DIY digital engine monitoring gauge set

[Krazyistkarl]

So I've started to cook up the idea of making a digital gauge to monitor engine oil temp, pressure and water temp, as well as trans temp and pressure.

I plan on using an Auber dual gauge for the LED screen as well as the +5V to power an Arduino board. The sensors will all be fed into the arduinos analog pins. Yes I could use a separate LCD screen, but that would complicate the coding, so at least to begin with I'll be using the Auber, which I've already got for my digital EGT and boost gauge. Why don't I include those sensors with this project you ask? Two reasons, 1) should this system fail, I still want those to be displayed and 2.a) although boost is a pressure reading, it uses a MAP sensor, which is different then an oil pressure sender. Yes, theoretically I could programmatically allow the arduino to modify the output scaling for the auber to pick up, but again that complicates the coding. 2.b) the EGT probe is a K type thermocouple, different then oil temp senders. Again, this could in theory be remedied programmatically.


I will include some rough sketches later using taptalk.

The function of the Arduino will be to continuously monitor all the sensors and watch for an alarm state, which will be programmed for each individual sensor and analog pin. It will then output the voltage using the digital PWM pins to the Auber gauge as an analog input (I'm not sure if this will work, I'll have to look up the resolution and sampling rate of the Auber gauge

I'll split the Auber gauges two "gauges" displaying Pressure and Temp, and by using the same sensors for engine and trans, the scaling will be the same for the Auber gauge to read.

I plan to have two momentary contact push buttons, one for pressures and one for temperatures as well as status LEDs to cycle which sensor is displayed on the screen. That sensor will remain displayed unless an alarm trip point is reached, then the Arduino will automatically output that sensors voltage to display on the auber.


I'll break it down into the two gauges on the auber, first is pressure. I'll go through a cold start up.

Start the van, Auber gauge will by default display oil pressure, the status LED will very quickly change from red to amber to green as it reaches pressure.
Push the pressure momentary contact switch to cycle to transmission pressure, status LED will display green, auber will read pressure.
You can cycle between the sensors at will.
If the pressure starts to drop within stage 1 alarm parameters the status LED will turn amber, until it drops within the set parameters for stage two and turn RED. The auber will display that sensor reading

Now temperature.

Start the van, auber by default will display engine oil temp (subject to debate, trans temp more important?) status LED will be amber until it comes up to temp, changing to green. Red is of course alarm
Push the temp momentary contact switch to cycle engine temp sensors and what the auber displays.
If a temperature climbs outside of normal operating range, stage one alarm will be triggered (amber status and auber display) if stage two is reached status LED changes red. A third stage alarm could as easily as adding a step to the ladder to Blink the LED.


That's a quick rundown of what I'd like the end result to be. The beauty of arduino is this gauge set can be changed rather easily, sensors added, adjust parameters, scaling, alarm set points. I can also run circuit mock ups and test for functionality on the computer, before physically assembling it. The arduino sketch can be edited on my android and connected via USB to the board and updated. It will also alow data logging of all the sensors and save it directly to an SD card.


What I need the forums help with are the operating ranges for the engine and trans and what my alarm set points should be, as well as where the sensors should be mounted.

This will actually be my first arduino project, but I like a challenge. I'm an industrial/mining electrician by trade with some instrumentation experience and a few friends who have worked with arduino before and are familiar with the coding.

[pluckmyeyeout]

Did you get anywhere on this?