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Old 07-15-2008, 09:53 AM
eldoradoboy eldoradoboy is offline
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im actually working on such a project or at least similar project for my monte carlo.... I am running a Nordskog digital dash currently for my main gauges and so i havent gotten so far into the actual gauge part of it yet but its very doable with some hardware.... however there some things to consider..

1] most sensors for temp / oil P / fuel are standard 0-5 volt sensors... my temp gauge is a thermistor type that provides voltages based on tempaerature.. a GM fuel gauge is a 0-90 ohm unit. so same thing send out 5 volts and see how much you get back.. oil pressure as well...

speedometer / odometer is handled by a sensor that screws into your transmission and creates electrical pulses based on speed.. im using one from nordskog that is I believe 8000 PPM (pulses per Mile) so in your software you keep a running count of every pulse.. query it say every second and there you go calculate the speed.. and also the distance driven...

these can be handled using a Basic Stamp processor with just a little bit of circuitry to monitor... the temp gauge being the toughest as most temp gauges are non-linear so you have to have a lookup table..... speed sensor pulses can easily be read with the basic stamp as well... then connect the stamp to a "carputer" that will have the processing power and VGA output to drive your screen..

now in my case im not going the gauge route just yet - although it is in the thoughts for the future... just tough to find a screen size that will even stand a chanceat fitting in my dash and looking decent... im going for the center stack thus far... so im working on HVAC control, Music, Navigation, Internet access, trackability (track my car whereabouts), and the capability that if I go TPI or fuel injection i can monitor the car's systems...

HVAC: the same basic stamp i talked of earlier.. only a second one will control my HVAC in the following manner.. the GM HVAC system consists of vacuum operated doors to change the air deflection to the vents, floor, defrost, or combo of those.. as well as vacuum to close the heater water valve and also the air-recirculation door.... since these devices are not modulated merely just "on or off" vacuum solenoids will be used for these...

the Hot / cold air mix door is cable driven... but just so happens that cadillac used a servo to drive theirs... and it mounts nicely to about any GM box... early - late 80's cadillacs are great for these... they also return a 0-5 volt signal that tells you the position of the servo... monitor it and you'll know how far open or closed the door is... nifty huh?

Fan speed control: Cadillac used a variable fan speed control in the cars mentioned above also... it took a 0-5 volt signal and boosted it to a 0-12 volt signal for variable speed on the interior blower.... basic stamp and a dallas 1 wire variable pot with a 5 volt input signal.. and you are rockin!

now the Hard part!! how to find a screen that is bright enough in daylight to be visible.. you know when the sun pops in from over your shoulder right on the dash... and also can be dimmed for night vision.. so far i havent found a screen I like yet....

but to answer your question yes this is all very possible and something im interested in enough that ive started to play with it and build some electronics for... now I havent written any of the software for it yet... although spftware does exist for carputers already including some dash stuff.. I'll probably end up writing my own in VB.NET or if the serial ports give me too much fits in .NET ill write it in VB6....
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