Your own ODB

**getyours_2006** · 08-29-2006, 04:49 PM

I'm busy with a little project sinds ODB is no option for the most of us and when it is does it work etc etc etc.

Al the measure points in a car are sending signals. These signals can be measured.

The only thing we need now is a skinner and a programmer.

Sinds al cars have there own diagnostic all info is welcome.

the following things can be measured

- engine preformance in rpm
- speed in rpm
- petrol level in %
- oil presure in bar or psi
- oil temp in celsius
- oil level in %
- water temp in celsius

The i/o measures volt or ohm Ω the current in a car is 12 volt.
When you have a full petrol tank Ω wil be X

So in an tabel would be something like this

level Ω

100% = 10
75% = 20
50% = 30
25% = 40
0% = 50

Next thing to do is to buy everthing I need.

Everthing in the car is already there, only the oil pressure switch has to be changed for a oil pressure transmitter

an i/o put card en some software

the hard wil cost me 40 euro software is free.

**Sonicxtacy02** · 08-29-2006, 04:55 PM

i coulda swore this thread was gonna be about old dirty bastard

**getyours_2006** · 08-29-2006, 05:00 PM

lol

**Jirka Jirout** · 08-29-2006, 06:03 PM

Originally Posted by getyours_2006

The only thing we need now is a skinner and a programmer.

I am afraid it is not that simple.

- Rpm is typically a square pulse signal (output from Hall sensor), so you cannot measure it as a resistance - you have to count pulses.

- Same for the injectors to measure the fuel flow (there you have to be careful about input if you do not want to destroy the switching element in the ECU that controls the injector).

- Same (mostly) for the distance information which may be quite useful - this is also pulse-based signal (1 pulse per 25 cm in my case).

- The fuel level does not have to be a resistance-based sensor. Capacity-based sensors are pretty common too.

- Not all cars have the oil level sensor.

the hard wil cost me 40 euro software is free.

There ain't no such thing as a free lunch. The time of the programmer (and yours) is certainly not free, is it? ;-)

A good hardware could be the Conrad C-Control II application board. It has some binary inputs that you can use for counters, A/D converters (for measuring the resistance/voltage), RS232 (so you can communicate with the computer) etc. It is available on http://www.conrad.nl, but I think it costs a bit more then 40 Euro.

**Scouse Monkey** · 08-29-2006, 06:36 PM

take a look at the porsche 944 linux install. he made his own sensor interface.

I see you have a 306 as well (still trying to get a screen in mine). the best way is going to be to interface with the dash for the rpm and speed - vss is actually very easy to hack into and get a decent result from and rpm is just as easy.

for your temps you can splice into the original senders or you can even add your own for gearbox etc etc by fitting new sump plugs with temp sensors built in.

I know a little more about the 306 than most people so give me a shout and i will see if i can help.

**getyours_2006** · 08-29-2006, 06:49 PM

Originally Posted by Scouse Monkey

take a look at the porsche 944 linux install. he made his own sensor interface.

I see you have a 306 as well (still trying to get a screen in mine). the best way is going to be to interface with the dash for the rpm and speed - vss is actually very easy to hack into and get a decent result from and rpm is just as easy.

for your temps you can splice into the original senders or you can even add your own for gearbox etc etc by fitting new sump plugs with temp sensors built in.

I know a little more about the 306 than most people so give me a shout and i will see if i can help.

This are the responces I'm lookin for .

Sadly there more people who like to talk
about what is difficult and what cant be done but when its out there they are the first to use it.

So please only respont if you want to help figour this thing out

**getyours_2006** · 08-29-2006, 06:55 PM

Originally Posted by Jirka Jirout

I am afraid it is not that simple.

- Rpm is typically a square pulse signal (output from Hall sensor), so you cannot measure it as a resistance - you have to count pulses.

- Same for the injectors to measure the fuel flow (there you have to be careful about input if you do not want to destroy the switching element in the ECU that controls the injector).

- Same (mostly) for the distance information which may be quite useful - this is also pulse-based signal (1 pulse per 25 cm in my case).

- The fuel level does not have to be a resistance-based sensor. Capacity-based sensors are pretty common too.

- Not all cars have the oil level sensor.

There ain't no such thing as a free lunch. The time of the programmer (and yours) is certainly not free, is it? ;-)

A good hardware could be the Conrad C-Control II application board. It has some binary inputs that you can use for counters, A/D converters (for measuring the resistance/voltage), RS232 (so you can communicate with the computer) etc. It is available on http://www.conrad.nl, but I think it costs a bit more then 40 Euro.

software is free because you have to wright is your self and it's comes with the hard ware. I'm a junior proces enginer in chemistry so I know a little bit about
measering and if it already worked for others than it has the work for us also.
The only thing I want is to see it in roadrunner or freeway