40x4 lcd for monitoring car sensors?


New member
Ive been thinking of connecting a 40x4 lcd to display sensor readouts like water temp, oil preasure, volt, amp. ect.
I know it would involve a processor of some sort, and a rom memory, but where could I find info on these components, and where would I get a schematic on how to build something like this, and were would I acquire the sensors to input the information to the lcd, Ive been seaching this forum and the web with out any luck.
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CF Tech

That is a big project, of which frankly, the LCD is only a small part.

I think there is a project somewhere to read the diagnostic codes out of the on board computers in ther cars.


New member
Unless you are using an aftermarket engine managment computer in your vehicle, you will run into problems interfacing your LCD display unit to the computer. In australian cars atleast, the EMS uses a custom diagnostic interface which is completely different between models of car and finding pinouts is almost impossible since the manufacturer doesnt want you pluggin anything into the system, plus the data sent over that interface is itself encrypted, and rather heavily (512bit) on current model vehicles.

About the only way to do it easily would be to build a small computer with it's own sensors connected to the car, and use the data from them


New member
Where would I find more info?

Well Im in the US so I don't think i'll run into encrypted problems, their is a ton of companies that make aftermarket anolog meters for my car (volt,temp ect.) But I would really like to have it displayed on a 40x4 lcd, please anyone with some info on how to get it done.

Thanks so much


New member
I tried doing a similar project. You can buy a digital outputting sensor rather than the analog signal. These are pretty cheap and accurate.
Then you need some kind of microprocessor. A pic or OOpic.
The circuits are dirt simple. The senders are hooked up to the pic.
Programming this thing and outputting the info to the display are the problems. If you can do programming should be pretty easy.
Do a search for sensors or senders in pressure or temperature.
Or go to allied electric and search.

This link shows the basic idea. Just doing temperature and pressure should be pretty easy.
The microprocessor stuff can be found following robot links.

If you don't know programming then there are gauges for sleds and aircraft that will do this too for a proper price. Digitron, racepak, .http://www.grtavionics.com/ does all engine info on a single display, you probably only need the 2002 model.


New member
Everything you mentioned is available on the diagnostic port (all cars 96 and up). If you buy the HS-3000 manual from SAE it will have everything you need to know.


New member
You'r use OBDII port in your automobile. OBDII port is CAN bus.

sample here > http://patriot.net/~bmcgin/automobilediagnostics.html

This page can't help you, you'r use a microcontroller who have CAN bus. For example www.microchip.com same microcontrolers have can bus.

look this page

and this page is app Not pages
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