OBD-2 Input to the PIC

[oslinux]

Hi all!

I need to read some infos in a car, like the Fuel Level, Vehicle Speed, and other cool things, i need to input those in a PIC, there's an easy way to do this via OBD-2 in PIC BASIC Pro?

(The car is a FORD that use the PWM interface)

There's also another problem, i need some documents about the system that ford uses in OBD-2 via PWM, cause i've never worked with it, (But i've already studied PWM)

Could you help me, even only giving me some links about that?

Thank you!

Luca

[DynamoBen]

I've created several devices that use OBDII. The hard part is coding the communications protocol and designing the communications circuit from scratch. In addition you would need to purchase the SAE standard for OBDII to even get started.

That being said there is a simple way to communicate with your car. A company called Elm Electronics sells ICs that handle all the communications with the vehicle and spits out the results to your PC or in your case PIC in ASCII. This frees your PIC up to do what you want it to do and speeds development.

Go to http://www.elmelectronics.com/ and check out the ELM320 which is PWM or the ELM327 which is the all-in-one chip. I personally own every OBDII chip and love them, they work well.

[oslinux]

Ok, but they are simple pics from microchip, right?

so there's a way to code a software for a pic to do that,

anyway, with that chip i can use all of the function of OBD?

i can use the normal software for linux or windows that works with the serial obd?

thank you!

Luca

[DynamoBen]

Ok, but they are simple pics from microchip, right?
so there's a way to code a software for a pic to do that...

True they are just pics with code. You're welcome to spend the hundreds of dollars to buy the SAE standards, and then hours and hours creating code. I can say from personal expirence its a major task. I found that spending $14 on a device the handles all the communications was money well spent. Plus by changing Elm chips I can "talk" to different cars without rewriting my code.

with that chip i can use all of the function of OBD?

Depends what you mean. The product was designed to be an ODBII diagnostics tool. With the chip you will get all the normal engine data and diagnostic codes. The following site has some more information about the chip plus some free software and schematics. http://scantool.net/

i can use the normal software for linux or windows that works with the serial obd?

Not sure what you mean. If you're asking if you can tie your computer directly to the OBD buss the answer is no. There are currently 4 OBDII communications protocols all with very different communications methods but none are RS232 or TTL.

[oslinux]

True they are just pics with code. You're welcome to spend the hundreds of dollars to buy the SAE standards, and then hours and hours creating code. I can say from personal expirence its a major task. I found that spending $14 on a device the handles all the communications was money well spent. Plus by changing Elm chips I can "talk" to different cars without rewriting my code.

Ehhmmmmm... i guess you're right!

Depends what you mean. The product was designed to be an ODBII diagnostics tool. With the chip you will get all the normal engine data and diagnostic codes. The following site has some more information about the chip plus some free software and schematics. http://scantool.net/

Ok.

Not sure what you mean. If you're asking if you can tie your computer directly to the OBD buss the answer is no. There are currently 4 OBDII communications protocols all with very different communications methods but none are RS232 or TTL.

No, i meant "I can connect the serial output from the elm chip to a PC and then use a standard software for obd over serial to read the data?"

thank you for your help!

Luca

[DynamoBen]

No, i meant "I can connect the serial output from the elm chip to a PC and then use a standard software for obd over serial to read the data?"

Yes, the chip is designed to be used with something as simple as hyperterminal. No special software required.

[oslinux]

i've already buyed two ELM320, (One SMT and one TH),
but in the net i've found this:

http://www.sterntech.com/obdii_pic.php

it's an:
" Open source hand held OBDII code reader and scanner "

" PIC 18F8680 based open source code reader. "

there you can find the source, also.

maybe it's useful!