OBDII from scratch.... No vehicle ECU

**pdnz** · 03-15-2012, 02:21 AM

Hi all,

This is my first post and I am currently building a classic Mini from scratch and have had my eye on this forum for a long time. My plan is to build the mini such that from outside of the car, the classic nature is kept, however, once inside the car, it will be very digitalized. No gauges etc... Just screens and touchscreen buttons... I am yet to decide on hardware etc but I am thinking of running Centrafuse. I would like diagnostics etc but obviously the car has no sensors / ecu / OBD plug so my question is as follows:

Is there something that explains how OBD is communicated? I can make an embedded board with my own sensors measuring all the data but I am just not sure how to program it such that it outputs OBD commands that would be recognisable by any OBD sensor and hence work with Centrafuse.

Has anyone done anything like this before? I have tried searching but I don't really know what to search for so it hasn't turned up much

Any help would be hugely appreciated!

Thanks!

**p2psmurf** · 03-15-2012, 01:42 PM

To get any respons on the data you would need a can-bus.
Are you a senior hardware engineer and a senior software engineer espicially with embedded software?
When no, I would look into other possibilities.

I would convert the engine to take an aftermarket ecu.
I would use a Gems programmable after market ecu and a Gems programmable dashboard.
Gives you multiple pages of data, but still has the old knobs, I am afraid.
The disadvantage is that GEMS is difficult to map.

Maybe Motec is an alternative. have a look here: http://www.motec.com/products/productoverview/

**SNOtwistR** · 03-15-2012, 02:32 PM

I think fusion brain or phidgets would be your best bet since you could tap into the sensors that are on the car already you won't get much from the old mini motor but you could get coolant temp, oil pressure/temp, volts, amps, not sure on rpm as you would need to tap into a tachometer to get the signal. And both those boards have CF or RR support. just a thought SNO

**pdnz** · 03-15-2012, 03:16 PM

I'm not a senior engineer no but I do have experience with embedded systems and programming them. I was planning to install my own sensors around the car to measure anything I want (RPM, temps, volts etc etc). I would then build an interface based on a microcontroller. These sensors will be plugged into my microcontroller interface which will read all of the sensors.

I figured OBDII is technically just a communication protocol so surely if I can program my microcontroller to output the data from the sensors in the same format as OBDII then any computer would just think it is receviing OBDII signals and read it just fine. I've got a microcontroller built up that reads sensors and sends the data via serial to a PC.

I know the mini doesn't have many sensors but I will be installing my own.

Any thoughts?