OBD MPGuino gauge

[KJSatz]

If only shipping could be faster...but maybe the delivery truck is driving 55 heh.

[Magister]

For ISO I changed in the code the pin used, instead of using softserial on port 2/3 I now use the hardware UART on pin 0/1, I'll have to change this in the diagram, and maybe it will work better.

[RussEnterprises]

Originally Posted by Magister

For ISO I changed in the code the pin used, instead of using softserial on port 2/3 I now use the hardware UART on pin 0/1, I'll have to change this in the diagram, and maybe it will work better.

Hello, I'm new to this forum, I found this thread while researching another Arduino OBDII project I'm working on.

Has anyone gotten the code to work with ISO9141? Also, is the code that uses the hardware UART available? I just downloaded r110 from the google code page, and it's still using softserial...

I have an ISO9141 vehicle, I built an interface using the MC33290, but I'm having trouble getting the communication initialized. When the OBDuino code didn't work for me, I modified it to use the hardware UART on 0/1 and still couldn't get it to initialize. Then I started fresh on my own initialization routine using information from a variety of sources on the web. My code sends the 5 baud init on pin 1 using digitalWrite and the timings from prj.perquin.com, then initializes the hardware UART at 10400 baud and waits for data, printing anything it receives to the LCD. On my car ('99 Mazda Miata), the only response I can get is 5588, which is not what the obduino code expects. I don't have the official spec, so I'm pretty much shooting in the dark, but I've tried sending several different byte sequences after I get the 5588 but I never get anything else back.

I think my interface is working, since I am getting responses, and they are consistent. I'm planning to keep working on the problem, I just haven't had a lot of time lately. Any suggestions will be appreciated, and if I make any progress, I'll share it here...

Thanks,
Russ

[Magister]

R110 use UART, it uses serialRead() and serialWrite(), for the 10400 baud. (For the 5 baud it still uses bit banging, I don't know if the UART works at 5 baud?)

The answer should be 55 08 08 for ISO9141, maybe your car talks ISO14230?

Anyway as you receive 88, you should send ~88 as the answer, try it?

[RussEnterprises]

Originally Posted by Magister

R110 use UART, it uses serialRead() and serialWrite(), for the 10400 baud. (For the 5 baud it still uses bit banging, I don't know if the UART works at 5 baud?)

The answer should be 55 08 08 for ISO9141, maybe your car talks ISO14230?

Anyway as you receive 88, you should send ~88 as the answer, try it?

I'm fairly new to the Arduino, all the examples I've seen use Serial.read() and Serial.print(), so the serialRead() and serialWrite() confused me. I see now that the software serial functions are different.

I tried using the UART for the 5 baud, it didn't seem to work. I looked at it on a 'scope, and it looked like the bit spacing was 5 baud, but the bit period was much shorter, so I went back to bit banging.

I have the BR-3 interface and software for my PC, it IDs the car as ISO9141, so that's what I've been trying.

I'll try inverting the 88 and sending it back to see what I get. It may be a few days before I can try it, but I'll post results here.

There's a question that I haven't been able to find an answer to, maybe you can help... Once the UART is initialized, you can't use digitalWrite on pin 1. Do you know if there's a function to disconnect the UART without directly manipulating the control register? I discovered that if my init fails, I can't retry without reseting the arduino.

Thanks,
Russ

[Magister]

I don't think there is a function in wiring/arduino to disconnect the serial port pins, I guess you have to reset it, or re-send beginSerial(nnn)?

[Magister]

Ok, I received the MCP2515/2551, my interface works!

I made an init function to detect the CAN bus speed and the ID length used (11bits or 29bits) and it detects fine that my car is 500/11. I can receive message from the BUS, read them and display contents.

Now I will have to filter them, there's hundreds of message on this bus!

[knuckles904]

Originally Posted by Magister

Ok, I received the MCP2515/2551, my interface works

Glad to hear it. Cant wait for the schematic! Ive got myself a nice fat couple of projects to order from mouser.

[electromike]

Humm... I just put together all of the components and hooked it up to my car, However the unit doesn't go past the init screen. No message saying failed or success. My car is a 97 Civic, so i should just wire everything up according OBDuinoDiagram - opengauge - Google Code - Whole diagram of the Arduino board, LCD, ISO interface right?

There was nothing in the R110 version of the code I should have changed or anything? was there?

Thanks!

[Magister]

I was never able to test the ISO interface, but RussEnterprises had it almost working, I made some mod to the code for him, I checked them in R112, please try it.