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Thread: A/C Control Electrical,Vacuum, and Mechanical

  1. #1
    Newbie z28control's Avatar
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    A/C Control Electrical,Vacuum, and Mechanical

    I've been working this project for a couple of months now and wanted to post some of the progress to get feedback.(Hopefully Positive)

    In order to mount the screen I used from an older laptop I needed to make room in the center dash area. I had to remove the A/C controls that were once located in the bottom 3"-4" of what is now the screen. The screen is 13.3" with an easyscreen resistive touch panel. The laptop was then cut in half at the base to fit it in the console and still allow access to the CD/DVD. I have divided my project into three phases to help explain the method in which I choose what is important at any given time.

    Phase 1 - Develop a system, gather hardware, make a plan, and prove that it can be done.

    Phase2 - Make it work reliably (Easier said than done has been my experience)

    Phase 3 - Make it pretty.

    As of right now I am in phase 1.5 on all of the systems I plan to integrate.

    The first and easiest part of the A/C system was the fan speed. Since this is all done electrically I used 30 amp relays with the coils powered from the single board computer.



    The next task was to develop a system to control the vacuum actuators. I was fortunate enough to run across some micro SOVs at a laboratory equipment sale. They are manufactured by Clippard The type I am using is the EC-3M series on a 6 hole mounting bar. The price for new 12V solenoids is $20.90 ea., the manifold for 6 is $13.00 and misc. fittings ~$10. The valves I have are 24 Volt (The EC-3M is available in 12V) so I had to use power from my laptop P/S (19V). I used a relay box to isolate the SBC from the 19 Volt power. I then hooked the engine vacuum to the manifold common and the 5 color coded hoses to each valve. To determine the correct sequence for the vents I blew air through the vacuum selector valve and determined which hoses were used in each vent configuration.


    The last control was the Hot/Cold selector. This is a large flap that swings between the A/C Condenser and the heater core. This flap was controlled by a cable driven knob. I decided to use a servo to control this function. RC servos are controlled by A PWM signal. This signal has a pulse that repeats every 20 - 50 ms. The time of the on pulse dictates the position of the servo. The two main ways I found to control the position was by using a serial port interface or a IC timer circuit. I needed to use the timer cicuit because I am using my SBC to control the position. (Analog 10Volt Out Channel) Instead of building a custom circuit I found an RC Servo tester on Ebay and jumpered my analog signal across the fixed resistor. The first pass at servo mounting hardware was horrible.(No pictures, Thankfully) It did however prove that the servo idea would work. I then had a custom mount machined from aluminum. The black assembly at the end of the cable is what actually turns the flap.



    To help speed the development stage of the control system I have been using a program from microcommander.com This package installs a stand-alone kernel on the SBC and provides a graphic interface on my Win machine. This program is very quick and easy to integrate. The down side is that it does not utilize the full capability of the Z-World BL2100 SBC. Sometime in Phase 2 I plan to use Dynamic C (embedded language included with 2100) to make a better application for pc based car control. The pictures I took are not very good. I was going to take better pics but ran into a hardware problem on my SBC. Hope to have that fixed soon! I hate to operate in manual mode.


    I will continue to make updates as significant progress occurs.[LEFT]
    ------------------------------------------------------
    Car PC - If you have to ask why, you'll never understand.
    XAA289.com

  2. #2
    FLAC mp3z24's Avatar
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    Frickin amazing!!!!!

    Good job man, you have my respect!

    ~Mike
    Single Member of the "1000 Post and No MP3 Car" Club
    PROJECT ON INDEFINATE HOLD... BOUGHT A HOUSE
    2000 Cavalier Z24 [###-------] Only 30% Done ... Still

  3. #3
    Newbie
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    I have seen his (Z28Control) AC unit in action.... It is truly amazing... Still has a way to go on the rest, but man the potential of this combination with a SBC is awsome!!

  4. #4
    Constant Bitrate mugu's Avatar
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    More texans, good to see. I was interested in doing something similiar, thanks for the inspiration :}

  5. #5
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    thanks man. I have an 86 Z28 and wanted to do the same thing but didnt know where to start. Now I do. Thanks again.

  6. #6
    FLAC guitar333's Avatar
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    wow excellent work
    92 Taurus SHO - Daily driver - Epia M10000 80GB 512mb 7" touchscreen, Opus PSU etc

    93 Black SHO - 30mpg cruiser

    90 Silver SHO - 419whp fun/project car, CarPC to come (for tuning)

  7. #7
    Newbie msumr282's Avatar
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    I have a '93 MR2. The USDM setup has a cable-controlled temperature valve. The modes are controlled by a couple of stepper motors. The fan is controlled by a series of varying resistors, each connected to its respective fan speed selection.

    Can someone help me with what I need to obtain to make this project work? I know that I will need a servo to control the cable-controlled temperature valve. Can someone give me a brief explanation on stepper motors and resistors? I am not sure what the best way to go about controling these with the carputer would be and any help would be much appreciated. I am not really looking for a fully automatic setup as my car is really only a 3 seasons car and the climate control is not in regular use like many other cars. I like to take the t-tops off I am just looking for a simple yet effective control of the pre-existing controls only through the carputer.

    Thanks Guys

    Joe

  8. #8
    Newbie msumr282's Avatar
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    Can anyone please help? I am fairly new and am still trying to fiigure things out and there isn't enough information available on the searches.

  9. #9
    Constant Bitrate
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    Hey i was wondering if there was any more progress in this?

    you have me really curious ... i'd love to do this and i have the same car as u(well close .. i have a 99z28)
    1999 Camaro z28
    -- Computer installed :) Phase 1
    -- z28 302hp dynoed :( WAHH!!!!

  10. #10
    Low Bitrate
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    Jun 2003
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    have always wanted to do that, but haven't ever started due to fear of not being able to figure everything out (esp. the vacuum tubes). im impressed, and jealous of your knowledge! where did you learn all the necessary info to do this? does your job somehow address any of these issues? Ryan

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