I have been seeing a lot of discussion about low oil pressure alarms. It is a great idea. I just couldn't find anything I liked that did what I wanted. I guess I just wanted too much. Well, I finally came up with a system I liked but cost much more. I started with a micro controller that could be programed, can read dc voltages, etc. Designed some input circuits that would handle the 0 to 14V signals from the sensors. I wired it up to the oil pressure sensor, temperature sensor, fuel level sensor, battery voltage, and in my case an oxygen sensor. Integrated a 16x2 display, error light, buzzer and 2 switches. What I have now will monitor the oil pressure, temperature, voltage, fuel remaining, and fuel mixture. The error light flashes, and the buzzer buzzes 3 times if an error occurs. It delays errors for about 10 sec after the ign is turned on. The error levels can easily be adjusted to any thing you like. For instance now I have oil pressure set at less than 5 psi, temp at more than 212degF, voltage atless than 11.5V or more than 15.5 and fuel level at 1 gal remaining. If there is an error, the display shows which reading is bad. It even points at it with an arrow. In other words, if the alarm goes off, just look at the display and it will show you what the problem is along with the current reading. Oil and Temp are shown together, Voltage and Fuel together and O2 and some test data that can be changed are shown together. The O2 will not cause an error and the low fuel will only flash the error light but not the buzzer. One of the PB switches select the display page and the other resets the error for a few seconds and then beeps and displays the error if it is still present.
I have about $100 dollars and many many hours invested in it.
The first question I will answer is: No I won't build you one. I will however give you diagrams, programs, or anything else I have that you may need if you would like to build something like it. I will try to help in any way I can. This is not a project for some one who doesn't understand some electronics and computers but for people like me that enjoy building things like this and want to do it yourself. I know there are a lot of people out there that can do this, and do it better than I. Maybe someone would like to design a printed circuit board and make it available if someone wants to do something like this. That would make it a lot easier to build. Other things could easily be added or removed or changed.
What do you think?

Paul

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84 500 SEL (307,xxx miles)