I have a LCD display, that is designed to display water temp, oil temp / pressure etc. The unit which takes input from a sensor and display the output on the LCD screen is missing. Can anyone give me a clue on what would be required to create a unit to do this and how easy / difficult it would be.
What skills do you have? Can you solder? Name 3 of the 555s pins from memory. Design a 2 transistor properly biased amplifier? Design a suitable driver chip using only magic marker?
Is the LCD just a bare LCD, or does it include some driver electronics.
Yes it's a Stack, it's quite an old one and they don't stock the unit to drive the display anymore. Come to think of it, I guess there will be electronics to drive the lcd screen in the dash it's self, but I would have to open it up and take a look.
My skills are zero in terms of electrical engineering, although im pretty sure I could use a soldering iron.
Hard to say what it needs, then - the current models seem to vary between some with the car-specific electronics in the display and some with a dumb display that would need a complete set of measurement electronics. Since you think it had a separate driver box, I'd guess at the latter : the display is probably just a generic LCD (probably with RS232 inputs - there is a current model like that) and you may as well start from scratch. You'd have to open it up and describe the components in some detail to get any further.
Or keep an eye on ebay - there are a couple of Stack bits there at the moment.
Ok. Best case - all the driving electronics is in the dash unit, and you just have to supply it with the right 0-5V (or whatever) voltages. If you cannot find manuals, it's probably going to take at least weeks to learn (several hours a day) how to make an interface unit that will take the voltages/currents/resistances/... from your cars sensors, and convert them to the form the unit expects.
If it's either digital, as it may well be, or wants the LCDs driven at a more basic level, then probably months of work.
I (if I had it, and wanted to do it) as a reasonably skilled person that's designed a couple of small microcontroller units, temperature controllers and stuff, would expect to have an idea of what it needed after an hour of opening it. I would be very, very surprised if it took me less than a couple of days to get anything working, and a week to get it fully up and running, and installed. (couple of hours a day) I would not be surprised if it took a month, though would possibly have given up by then.
Lack of documentation is a truly horrible thing - you may be faced with essentially wires going into blobs of unmarked silicon, that you can get no documentation on. If you start with a working system, then it's possible to reverse engineer fairly easily. Otherwise, it just gets horribly complex, and as a novice (or even for someone experienced) not having documentation can lead to irreversable mistakes. Such as making an educated guess about something being a power line, when in fact it's a critical data line that will blow if you try to feed power in to it.
Without seeing the device, I won't say that it's impossible that you could do it, but at best, you're likely to need to learn a hell of a lot more than you do about electronics before attempting it.
Firstly, try to find documentation, if possible. User groups for cars with it, ...
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