I always have hated it that my vehicles don't have any sort of warning for major problems such as:

All the oil leaking out due to a burst oil cooler hose and having the engine run miles without oil before it locks itself.

That's obviously the worst case scenario. But there are other major things that could also be a big problem. So here's my project.

I'd like to make a logic structure to sense the following and give an alarm (buzzer and bright red LED) if the conditions are not met. Here are my conditions and sensor outputs:

1. Oil Pressure - Must have Zero Ohms across sensor (to ground)
2. transmission fluid pressure same as above
3. coolant pressure same as above
4. Transmission Fluid temperature - need to calibrate for this sensor's output but the ok range is from 100-200 F and the sensor will give me an ohm value to ground.
5. Fuel Pressure-gives an ohm output that's meant to to to a gauge but I'll be using it to give a reading to a comparator.

So my thoughts on this are a few different routes:

A. Old school logic (comparators and gates)

or

B. Micro-controller that will be able to have inputs and do all the processing and output to the LED/Buzzer in one chip.

What is going to be the easiest way to go about this?

As far as the specifics, are there common parts for either A or B that will work well?

thanks in advance for the help!

 

You would have to use secondary sensors for each alarm, for you would not want to cause a problem with the ecu or any stock system.

 

You would have to use secondary sensors for each alarm, for you would not want to cause a problem with the ecu or any stock system.

This may be true. I would think if the inputs on my setup were high enough impedance they would have little effect on the existing ECU readings. But that said, most stock vehicles will need to have simple sensors added in to get readings on various things.

 

Point is, you dont want to touch the stock system. The safety issue and insurance issues are the biggest point.

And any interference you place on the ecu sensors could change a number of variables like air/fuel mixture, and coolant solenoid valve actuation, etc. So, staying away from the stock system would be key.. And the sensors are cheap enough, and would allow you FULL access to them without having to worry about the ecu's reaction.

 

Hello 7877funk,

I'm sorry, but after long and careful consideration by the Board staff members, a decision was recently made to prohibit all discussions of motor vehicle related projects on this board.

This is due to the real safety hazards and potential legal issues that may be involved when people who were not specifically trained as automotive electrical engineers make recommendations for people who are not specifically trained and certified to build and install automotive-type projects.

The only recommendation that we can make is to have your motor vehicle professionally maintained just as it was originally configured when delivered by the dealer, as at that time it was in compliance with all safety, transportation department regulations and emissions laws.

This policy may sound a bit over-restrictive, but it was the only logical decision that could be arrived at. I am not a member of the staff here, but I wholeheartedly agree with their decision.

 

Hello 7877funk,

I'm sorry, but after long and careful consideration by the Board staff members, a decision was recently made to prohibit all discussions of motor vehicle related projects on this board.

This is due to the real safety hazards and potential legal issues that may be involved when people who were not specifically trained as automotive electrical engineers make recommendations for people who are not specifically trained and certified to build and install automotive-type projects.

The only recommendation that we can make is to have your motor vehicle professionally maintained just as it was originally configured when delivered by the dealer, as at that time it was in compliance with all safety, transportation department regulations and emissions laws.

This policy may sound a bit over-restrictive, but it was the only logical decision that could be arrived at. I am not a member of the staff here, but I wholeheartedly agree with their decision.

Thanks for the heads up. Could you point me to a link with a little more regarding this rule on the forum?
thanks!

 

It's covered in this thread:
http://forum.allaboutcircuits.com/announcement.php?f=6&a=3
Forum Rules, Code of Conduct and Terms and Conditions of Usage

Subheading:
Rules, Code of Conduct and Terms and Conditions of Usage:

2. Appropriate conduct. Forum members are responsible for the content of their posts, including information they provide, validity of this information, and any extra content they may append to the post.
(snip)
Forum members must not knowingly provide any information that may adversely affect another member; this includes, but is not restricted to, information that may potentially result in injury, death, damage or destruction of property and possessions. The administration takes this matter seriously and has the right to remove any contentious content and deal with the offending member as it deems is necessary.

 

Very few (if any of us on the forums) are professional automotive engineers.

Even someone was, they probably don't have an exact version of your vehicle available to analyze all possible ramifications a modification might make.

The other part is on your end; the condition of your vehicle and your level of abilities are an unknown. If you were a certified auto mechanic that might be OK, but you would need to be installing something that had passed through the engineering team for the vehicle in question.

I've made some mods in the past, and they didn't always turn out well. The best thing to do is to leave your vehicle as it was delivered by the dealer, and follow the recommended service intervals using a mechanic that's trained and certified.

 

It's a policy issue that AAC has started to enforce. We have no means of determining the quality of work or the local and/or national permissibility of the alterations.

Even when done by a licensed shop, not all outcomes are good - http://machinedesign.com/article/truck-fire-started-in-wiring-bundle-0406

 

My dad once bought a lemon of a Range Rover that someone had replaced the petrol engine with a diesel engine that wasn't designed for it. Apart from the fact that it could only do about 60mph because the gearbox was the original and the diesel reved a lot slower, the main problem was that it caught fire in a supermarket carpark for some unknown reason. Announcment on the tannoy "Will the owner of the Range Rover please go to the car park because it is on fire".
Happy days.

 

When I was a youth, I worked for Home Depot. I remember one day hearing:

"Would the owner of a brown late model Volvo please report to the parking lot, I don't have the license plate number because it is on fire. Thank you."

Apparently he painted his brake rotors with regular spray paint and they caught fire while he was in the store. I think they were smoldering and a breeze just happened along at the right time.

 

Well, more examples only serve to reinforce the point. An automobile has to be able to operate safely while in close proximity to other automobiles.