Hey people,

I would like to build a datalogger that is based on the arduino. The unit will have an onboard SD Shield such that I can save information for viewing later. I also would like to write the information to an LCD screen. So I can see the information instantly.

I've been doing some searching and found that someone hase done something similar. Below is a video. The reason for making this thread is to ask you guy this. How do I go about reading the information from the 4 pin header connection on the ecu. Theres only 4 wire leads at that connection but we are able to see so much information like RPM SPEED MAP IAT and even ELD voltage. How do extract the bytes of information from these 4 wires? Thanks for reading

 

I haven't looked into this myself (been out of the car thing for a while now) but I know a very little about the arduino's, so maybe I can help point you in the right direction.

The ECU (depending on the model) will have some sort of "communication" capability. Older ECU's will most likely use some form of serial communication or TTL, newer ones are more than likely to support CAN bus (your arduino will need a CAN shield for this).

Once you can communicate with the ECU, you can "read" any of the parameters that the ECU has available (RPM, TPS, Water temp, Intake air, ground speed, ect, ect.).

Once the arduino has "read" the parameters, you will need it to send it to the display and store it on the sd card.

Depending on both the SD shield and the display shield, their communication protocols can vary so it will be dependent on the gear you choose.

While you are at it, you could add a IMU shield (3-axis gyro + 3-axis accelerometer) to measure g-forces. Which can then be converted to cornering/accelerating force and even calculate horsepower

 

I'm also working on something with this. I ended up getting sidetracked for a few months though because I needed to build an engine sim to figure out the protocol for my setup.

Now that that's almost ready to go, I should be back to working on it soon. My advice to you OP:

-Start small. Try and get some data from the ecu, then work up to building your LCD, then maybe an mpgduino type device so you can get a hold of making it do math and combine inputs.

-look into a 32 bit platform such as the due. You'll find you run out of processor pretty quickly when you start trying to handle multie inputs. I'm expecting to end up moving up to something like the raspberry pi pretty quickly and I've hardly scratched the surface

-The GUI for using the data is the next big limit. Just about anything can store big stacks of data bits. The software offered by the commercial data logging companies are what make it useful but are proprietary. You can still do a lot with matlab or mathcad or even excel though if you are inclined in those areas.

-Read some books on logging and vehicle dynamics. I recommend the one by Simon MacBeath if you're just getting your feet wet.

-Prepare to be addicted. Programming is fun once it all starts to gel

 

Thanks guys for your response.

I bought this book called arduino workshops which has been introducing me to some of the different projects that use the arduino.


And I also bought this book called Make Electronics


I bought these books so that I could gain a better understanding of Resistor Capacitor (RC) circuits, Integrated Circuits (IC) and (TTL) Transistor Transistor Logic, but I am still learning.

Back to the original question though: I believe the ecu uses SPI Serial Peripheral Interface to communicate out of the CN2 port but I'm really not sure. I am able to read the 0-5Volt signal from variable resistor sensors like the MAP sensor and TPS but what I'm doing is just reading the voltages from the signal wire before it even gets to the ecu. For me to read from the CN2 port I think there is alot more magic that needs to happen. I think all other sensor information is sent in little packets of data but I am unsure how to recieve and organize this information.

 

There is a ton of good info for you to read here:

http://www.d-series.org/forums/engin...-dash-lcd.html

Start picking around at pgmfi.org as well. It's not nearly as busy as it used to be, but there is a ton of useful info on that site.

 

You'd need the protocol for the management on the chip that you're trying to log from. Crome has theirs available on pgmfi.org, at least the older versions.

 

Thanks spAdam

 

Thanks to you too HRTuning. You must not sleep man cause your always answering my questions.

 

lol. I sleep very little and always make time to check the forums.

 

I'm working on a prototype right now.
So far I have only gotten my LCD to work correctly and still programming the rest of the interface. All i can say is build slow and go from their.
I opted out of the 2 color LCD and went for a 16bit colored LCD.

 

When are you going to release yours?

 

I have a lot of things coming. How soon... unknown

 

hmmmm interesting

 

James, what ever became of the Proefi collabo you mentioned a while back?

 

PM