OBDuino working with ELM327

[Magister]

Originally Posted by tom43571

electromike,

I will go ahead and order it then, possibly two in case I screw something up. My only other worry is the interface for the chip. It looks much more difficult to build than the one for iso and with my extremely limited electronics knowledge, it should prove to be a serious challenge.

ELM provides schematic, PCB design and even the gerber files for their interface, you could use them to help you build the interface

ELM Electronics - Chip Help

take a look at the "Where can I buy a circuit board for my ELM IC" paragraph

[marceloherman]

well,

I finally bought the duino. now, i need to build everything.

so, i was reading the tutorial code.google.com/p/opengauge/wiki/OBDuinoDiagram and there is nothing about my car's protocol.

my car is a 2000 year Ford with SAE J1850 PWM protocol. on that tutorial i saw ISO and CAN protocols.

I have an ELM327 interface working on my computer, but, how i need to plug the led display on the freeduino?

i bought this nkcelectronics.com/freeduino-serial-v20-board-kit-arduino-diecimila-compatib20.html and this nkcelectronics.com/16x2-lcd-module-while-characters-blue-backli162.html

thanks a lot by the help....

[Magister]

Your ELM327 interface is a closed enclosure? if it's the case you have to put a "NULL modem", a cable with TX/RX crossed, between your ELM interface and the freeduino. For the LCD there is a diagram on the wiki of the project
OBDuinoDiagram - opengauge - Whole diagram of the Arduino board, LCD, interface - Project Hosting on Google Code

[marceloherman]

i assembled my elm327.

i dont understand yet. here code.google.com/p/opengauge/wiki/OBDuinoInterface there is the interface with elm327 but the PWM protocol dont is used.

the pins 3, 4, 11 e 13 of the elm327 chip are not used on the diagram above. i must to buy the MC33290 chip too? the PWM will be converted on CAN protocol?

i am lost

but, again, thanks a lot by you help.

[Magister]

I assumed you have a full ELM327 interface, bought from eBay for instance? If this is the case then everything is inside to support all the protocol.
If not you have to built around your protocol with the various components needed, transistors, etc
A quick google find this:
http://images.forum-auto.com/mesimag...ns%20titre.jpg

[marceloherman]

yeap. I bought the ELM327 chip and assembled to all protocols. and it is working ok, but only on my computer. I think that is just plug the serial port of the ELM scan to serial port of the arduino. i think that is ok.

my problem is to put the LCD display on the arduino. how i need to connect the wires? which ports? on which pins? i need to buy the MC33290 chip? i just use this image opengauge.org/%7Eobduino/diagram/obduino.gif?

[Magister]

Yup I think it's the right diagram.

In the code it says :
#define DIPin 4 // register select RS
#define DB4Pin 7
#define DB5Pin 8
#define DB6Pin 12
#define DB7Pin 13
#define ContrastPin 6
#define EnablePin 5
#define BrightnessPin 9

it seems ok to me

[marceloherman]

i found what i wanted.

Arduino - LiquidCrystal

let me talk what i think about connect the arduino with my car and you can say if there is right or not.

I have the elm327 working. I will to assemble my arduino kit with LCD 8x2 like the schematic on the link above. After this, I will write a program in C/C++ to connect the arduino's serial port to elm327 serial port and read rpm, speed and so on.

Its right or I am entire crazy now? hhahahhaha....

thanks for you patience

[Magister]

This is what the OBDuino is doing, just connect your LCD as the diagram, and load the sketch in the Arduino IDE, compile, upload

obduino32K.pde - opengauge - Project Hosting on Google Code

uncomment the define ELM and comment the define ISO before compiling.

Also I don't remember if you need a crossed cable between the serial port of the Arduino and the ELM327 interface or a straight one!

[marceloherman]

hum......ok.....the code seams to be all that I need....great heheh..

i will assemble the lcd and arduino on this weekend. maybe i need some help ahead.

thanks a lot.