3 knob HVAC control upgrade
#196
Rennlist Member
Family first Al! We can wait a little longer! $$ sounds fair and I think you will have good demand as I know I am anxiously awaiting its arrival! If you do go the automated route and there are any setup costs let the community know, I would be willing to throw in $$.
#198
Thread Starter
Could be an option. I would need to generate a complete set of instructions for DIY, including the tuning steps. Might free up hours for me, or might turn into a giant problem too.... Have to think about that....
#200
Thread Starter
Yep, still here, still working at it slowly. Got the 3rd unit assembled (left in picture), and it tests fine with my function check program. This will be for my car, so need to do some jumper wire work to make it plug-and-play into the stock harness. I will also make wire connections to the fan amp I installed, so I can test both stock resistor pack and the variable fan speed with just a couple changes. The middle unit is the first field test assembly, and it has pigtails setup per request for a custom application. The housing is a combination of 3D SLS printed parts and 21ga steel - a much cheaper option than 3D printed housing for the entire shell. This unit is holding here while I still try to figure out the more advanced programming on the control. My concrete wall is still having the buttons override the Mode **** functionality - it's been a battle! The right one in the pic is my programming/test unit where I'll experiment with programming in the future, and be able to recreate problems for diagnosis if required. I have 1 more circuit board set here, and all the parts to complete that, including the 3D SLS parts and steel housings - that will be the other field test unit when it is ready.
Last is Frances, the weinerdog! She has been great therapy for us while Carolyn is going through this cancer process - she deserves recognition for patience and compassion!! Thanks to all interested in this, sorry it is not completed and out there already.....
Last is Frances, the weinerdog! She has been great therapy for us while Carolyn is going through this cancer process - she deserves recognition for patience and compassion!! Thanks to all interested in this, sorry it is not completed and out there already.....
#201
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Join Date: Jul 2008
Location: The Republic of Texas
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Hey Al,
Great work, very impressive...I literally cannot fathom what it would take to do the same...
FWIW, I prefer the ***** on the far right unit...because they do not have the silver accent rings like the others...
I feel the solid black ***** are a better match for the rest in the 928 interior...
My two cents, and thanks,
Rich
Great work, very impressive...I literally cannot fathom what it would take to do the same...
FWIW, I prefer the ***** on the far right unit...because they do not have the silver accent rings like the others...
I feel the solid black ***** are a better match for the rest in the 928 interior...
My two cents, and thanks,
Rich
Last edited by V33; 02-07-2017 at 10:24 PM. Reason: spelling
#203
Thread Starter
I agree the non-chrome trim ***** match the original style better than the other 2. Plus, they fit in the stock space available! The 2010+ ***** with the chrome trim will work for my car with the round louvers (chrome trim rings) and the dash gauge trim rings I made, but a non-stock fascia space.
#208
Thread Starter
No recent progress on this - been focused on personal life and some on my 928 since last fall. But, expecting that when I'm back into my interior - next month I hope, that I'll get my test unit installed and running in my car. If that proves survivable, then field test units will be sent out.
#209
Thread Starter
Well, life is getting back on track here. Getting some good progress on the code for this control in the last couple weeks! Last night I got the AUTO temp control working with the on-board sensor, so the stock sensor string is ignored. And also solved the logic problem for the MODE ****, the AC and Recirc now behave as expected when the MODE demands them. The fan control now has ramping (when using a fan amplifier), and this can be controlled in the AUTO mode.
Still need to get the background lighting circuit tested with the stock reostat - that is some breadboard work before I solder the parts onto the circuit boards. The lighting works now as stand-alone, and is designed to work with a PWM LED controller like Ed's, but still to be tested.
Hopefully get my test unit final wired so it can be tried in my car in the next 2 weeks! There is a new board design on-going to commonize some parts and replace some obsolete items, but pretty minor changes really. The code is working, but I need to go through it with an eye for reliability and fail-safe.
Still need to get the background lighting circuit tested with the stock reostat - that is some breadboard work before I solder the parts onto the circuit boards. The lighting works now as stand-alone, and is designed to work with a PWM LED controller like Ed's, but still to be tested.
Hopefully get my test unit final wired so it can be tried in my car in the next 2 weeks! There is a new board design on-going to commonize some parts and replace some obsolete items, but pretty minor changes really. The code is working, but I need to go through it with an eye for reliability and fail-safe.