I'm not sure if this would be better off tackled through a micro-controller or a series of gates and analog building blocks but I'm looking for some direction.

I want to take a series of sensor ohm reading measurements (referenced to ground) and if they read zero or close to it I want to give an on signal output for that particular sensor.

After this I'd like it also to go through an OR Gate (or NOR) and be output to a main output.

Would I be better off using a micro-controller?

If not and I go old school logic what would I use to pickup the sensor's ohm reading outputs.

I guess to complicate things a little more, sometimes the ohm reading will be a range and a certain range will output a ONE or ON condition. I've used microcontrolers before and it seems like the analog ins work great for programming a range. But if I go the logic chip route, what part would I use to sense the range of ohm readings that are acceptable?

 

What's your supply voltage?

 

What's your supply voltage?

It will range from 10 to 14.5 volts d.c.

 

Like I told you before, we don't support automotive projects anymore - for good reason.

I appreciate your dilemma. Please appreciate mine.

And I'll give you a little personal story of my experiences with automotive modifications.

I'm not an automotive engineer.

However, I've worked on fighter aircraft like the F-4, F-14, F-15, F/A-18, F-22, and a number of others in engineering, manufacturing, and operational maintenance capacities.

I used to have a 1988 Jaguar XJ-S V12 convertible; the conversion was performed by Hess & Eisenhardt under authorization from Jaguar Cars, Ltd.

The vehicle was beautiful, but there were a great number of engineering shortcomings, far too numerous to expound upon on this forum.

I enthusiastically embarked upon making quite a few modifications to it; a good number of them were successful, and some were not. Keep in mind that at the time I was making these modifications, I had been certified to work on military aircraft (even spacecraft), and had nearly 30 years of electronics experience under my belt.

The systems in the 1988 Jaguar were relatively low-technology compared to more modern automobiles. I had problems with some modifications despite my level of experience, even when I used components/materials that were above what should have been required.

What I'm trying to do is to save you from yourself.

If you start trying to "tap in" to the more modern engine control systems, there is no telling what you are going to run into.

Currently, my spouse and I have three vehicles, and they are completely stock - except for two of them have trailer wiring harnesses and hitches, that were installed by licensed dealers. We seldom have problems with the vehicles.

I can only suggest that you are trying to protect against eventualities that very rarely occur, unless one is negligent to the extreme on maintenance.

Oh, and automotive electrical systems might typically be in the range of 10v to 14.5v - but during load dumps (like when you switch the lights off) - the system can exceed 60v for a few moments.

Making changes to autos is not a safe place for amateurs to dabble in.

I know you mean well.

If you wish to get that kind of experience, get an EE degree from a respectable university, and then work for an auto manufacturer for a decade or two. Then you'll have an excellent idea on what to do - or at least understand how much there is that you don't know.