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Discussion Starter #1
Hi Guys,

I'm very bored and after much searching both the internet generally and on this forum I haven't found anything to help me as yet.

What is my question you ask well it is more of a possible idea.

I have a conventional computer in my car and I'm thinking of doing some modifications to various parts of the care which brought me to thinking, the HVAC controls could be relocated and that space used for something else. Then I though why relocate them to somewhere else on the dash and have them taking space when the computer could do its job for it.

So the big question is, has anyone moved/removed their HVAC unit and let a normal PC do its job for it? I have a feeling that I can't get rid of it entirely which is fine I can hide it in the dash.

What I want to do is basically copy the buttons on the HVAC unit as well as the display and have them displayed on a computer instead.

At present I'm thinking that the best thing would be to map the buttons onto a computer controlled relay card and to reposition the display by extending it. I would prefer not to do this and to just have the buttons mapped to the computer and the display on the computer as well, it would be a lot cleaner install this way.

I hope the above makes sense!

All thoughts and tips welcome. Obviously if this is done then a full write up will be given.
 

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Oscar,
Sent you the fascia monday.

I thought about moving the HEVAC control too, with a soldering iron i believe you can trash it anywhere in the car.
My idea was too trash it either in the glove box or in the cubby box.
I don't change temp often except during extreme temps.
First idea was to mold a Tablet PC vertically in the fascia. 10,4 screen would be good but lot of work. One day maybe.

About controlling it through a computer... i don't know
 

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Discussion Starter #3
Hi Flo,

Thank you for that I'll let you know when it arrives.

I'm thinking of placing the HVAC controls up inside the dash somewhere and want to work out a way to use a computer to control it in parallel instead as then I have more space for other ideas on the dash. For example I can put back my vents and move the touchscreen down to where the HVAC controls are at the moment, behind that I can put the computer and therefore free up the glove box and use it as it was intended (I have the mac-mini in there at the moment).

I don't suppose anyone has a wiring diagram for the internals of the HVAC unit? I've had a look in rave and that gives some information but very little.

Cheers
 

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good idea, keep us posted.

I've been toying with the idea of a full computer in the back to run in-flight movies for the kids, GPS for driver, satelite internet for passenger etc etc.... but then the reality of time hits me.

Adding HVAC controlls and super-wham-i-dine trip computer wouldn't be too hard ( I assume).

You could replace the HVAC head unit all together, make a new board to interface with the computer & drive everything from the PC. you could even set up a timer to lower the windows a touch, and turn on the fans 10 min before you leave work on hot days, so you're not getting into an oven.
 

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You could replace the HVAC head unit all together, make a new board to interface with the computer & drive everything from the PC. you could even set up a timer to lower the windows a touch, and turn on the fans 10 min before you leave work on hot days, so you're not getting into an oven.
That is an interesting idea. I work for a flight simulation development firm, and interface custom hardware with the simulator computers all the time. Wiring the controls to a controller board won't be hard, its writing the software thats a pain in the arse :( .
 

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Discussion Starter #6
I have a USB experiment board that will do the trick and it allows for writing ones own software. The hard part is going to be getting the information from the display into the computer to then have the computer display the information on its screen rather than/as well as on the original screen. Writing the interface to control the buttons won't be too hard and with a bit of photoshop one can make it either look the same or give it a face lift.

The are a couple of problems with having the fans turn on before you get into the car is that a, the computer takes quite a bit of power and would probably leave you with a dead batter within an hour or so of the engine not running, b, at present the computer turns off when the engine is turned off c, even if the computer was on and did replace the HVAC unit there wouldn't be any power to the fans whilst the ignition is off.

I'm not planning on replacing the HVAC completely just creating a system to allow me to control it remotely.

Scott, I don't suppose you have any ideas on how one might go about taking the input to the current screen (thinking of intercepting it just before the screen) and inputting it into a computer? I'm thinking that a VDU controller that normally outputs could be used to receive instead and then as one makes changes on the HVAC unit one informs the computer what the signal being received represents, and then what it should do, in this case show the equivalent image. There are only so many things that can be displayed on the HVAC display and some of the images are pre-stamped as it were and therefore can't be changed.

On a side note and I have been wanting a proper (well modern) trip computer as well as I would really like to see the current fuel consumption rather than the average, only problem here is working out how the heck to get the information needed. If anyone has done this as well then please let me know could be an interesting add on.

Cheers
 

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mariner82 said:
On a side note and I have been wanting a proper (well modern) trip computer as well as I would really like to see the current fuel consumption rather than the average, only problem here is working out how the heck to get the information needed. If anyone has done this as well then please let me know could be an interesting add on.

Cheers
A ELM327 with proper software could show current fuel consumption, at least an ScanGauge II can do it.
 

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Well making the hard code won't be difficult, its going to be tough making a nice graphical interface for it. Thats when C+ or visual basic comes in :oops: .
 

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The HEVAC control 'Head Unit' is the actual 'ECU' reading the inputs from the various sources and applying the required outputs accordingly. Hope this helps in some way as logically it would only need an input interface to the pc then an output interface, software controlled, between the pc and the various heating/cooling components.
cheers John
 

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Discussion Starter #10
Hi John,

Thank you for the info, I had my suspicions that this might be the case which is why I'm not planning on replacing it just remote controlling it in effect.

Cheers,
 

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Interesting... I've kicked around the idea of replacing it as part of an onboard computer. But the "remote control" takes out the risk of missing some important function that the control might have.

I agree the inputs ( buttons, sensors ) are trivial. Reading the output {LCD} won't be too difficult. It either has a parallel bus or, more likely, it's got a line for each of the 'segments'. Wish I had a spare to play with.
 

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Discussion Starter #12
I'm planning on getting a spare to play with when I find one at a descent price, my plan is to keep the original so that I can put it back to normal at any time. I had also though about replacing the HVAC unit with a computer but not knowing how it makes its decisions and how it reads the various sensors makes it a rather difficult proposition and as such I have dismissed that idea. Also I fear that the BECM might throw up some interesting errors if you decided to remove the HVAC unit which is my biggest concern. If I get this working I will of couse post details for everyone. Just have to make sure that this idea doesn't fall buy the way side like so many others.

As I'm planing on going this route of remote controlling the HVAC I thought that I might get rid of some of the other buttons as well (with the exception of the emergency indicators switch, don't think the MOT chaps will like that being removed) as that would give even more space to play with. A larger screen perhaps. Can't quite decide if I should be removing the hight selection or not, need to work out if that is integral to the EAS system of electronics or not. If it is then it will also have to be remote controlled. Safest option might be to remote control all those switches. Some are more difficult than others, lights for example (my BECM is set to always turn on the head lights as this is the law in Sweden). The latching switches shouldn't be too difficult as this will be a programming setting as to whether or not the switch is kept closed or not.

The next issue once the remote controlling has been worked out is getting a copy of windows (XP perhaps) to load within a couple of seconds. This shouldn't be too difficult as it requires the removal of several services the problem will be to keep only the services that will be of any use directly. Time to play with the automated installation tool.

If anyone wants to help in any of this then please feel free, the biggest issue that faces me is the remote viewing of the screen on the HVAC unit as I have no experience with display output. I already have a friend helping me with the programming of the switches and I can do the photo shop of the buttons without a problem.

The up side to all of this other than the amount of space that will be left is that you can change the appearance of the switches at the press of a button (no pun intended). You can create your own layout and colour scheme and just upload it into the computer.
 

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Discussion Starter #13
It has just occurred to me that reading the display isn't even necessary as all the display does is affirm the selections made. What will need to be done though is to set the controls to a default such as auto at 18 degrees C. That way the display that is created for the program can be set as default (initial start up what ever you want to call it) to this and as long as the line up the first time everything is connected the job is done. After that it is a case of making the program that is remote controlling the HVAC unit remember the previously used settings and you are away. This makes life so much easier!

As I don't have my rangie with me, could someone please confirm what information is displayed on the HVAC screen? From memory the following is displayed:

Left temp setting
Right temp setting
AUTO
PROG
Fan speed if not in auto
Exterior temp (this won't be included if the display is not read however I don't think that mine is accurate any how so I don't miss it one can always be installed and connected to the computer.)

I don't think that I have missed anything as if memory serves (never used these buttons) the directional buttons have lights to show if they have been selected as does the A/C off, interior circulation, and seat heating buttons.
 

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You forgot the big one - the "book" ;)

The ECU remembers the L/R temp setting from one run to the next. I think you need to have it tell you those somehow. I've got to replace bulbs, I'll have a look at the LCD interface soon.

External temp is important for me, but you could tap the sensor directly. In fact, I'd like to add at least a couple more temp sensors (int & ext).


Joel.
 

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Discussion Starter #15
Ahh the book! Yes that would be a big one! Luckily I've never had the book show up. If the display does work on the bases that there is a line per item of information on the screen then it should be possible to link the line for the book up to say an LED or an input into the computer and then just use the rest as you make changes on the computer. I don't know how accurate your external sensor is however mine can read plus degrees for some time when I know very well that it is several minus degrees outside. Last time this happened to me it was -10 out but the HVAC ext. temp read +20 or so it did go down after about 20 mins driving but it was still far from the truth, which is why I'm not bothered about loosing it. I can just as easily add in one that I know will work properly, it wouldn't be hard to make it show a picture of a snow flake if the temp went below +3 centigrade as it does currently. Whilst I'm adding in a new sensor I could also include one for the left and the right so that a comparison can be made between the temperature set and the temperature achieved.
 

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I'm not sure why you need to move the HVAC. Seems alot to do to retain a clock and a sunglass holder.

This is a much better idea IMO (depending on screen glare)


I know there are quite a few people on mp3car who have cracked the BMW codes and can do all sorts of things with their carputer (windows, sunroof, climate etc). Would pay to have a hunt round over there and see if anyone's tried what you're looking at.
 

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Discussion Starter #17
Hi Rogan,

I wasn't planning on keeping the clock or the cubby space really. I might even go to the extent of removing all the buttons with the exception of the emergency indicators (I don't think the MOT people will like not having that all the time).

Thank you for the tip of looking on mp3car, I have looked there and I couldn't find anything relating to our cars and the HVAC system. I did find that as you say several people have managed to remote control the HVAC unit for their various cars though.

The idea of having such a large screen is an interesting one however I would prefer to have a touch screen, at least that way I wouldn't have to mould in a mouse and hide a keyboard (I think that chap put it in the sun visor). I have quite a nice 10" touch screen sitting around which would do the job nicely which I'm planning on using. I can't remember how big the one that this guys put in was, I think it was a 12" or a 15" one.

At the moment I'm thinking of putting the window switches onto the computer as well, just can't decide what to put in their place. Perhaps a proper cup holder, one that doesn't allow cans of the slimmer variety to go flying around. Perhaps a holder for stuff, I have a rather large bunch of keys which always seem to get in the way as soon as I get in the car and I need them for the start and the end of my journeys (can't get away from or back to home without them).
 
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