abandoned. My vote goes to setting temp and checking screen-info when stopped. (Local note: women---not to generalize---put makeup on here in Miami while looking in rear view... while driving 70 mph on interstate 95! Perhaps texting at speed beats that by a hair.)

Full height console is not my cup of tea. (Would like to remove what console I have! Tim offered link to bracket that mounts off clock bezel... on which display can be mounted. Plan is to get to that downstream.)

Yeah... incredible the dimensions Arduino can be taken to.

Your perverted temps are showing Rono. Regardless, you do have fine taste Bro!

Arduino Programming
 

A few weeks ago Karl issued an invitation, for anyone who could program the Arduino, to go on this fantastic voyage to design an AC control . Since I really like the Arduino and was local to him, I raised my hand to work with him in this project. In most of my projects I end up doing everything so I quite enjoyed only concentrating on the programming, while Karl did everything else (and doing an awesome job documenting it here!) After going over the different components and their suitability, Karl placed the order and we met last Monday where he gave me the box of goodies.

When using the Arduino, the sensors I typically use have voltage signals which can be read through the internal A/D converters. Here we had two potentiometers, one for setting the desired cabin temp and another for dimming the screen.

For this project we also had the one-wire interface for the evaporator, and the interface of the two DHT 21 temp/humidity sensors. These would be read by the Arduino Uno and due to my experience with the Nextion screen, we would use the serial interface for output.

While waiting for the parts I asked for a picture to model the screen output. I also read up on how to hook up the different sensors and found the proper libraries to download.

Here are the pics of the concept as done by Karl and the design in the Nextion editor (as done by me). I downloaded the appropriate font and got it as close as possible.

http://forums.pelicanparts.com/uploa...1477861711.jpg

http://forums.pelicanparts.com/uploa...1477861728.jpg

Next step was to test the individual libraries and sensors to make sure they were working right. Finally came the integration.

First I started with my Arduino mega because the UNO has only one serial port. The Nextion uses this port, but the Arduino is programmed through the same port. This means that I would have to disconnect the screen every time I programmed the system. More on the fix for this later...

This is how I proceeded:
1) Wired and programmed the Set temp. This worked fine with the Porsche knob on the potentiometer.
2) Wired and programmed ambient and cabin temps and humidity. This also operated fine when tested (DHT21)
3) Nextion screen programmed-operates fine

Items 1-3 all working together nicely.

Next day:

1) one-wire connected for Evap temp and interfaced to screen. Works really well.

2) added the contrast pot and software to dim screen. This caused problems later as I will explain...,

3) tested control routine for turning relay on off by changing the temps on the sensors. Works ok

4) on startup the Porsche logo comes on until there is at least a valid Evap and ambient reading then switches over.

5) added digital filtering to all inputs and outputs but needed to tweak input parameters

Now to the problems and solutions:

In order to port to the Arduino Uno, I used the software serial library to create an additional serial port in other pins. This allowed the Nextion to talk to the Arduino, leaving the hardwire serial port available for reprogramming without having to disconnect the screen, as Karl shouldn't have to disassemble the whole housing just to reprogram the arduino. This took some figuring out but ultimately worked like a charm.

The second problem only happened upon integration of all of the sensors. I found that the DHTs and the Arduino dimming interfered with each other. When the backlight went to less than 90%, the values of the temperature sensors would oscillate by random amounts- not good. I tried to test the dimming by not using the arduino software but to program the Nextion itself to dim as it is touched. This also provided interference. What to do? Hmmmm. I decided to change the color of the font and the background picture to simulate dimming. Voila! That worked and we have a screen that dims from full brightness to full darkness and three levels in between.

Pics to follow...

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