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Making a Color LCD Dashboard Replacement?
DarkHand asks: "I've recently begun a project that would allow me to replace the analog gauges in my cars dash with a TFT LCD screen displaying a digital representation of the same. A number of animated analog-looking gauges would display the same information the physical gauges display, based on info from the ECU, as well as any other information the ECU has access to, such as intake air and coolant temperatures, throttle position, pop-ups for any warnings or error codes, etc. I'm looking to be able to add, remove, and customize the positions of the individual gauges, and possibly even make the background skinnable. Stability is crucial, so I'm leaning toward a Linux-based system. I have a few software friends who are willing to help on that end, but finding the proper hardware for such a project has proven difficult."
"I need something that either boots within a few seconds, or draws very little power when idle so as to remain active and run off the cars battery. A laptop or small computer boots too slowly, and draws too much power to stay on all the time. A high powered PDA with a larger screen would be perfect, but as far as I know it's not possible (or at least not easily doable, both in hardware and software) to change out to a larger display. The best option I've found so far is the venerable Gumstix board, but as far as I can tell, LCD support is still shaky. Has a similar homebrew project been done before, where I could go for wisdom? What kind of hardware would the Slashdot crowd use in such a situation?"
his not going to rely on _controlling_ the car on linux, just showing some variables.
standard speedometers already suck by default, they are not that fast to respond, nor very reliable, and wouldn't really be that dangerous to be shown by a pc. they're already shown by a computer built on a shoestring budget anyhow(seperate from the systems that actually control things like abs brakes and stuff that _really_ matters).
you can always stop you know if those meters stopped functioning, if you couldn't then you're already driving too fast.
world was created 5 seconds before this post as it is.
I googled 'OBD II' a while back and found these:
t m
http://www.obd-2.com/
http://www.ghg.net/dharrison/obdscan.html
http://www.obdii.com/ubb/Forum1/HTML/000359.html
http://www.andywhittaker.com/ecu/obdii_software.h
http://www.elmelectronics.com/obdindex.html
http://www.dynahud.com/default.asp
They should get you started...
Leaving a computer in the cold weather might also be a problem, and LCD's have a noticably slower refresh rate in the cold.
Make your computer faster: rm -rf
http://www.arcom.com/pc104-xscale-viper.htm
Some of those thingies running embedded Linux might do the trick. Just attach it to the car's computer via USB or serial cable. It has its own LCD controller and can run embedded X windows even. Then writing the software is relatively simple.
The GeekNights podcast is going strong. Listen!
You might consider one of these
From the site:
SIS 55x processor (x86 compatible)
3 USB ports
2 Serial (RS-232) / 1 Parallel port
Built in AC97 audio - Audio in/out
2 VGA out ports
ATA-33/66/100 support
1 or 2 RJ45 for 10/100 MBit Lan
PS/2 Keyboard/Mouse connector
Single 5 Volts DC @ 1.8 A support
128 MB RAM
20 GB 2.5" hard disk
1 NTSC or PAL video in (frame grabber)
1 NTSC or PAL TV out
Support for two VGA displays
I've been looking at doing a project like this for a while now, so I'd be interested to see how you go about some things.
I've chosen to install analog speedo, tach, H2O temp and oil pressure. This allows the LCD screen to be less expensive and less important so I don't mind as much when it's unreadable (say, a cold start at 0 degrees).
:)
Even with a good (transflective or super-bright backlit) screen, you'll need to ensure that it is shaded well against light from an oblique angle. Depending on your dashboard, that might be easy or it might be hideous.
Right now I'm thinking I'll gut an IPAQ H3950 running Linux to supply the display and controller. Apparently it has a good screen, and I'm sure it's rugged enough for automotive use. The battery will help a lot too. The one drawback that I can see is the screen is only 320x240. I yearn for 640x480, but I've been unable to find aything daylight readable in that resolution for less than a few thousand dollars.
How to interface to it? Wifi!
Be sure to check out mp3car.com. I'm currently installing a PC in my car that will have an OBD-II interface. The forums there will probably be able to help you with your hardware and software selections.
Actually, LCD's don't really have issues like that at the moment. Check out the Pioneer AVIC-N1. Its a DVD player that hooks into the vehicle and will display the gauges, just like the story parent wants. Its possible, just a matter of making it work from scratch.
I'm doing this myself now. I'm still in the early stages but have most of the parts. Just need to pick the computer itself and the power supply. (Probably go Opus with a ITPS)
;)
:)
It's definitely going to be linux. I think I'm going to just put a half tower in the trunk as I'm going to need a lot of expansion cards.
I'm leaving the gauges in place and putting the monitor (lilliput 8" touchscreen) in front of it and wrapping it up in custom fiberglass cowel.
My wiring passes through the gauges into other systems, for instance the battery charger so it's easier to leave everything in place and easier to just remove screen and replace with stock cowel for inspection time.
For the harddrive, I'm using a ruggidized harddrive designed for automotive use. Slow but it's got a great temperature range and shock rating.
The keyboard I'm using is a tiny one I found on ebay. I cut it down to fit in a 1 DIN position. It fits between the stock radio and AC controls. You don't know it's there when retracted.
Most of the inputs will come from OBD-II (elmscan that I embedded inside floor) but it's not fast enough for the tach and speedo. (4 samples a sec at beast ISO) I'm tapping the tach, speedo and a few other input signals directly and processing them with a PIC. The PIC will then communicate with the PC via serial.
I'm thinking later, I'll add a large commodity drive for other non essentials that will be activated via a temperature controlled relay. So if it's under 40F in the trunk, it won't power the harddrive until it is hot enough or maybe I'll just use a USB drive.
My first advice is to buy the factory service manuals on ebay. They are invaluable. I got mine for $40 US. Three phone book size volumes with schematics as well.
You might find the factory training books for the electrical and whatnot as well. I did. It was nice to have the whole ECU protocol detalied. (Though not planning to tap into it at this point)
If possible, buy extras of whatever your going to mod on ebay. For most parts I'm fooling with, I have 2 or 3 extras that I've amassed over time. If your patient, you can get stuff cheap.
For instance, in my spare room, I have a spare dashboard, gauges and most everything else on the dash. I'm using this to work on the fabrication so I don't have any downtime (or screw up my car)
$1700 dollars worth of stuff righ there. $240 shipped in mint condition. Patience is the key.
As far as the legality, I'm not concerned. If I had a massive failure, the only thing that I would be missing are my current speed, engine rpm, fuel and oil temperature. Nothing that would ever cause a crash. I can estimate the first 3 fairly accurately. Certainly enough to safely pull over and remove the screen and use the OEM gauges. A fuse could do the same thing to the OEM gauges (and has to me before)
Besides the fact that I'll have more readings on my car (which will actually improve safety), In phase 2, I'm going (try) to tap the ABS wheel speed sensors. By using the four sensors, I've now added differential tire pressure monitoring to my car.
My whole design goal is to have something integrated, yet I want it stealth. If you walked by, you'd have no idea it was anything special. You might if you were astute, notice the monitor, but you would probably just mistake it for a regular an OEM readout.
A great site (Australian cars though) for technical car info and ideas is Autospeed.com.
There is some other stuff, but I'm not going into detail until it's done
-William Shatner can be neither created nor destroyed.
Free RTOS has an open source RT kernel as well as some handy dandy how-tos and technical resources.
R(k)
I forgot to mention in the article that this would be for an autocross/track car, so legal issues aren't a problem. Sorry about that. :)