Gauge Cluster Digital Integration

[aacordon]

Hello All.

I am currently a Electrical Engineering major specializing in control systems and micro controllers. As a way to test out of two upper division classes my professor and dean is allowing me to create a digital integration project.

My plan is to integrate the gauge cluster of my eclipse (Analog/Eprom based) with a micro controller, which will allow for a digital output of mileage and trip meters, LED lighting with color representations for warning (Rev limiter, start up, warnings etc...). I just needed some quick info as this is a bit more advanced then most search results on the forum.

Since I do not have access to an oscilloscope to use on the car, I need to know the output of the speed sensor ( Gear type Hall effect sensor ) used on the transmission of a 2g gst/x, and the tachometer. With that information I would be able to take that as an input to my controller and manipulate it to do complete all of the above tasks.

If my plan works out I will try and make a write up of it.

Any info would be helpful, as I am currently creating the schematics for all the circuit boards on the cluster.

Edit: Title: gauge misspelled

 

[knochgoon24]

Integrate it with the OBD2 port. It outputs hex code which should be real easy to deal with. There's a lot of info on the web about OBD2.

 

[aacordon]

Thought about the obd2 port however the professor wants me to tap into the outputs from the speed sensor and the tachometer directly and keep it as an all in one unit which can be removed for testing and emulation purposes in a lab.

 

[knochgoon24]

At least you can test your readings with the OBD2 port and calibrate your microcontroler. Could you possibly use the mic jack on a computer with a resistor to bring the voltage down? Since the car runs on DC, you'd see the pulses in voltage, not frequency (as long as the output is analogue).

DISCLAIMER: I'm not an electrical engineer, it's just a hobby of mine. I don't guarantee any idea of mine would work. I'm not responsible for frying your sound card or any other part of your computer.

Here are a few links that might help you out.

http://www.geocities.com/lptscope/
Oscilloscope for the Soundcard
Visual Analyser 10.0.5 NE
Buffer Hardware for xoscope

This is the cheapest form of an oscilloscope I found while searching for info.
Parallax USB PC Oscilloscope

Hope something there helps.

 

[aacordon]

Thanks for the info. I will be using my logger along with gps to calibrate, and I believe I figured out how to obtain the readings i need. The input of the cluster goes to an eprom which contains the voltage map for the pulse width from the sensor. The eeprom then acts as a frequency to voltage converter to have a linear dc output. I just need to create a simple (low load) buffer circuit to take those readings and use my controller with it. I can then use the ADC on the controller with a math equation to output the speed and rpm's accordingly.

It will then only take me minutes to write the code to run as many LEDs as I need because I can use shift registers and a clock to increase the number of outputs from the controller.

I will be ordering parts tomorrow since I will not have access to my school supply room until the 25th. Wish me luck.