computer project

n.mulvana N.Mulvana at
Tue May 23 14:42:48 GMT 1995

Hi to everyone on this list.
I'm new to most things to do with the INTERNET so please bear with me!
I have read with interest the articles posted to this list which prompted 
me to post some details of a project I have almost completed for my car ( 
a 1991 FORD).
I decided I would like to design a fuel computer which looked and worked 
as much as possible like the computers fitted to the higher specification 
versions of my car.
At first I thought I would have a problem obtaining and fitting the speed 
and fuel flow sensors which were very expensive as off-the-shelf items, 
but on examining the schematic diagrams for the car I discovered a speed 
pulse train which is fed into the EECIV management computer and a fuel 
pulse output intended for diagnostics and fuel information for the higher 
spec cars.
The fuel level was the hardest information to sort out because of level 
fluctuations with acceleration/deceleration and gradients, I have almost 
sorted this out now by doing some sophisticated averaging in software!
I have fed four inputs from the door ajar switches and created a nice 
little car graphic on the LCD display to show if doors are open I have 
also incorporated an external temperature probe and a connection to show 
battery volts.
All info is read by using just two buttons as well as being able to reset 
fuel used and average MPG
I have used the user-defined character capability on a 20x4 LCD display 
to produce characters 3 (5x7) chars high by 3 (5x7) chars wide so the 
display is very easy to read!
I used a 80537 microcontroller and wrote all the code in C.
I hope my ramblings make interesting reading to SOMEBODY, if anyone would 
like any more details please feel free to email me.
n.mulvana at

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