hans14914

I will try and come up with something quick for the "demanding" rear AC crowd. Remember, that the two systems are not integrated at all in the factory setup. I am out of pins on the less expensive microcontroller, which is contributing to the issue. To easily add the support for the rear AC, I need to delete other more important features, or move up to both a more expensive and larger micro-controller. If you guys didnt insist on the LCD we would have the spare pins.

I do not view it as taking away features, they were not there to begin with, and I am not forcing anyone to remove their factory rear AC from the stock location. It can stay in that general area, or be moved to a more inconspicuous location. I will look into slaving another smaller micro for a dedicated rear control module. I think the core unit is ready to move into the public beta stage though, so leaning towards getting it out as-is.

Regarding using an iPad - I can easily make all the bracketry and framework for this with infrastructure I have already developed. However, i do not have the ability to write the software, nor do I have the finances to hire that job out. If someone wants to take on that project, I would gladly offer to sell them an iPad console insert and the climate hardware.

Thanks
Hans

Rod Underwood

I'll just take what you have right now. ;-)

Rod
Keep banging away. ;-)

blown 87

Damn brother, I never meant to be demanding.

PS, I did not insist on the LCD, and I am not insisting on the rear AC controls being intergrated either.
Bottom line is you are going to sell them in either configuration, so you do what you think is best.

If it were up to me I would say go bigger on the controller, so you will have spare pins for future improvements down the line while these units are out in the field, but it is not up to me.

hans14914

Greg,

I am looking into it for you buddy. You know how it is, cant make everyone 100% happy 100% of the time. Worse case scenario, I release the V1.0 as it is, and make you something special as I have time. Technically, I can create a voltage divider mode by using two of the discrete digital rheostats. but that would add a ton of extra components onto the build, but I could do it for you.

I guess a good question for you Greg is how many steps of adjustment in the rear AC temperature would make you satisfied. If its a small enough number, I may be able to come up with something before closing this design.

Thanks
Hans

blown 87

Just fan speed would be enough, and again, you do what you need to do.

For the time being I could live with relocation to the extra slots in the handbrake cover, but I do plan on doing a euro style electronic adjuster for the lights as soon as we can gather the parts,. but that may be a year or more down the road.

So if this is just for me, lets just relocate them for now.
Not trying to be hard to deal with here.

blown 87

Glenn M

Hans,
Great job with this project, I appreciate all the time you have put into this.

For the rear AC I would think max cool - off with three speeds would be fine. Most of us use it to help cool the car down.

Thanks!

hans14914

I talked to "Naysayer" Greg over the weekend.... turns out it was just a bit of a misunderstanding. Looks like 99.9% of people are onboard for setting the AC to full cold, and then just modulating the fanspeed.

I locked down the schematics, and have the rear AC board all laid out. Only three more boards to go.

The rear AC board has a trimpot to adjust the default temperature. I will set these to full cold before shipping them, but a user can adjust this to a different default temp if they would like. It is user adjustable, but it will get buried in the console, so not easily adjustable after installation. The board supports the stock three fan-speeds using the original resistor pack. There is also a jumper which will pass a PWM signal through the max fan-speed terminal. This is for future expansion or user experimentation. I personally dont think its worth the expense to add a FET module for infinite variability of the rear fan, but its fully supported now for those tweakers.

The primary input/outputs are on 0.25" male quick-connect terminals which will allow for any number of easily modifiable/custom harnesses using common parts and tools - very similar to the current version of the 79-89 window control module.

Interface to the board is done via an IDC16 ribbon cable. Again, IDC ribbons can be easily made/modified using common tools and parts. This will allow users to extend or shorten the harness as necessary. Another interesting function is that IDC ribbons can be "terminated" in the middle of a ribbon. For those with any basic computer hardware experience, the IDE40 and floppy drive ribbons are a good example. They have a connector on the end, and also one in the middle. I bring this up as the rear climate board is designed to be an intermediary device.

The main controller has up to 16 user addressable spare outputs. They are via a Darlington array (ULN2803) which will sink a fair amount of current - they can drive a relay coil or LED directly. The output connection from the main controller is an IDC16 socket. *IF* the user has rear AC, then the first 4 pins are used for the rear AC control. The remaining 12 outputs are available. *IF* the user has no rear AC, All 16 outputs are available. The ribbon connection allows the same IDC16 cable to control both the rear AC board and a breakout board. When the rear AC board is connected, the first four outputs on the breakout board can not be used (technically they will function in tandem with the rear AC elements... but it will be recommend to disregard those outputs, and not used them).

This should allow for the ultimate level of modularity. A customer will have the option of running any combination (or none) of the auxiliary output boards.

The primary output board is connected to the controller via an IDC40 connector. I am using an IDC40 again, for the ease of modification, and it allows me to double the number of wires used for each function. Each wire in an IDC40-26g will cary approximately 1.6a with a nominal temp rise on the copper. While this technically is enough for any of the vacuum solenoids or relays, I have doubled those to reduce the temp rise on the wire. The power and ground connections use 6 pins each... and there are other functions which use a different number based on their power requirement.

The connection board itself has the factory card-edge connector, the IDC40 socket, and then 0.25" male quick-connects for input of constant +12v for the microcontroller as well as input and output for the blower. There are also ATC/ATO fuse holders for protecting the switched +12v bus, the constant +12v bus, and the AC compressor control bus. There is also a jumper on the board for selecting what function the defrost relay has. In one position, the factory defrost relay is used, in the second position, it routs the signal to an on-board relay for both future expansion and the possibility to eliminate the factory defrost relay for troubleshooting (I recently ran into a bad defrost relay causing some "Magic Blower Syndrome" like symptoms, and would like to provide a set of tools to isolate the relay for troubleshooting).

That about sums it up. I anticipate having enough time to finish the board layout for the primary connection board tonight.... and then it will probably take a couple days to tweak the control board layout to my liking. There are a couple of elements on the board with thermal consideration... and its going to take some extra copper pours and thermal vias, which are a bit of a pain when working with a small outline.

I will post pictures of the output boards latter, but they are not very impressive looking.

Thanks
Hans

Tom in Austin

Can't wait to see and experience this in person!

blown 87

I really am starting to think that we may actually have a working Carputer soon.
Not that I have time to put mine in when I get it or anything.

Maybe we can all chip in and spring for a nice dinner or something for you and Katie when this is done, or maybe just for Katie...................

blown 87

You have not seen the demos he has put on?

FLYVMO

Hans,

Will the board support PWM of the ventilation fan, when it is delivered? I see it is a "future expansion thing" at the moment. I would definitely pay extra for a PWM module to control the "main" ventilation fan and not have to use the resistor pack.

Looks like you have made great progress and you have my deepest thanks and admiration for getting this project so far. I am definitely buying a setup when it is ready!

Cheers!
Carl
1990GT shell

hans14914

Sorry guys, been busy laying out board

Carl- the primary blower absolutely has infinite modulation via a PWM/FET module. The rear fan is the one which is supported but not included. This may change, but I already have that board done. There is a jumper on the rear-AC board, and also on the control-board. In one position, it passes control down for the "third speed" of the factory system, in the other position, it passes a PWM signal to the same output so a stand-alone FET output module can be used in the future. I am working with someone regarding some advanced FET modules, and if we can come to a deal, I may be able to justify this for the rear.

I am going to switch over to my layout PC... got 30% of the control board done yesterday... going to try and get the rest of it done today.

Thanks,
Hans

Speedtoys

Nope.

Someone should create a video capturing device, and write a WWW site to upload it to.

blown 87

When they get shipped I am sure you will have more vids and pictures than you will want to look at.

As I have said before, I am really excited about this project, just from a data collection standpoint, not to mention being able to get the GPS and sat radio off of my windshield.