# car instrumentation

K

Jan 1, 1970
0
I'm toying with building an instrument panel for my car.

Basically, a LCD display about 6" x 1.5" which would show things like oil
temp/oil pressure, coolant temp, tranny temp, battery voltage (and
possibly draw with the use of an appropriate shunt), outside air temp,
etc.

I would guess that someone out there has done something like this. I
figure I need something like a very basic CPU, output of some sort to
drive the LCD (serial? video?), and a mess of A/D converters. Or perhaps
some other way of doing this?

I'm not looking for a full package like the race cars use, just something
better than the idiot lights on my car, something useful with a high
'cool' factor.

TIA,

-Kamus

J

#### JeB

Jan 1, 1970
0
I'm toying with building an instrument panel for my car.

Basically, a LCD display about 6" x 1.5" which would show things like oil
temp/oil pressure, coolant temp, tranny temp, battery voltage (and
possibly draw with the use of an appropriate shunt), outside air temp,
etc.

I would guess that someone out there has done something like this. I
figure I need something like a very basic CPU, output of some sort to
drive the LCD (serial? video?), and a mess of A/D converters. Or perhaps
some other way of doing this?

Probably just one A>D on your cpu ... then a method to switch between
sensors. The sensors to work with it are probably the challenge. The cpu
I'm not looking for a full package like the race cars use, just something
better than the idiot lights on my car, something useful with a high
'cool' factor.

I don't understand why no one is manufacturing something like this.
There are bicycle computers in the $10-20US range that can do everything but take out the garbage. A single display with the ability to select a given input or simply scan all sensors would be fine. I'd like the basics: oil pressure, coolant temp, voltage, but being able to add the other "wish list" items above later would be good and a source of further income for the manufacturer. - jim K #### Kamus of Kadizhar Jan 1, 1970 0 JeB said: Probably just one A>D on your cpu ... then a method to switch between sensors. The sensors to work with it are probably the challenge. The cpu probably already has display drivers. Well, the idea is to display all the things you want to monitor, then, on alarm conditions, zoom in on the out-of-range items and light a single idiot light on the dash. The sensors are out there; basic high-quality resistance-type sending units are around$10 for temp, pressure, etc. Once you get into gear
shift indicators, air-fuel mix, etc. that runs into money.... I figure
a basic voltage divider using the run-of-the-mill senders should work.
I don't understand why no one is manufacturing something like this.
There are bicycle computers in the $10-20US range that can do everything but take out the garbage. A single display with the ability to select a given input or simply scan all sensors would be fine. I'd like the basics: oil pressure, coolant temp, voltage, but being able to add the other "wish list" items above later would be good and a source of further income for the manufacturer. Amen. It's so simple, that I don't know why someone hasn't done it. You could couple it with a GPS (you'd have enough CPU horsepower left over)..... J #### JeB Jan 1, 1970 0 Well, the idea is to display all the things you want to monitor, then, on alarm conditions, zoom in on the out-of-range items and light a single idiot light on the dash. I'd put this in the philosophical difference category ... I'd be happy with a single display and as mentioned, scan thru them as an option. And I'd probably want something audio if a real alarm condition existed. However, re-using a dash idiot light is not a bad idea. The sensors are out there; basic high-quality resistance-type sending units are around$10 for temp, pressure, etc. Once you get into gear

where do you find these?
shift indicators, air-fuel mix, etc. that runs into money.... I figure
a basic voltage divider using the run-of-the-mill senders should work.

i'm certain there are special purpose "embedded" cpu that have onboard
A>D, display drivers, etc.

K

Jan 1, 1970
0
JeB said:
where do you find these?

I'm sure there are others.
i'm certain there are special purpose "embedded" cpu that have onboard
A>D, display drivers, etc.

Where? I can't find any - except for industrial ones that cost .

Any pointers? I don't know enough about PC/104 stuff but that seems to
be the way to go. Still, it's damn near $1,000 for the computer, CPU, A/D card, and senders..... Cheaper than a blown engine, but..... Plus all of the programming.... There's some stuff I can adapt, but still.... -Kamus J #### JeB Jan 1, 1970 0 well beyond the$10 a pop range but at least they do exist.

ok ... i opened my mouth (er keyboard) without a specific device in
mind. Some googling and my first find in this category is:

Motorola Flash MCU with advanced LCD driver architecture

The 68HC908LJ12 MCU features 12K bytes of on-chip Flash memory as well
as the following

Liquid Crystal Display Driver capability for direct connection to a LCD
panel; 26 frontplane x 4 backplane configuration; 27 frontplane x 3
backplane configuration; 27 frontplane x 1 backplane configuration;
software programmable LCD contrast control Real Time Clock Module
second, minute, hour, day, day of week, month, year counters; automatic

100 Hz chronograph counter; alarm, and UART; Serial Peripheral
Interface; 10-Bit Analog-to-Digital Converter six (6) channels; 32 MHz
phase-locked loop

------
2002 news release suggests $4 each in large quantity. Where? I can't find any - except for industrial ones that cost . Any pointers? I don't know enough about PC/104 stuff but that seems to be the way to go. Still, it's damn near$1,000 for the computer, CPU,
A/D card, and senders..... Cheaper than a blown engine, but..... Plus
all of the programming....

this would likely be a very time consuming and expensive project as a
"one off". But you'd learn a lot, if inclined (or not ... a pretty
serious project including software) .

K

Jan 1, 1970
0
JeB said:
this would likely be a very time consuming and expensive project as a
"one off". But you'd learn a lot, if inclined (or not ... a pretty
serious project including software) .

Hah!

http://www.r2-controls.com/r2web/products/r104impala.htm

And the development kit is $99.... Sounds like this might do the trick - it's about the same price range as individual gauges.... C-programmable to boot. Anyone have any experience with these? Any other, similar one-board computers out there? Now to find a decent LCD display cheap.... -Kamus J #### JeB Jan 1, 1970 0 Hah! http://www.r2-controls.com/r2web/products/r104impala.htm And the development kit is$99.... Sounds like this might do the trick
- it's about the same price range as individual gauges....

C-programmable to boot. Anyone have any experience with these? Any
other, similar one-board computers out there?

I'm sure there are dozens to choose from.
The mag "Nuts'n'Volts" has or used to have a lot of advertisers in this
area. I think they have an online presence too. Probably a newsgroup on
embedded apps too.

I believe the Motorola unit could do the job and the 68xx series has
been around a long time so lots of development tools.

Now to find a decent LCD display cheap....

or u might want some sort of laptop type display if you want lots of
data viewable at the same time and u can find a suitable driver system.

R

#### ross

Jan 1, 1970
0
I don't know what type vehicle you are working with
but I am trying the same thing with a 88 Camaro
My plan uses the aldl connector of the ecm computer
I currently have two 486 75 mhz laptops (compaq)
that have been repackaged into a new dash display

Most sensors are already hooked up to the ecm
and can be displayed on a pc

currently car has mechanical problems so project is on hold
until I get it running again

C

#### Carlos L Qualls

Jan 1, 1970
0
I'm toying with building an instrument panel for my car.

Basically, a LCD display about 6" x 1.5" which would show things like oil
temp/oil pressure, coolant temp, tranny temp, battery voltage (and
possibly draw with the use of an appropriate shunt), outside air temp,
etc.

I would guess that someone out there has done something like this. I
figure I need something like a very basic CPU, output of some sort to
drive the LCD (serial? video?), and a mess of A/D converters. Or perhaps
some other way of doing this?

I'm not looking for a full package like the race cars use, just something
better than the idiot lights on my car, something useful with a high
'cool' factor.

TIA,

-Kamus
several part series on building your only digital dash for your car. If
anyone is interested I can scan the articles and post them somewhere.

Carlos

K

Jan 1, 1970
0
JeB said:
Motorola Flash MCU with advanced LCD driver architecture

The 68HC908LJ12 MCU features 12K bytes of on-chip Flash memory as well
as the following

Liquid Crystal Display Driver capability for direct connection to a LCD
panel; 26 frontplane x 4 backplane configuration; 27 frontplane x 3
backplane configuration; 27 frontplane x 1 backplane configuration;
software programmable LCD contrast control Real Time Clock Module
second, minute, hour, day, day of week, month, year counters; automatic

100 Hz chronograph counter; alarm, and UART; Serial Peripheral
Interface; 10-Bit Analog-to-Digital Converter six (6) channels; 32 MHz
phase-locked loop

OK, any ideas on where to find a ready-made controller with this as the
CPU? I've fished around google, and pretty much all I find is press
releases and marketing blurbs...

-Kamus

J

#### Josh K.

Jan 1, 1970
0
Unless I didn't see it... If your car was made in 96 or later (after 2000 in
EU) you have a diagnostic port. it works on one for 3 transmission types.
many people have kits, free online blueprints or sell assembled kits for
interfacing from car diag ports to serial ports. you'll have to do some
checking as to what your car supports but most support pressure, oxygen
sensors, temps and the like. Easiest and cleanest thing might just be to
use a small embedded PC or old laptop tucked away and just link your serial
through one of these small kits to the diag port. so Instead of being
invasive to the car's CAN network or anything just ask the computer in your
car!

It will tell you what you want to know. and if you ever get weird values
you can also use that info to troubleshoot your car for a failed sensor or
something is genuinely wrong! also you don't have to modify all those hard
to find plastic parts. I've seen entire kits with free software for under
$175! cables included. check them out... -Josh K. K #### Kamus of Kadizhar Jan 1, 1970 0 Josh said: Unless I didn't see it... If your car was made in 96 or later (after 2000 in EU) you have a diagnostic port. it works on one for 3 transmission types. many people have kits, free online blueprints or sell assembled kits for interfacing from car diag ports to serial ports. you'll have to do some checking as to what your car supports but most support pressure, oxygen sensors, temps and the like. Easiest and cleanest thing might just be to use a small embedded PC or old laptop tucked away and just link your serial through one of these small kits to the diag port. so Instead of being invasive to the car's CAN network or anything just ask the computer in your car! It will tell you what you want to know. and if you ever get weird values you can also use that info to troubleshoot your car for a failed sensor or something is genuinely wrong! also you don't have to modify all those hard to find plastic parts. I've seen entire kits with free software for under$175! cables included. check them out...

Josh:

That was how this started. The problem is size, power, cost, and time.

A PC104 chassis with a 386 CPU will run about $1000, with all the A/D stuff that I would need (the CAN network doesn't provide info like oil temp, oil pressure, etc.) Add to that the cost of the diag port to RS232 kit, Windows, and an LCD display, and you're bumping up against the$2K mark.

I just don't have the room for a laptop or a large display - I already
have all sorts of real estate taken up with other stuff (a 15" TV, a 5"
backup camera, a computer that plays movies, CB....)

Not only that, but now I have a PC that takes time to boot, and that
draws significant power (so I can't leave it on.) And that has a hard
drive that can fail (I just lost a RAID array over the new year's
holidays....)

So my choice is a tiny embedded MCU with a 4x20 LCD display. I figure I
can get two of those, with the sensors, for under $300, including the development kit. The only thing I won't get is a tach - a$20 MCU just
doesn't have the horsepower to keep up with a tach. So add $130 for a state of the art tach if I want one. Still a lot less than a PC104 chassis. Add to that that the MCU only draws 6ma - not not 5-6 amps like a laptop. So I can leave it on at all times.... And there's no boot up time. Sure, I have to do my own programming, but that's the fun part C #### Circuit Breaker Jan 1, 1970 0 Kamus said: I'm toying with building an instrument panel for my car. Basically, a LCD display about 6" x 1.5" which would show things like oil temp/oil pressure, coolant temp, tranny temp, battery voltage (and possibly draw with the use of an appropriate shunt), outside air temp, etc. I would guess that someone out there has done something like this. I figure I need something like a very basic CPU, output of some sort to drive the LCD (serial? video?), and a mess of A/D converters. Or perhaps some other way of doing this? I'm not looking for a full package like the race cars use, just something better than the idiot lights on my car, something useful with a high 'cool' factor. Any links, ideas, comments welcome. TIA, -Kamus Having read some of the other replies, and believing I understand what you are trying to do, would you consider using an already available digital dash if one was made for your car? I admit to not having read all the posts indepth, but I don't see you saying what kind of car you have. Judging by the CB, 15" tv, 5" backup monitor, etc. etc. etc., I'm almost inclined to believe you're driving a conversion van <g> Still, for many vehicles, digital dashes were simple direct-swap replacements, and you can probably pick one up at a good junkyard for anywhere from$15 to \$50, depending on the yard.

Just a thought. I know it wouldn't be homemade, but it would do most if
not all of what you are wanting to do. Only thing is that the odometer
won't be the same, but it should still work, and there's no need for bulky
interfacing or reprogramming of computer equipment.

HIH

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