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Build your own HUD for the Fiero, HELP

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Capt Fiero View Drop Down
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    Posted: 29 November 2009 at 10:41pm

Ok this is what I want to build for the V8 as the stock Speedo that only goes to 180kph is just not going to cut it.  Heck its almost useless in the 88GT.  I am reading over this and frankly it is so far above my normal projects I am at a loss.  Can anyone offer any info that a beginner might want to start this.  That sparkfun place has that "free day"  Yes free stuff and I want to take advantage of it to get most of my parts, however can't even tell if they have what I will need.  The link to the spark fun special is here.  

http://www.sparkfun.com/commerce/news.php?id=305 

If anyone can offer assistance I would be greatly appreciated.

Heads-Up Display Speedometer

    The idea for this circuit originated on the Fiero mailing list. One listmember saw a HUD-Speedo on another car and asked me if it was possible to have something like this on the Fiero. Sure, it's possible.

    Good news: the HUD is now available commercially! Please contact Bob Williams for details!

    I came up with this little circuit that fits on a circuit board less than 2.5" x 2.5" and fits in a small box. I used Conrad Electronics P/N #522848 and it fits great. But any other box should do as well.

    The circuit consists of a small microcontroller and three 7-segment LEDs. The controller is responsible for measuring the speed and driving the LEDs. The reading on the display is mirrored, and the unit should be placed on the dash facing up. That way the reflection of the bright LEDs can be read on the windshield. A good place to mount the HUD is on top of the extra gauge cluster (at least on V6's). That way the reflection will appear right next to the rear view mirror. The image is not too bright at night, but bright enough during the day for most driving conditions. After all, this is not a HUD for a $30 million F16, but only for a $1-10K Fiero (although it is almost as much fun to drive and gets better mileage too!).

    BTW, a jumper is provided to select either mph or km/h, so people can use it whether they are in the US, Canada or Europe.

    The voltage regulator is National Semiconductor's LM2940-5.0V, which is designed for automotive use and can withstand over- and undervoltages of +/-60V.

    If you want a programmed CPU I will provide it at cost to whoever wants one, for noncommercial purposes only!

    Schematics

    Installation is simple and only three wires need to be connected: Ground, Ignition and the Speedometer output. This is the output that feeds the ECM and Cruise Control (if equipped). Refer to the Helms manual for wiring details.

    If you want to make your own printed circuit board, you can find the layout for this and many other of my projects here

    A word on cooling: in the worst case with all segments on on two digits and two segments on on one digit the circuit draws around 100mA current. At a battery voltage of 14 Volts the regulator converts 0.9W max. into heat. To prevent the regulator from dying of overheating (actually it shuts down, but you want the HUD to work under all conditions, right?), you can either

    • Put a resistor in the power supply line. A 47 Ohm/2W resistor brings the "heater" down to 0.4W
    • Provide sufficient cooling (a little piece of metal with good thermal contact will do)
    • Use a switching regulator instead. This is the best solution, but also more expensive as it requires special parts.

    Here is the parts list:

    AT89C2051 with program "HUD"
    12 MHz crystal
    3 LED displays, SL1119 or D350PA or TLR369 or TDSR5150 or similar
    LM2940-5.0V
    3x BC808 SMD
    BC 847 SMD
    ZPD4V7 SMD
    P6KE6.8CA
    7x 150 Ohm SMD
    3x 4k7 Ohm SMD
    1x 47k Ohm SMD
    2x 33p SMD
    3x 100nF SMD
    2,2uF/16V SMD
    20 pin socket

Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.
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Dawg View Drop Down
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Post Options Post Options   Quote Dawg Quote  Post ReplyReply Direct Link To This Post Posted: 30 November 2009 at 1:15am
There's a couple things I don't like about his circuit.  One is the fact that he's using a programable chip.  This means you're totally dependant on this guy to supply you with a chip.

Two, he lists SMD components which are hard to work with.

If you gather up the parts, I can certainly help you build it.

Cheers

DG
You dream it up....I'll make it
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Capt Fiero View Drop Down
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Post Options Post Options   Quote Capt Fiero Quote  Post ReplyReply Direct Link To This Post Posted: 30 November 2009 at 3:33pm

 

 Thanks for the offer and if I get all the parts together, I'll take you up on it.  This would be a nice project for me to do come this winter when its too cold to be outside tinkering with the stuff.

Anyone else notice that next week we are suppose to be drop to sub zero temps.

Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.
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