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[on:]

Hi everyone,

I'm working on a senior design project at school and I have some questions I'm hoping some of you can help out with.
First off, we're trying to make an android application that reads from a vehicles OBD-II port, but also has the ability to start the car, lock/unlock doors, window control etc.
We want to use an ELM327 chip to read data from the OBD-II port, the ELM327 is basically a microcontroller that is pre-programmed to request and receive data from a car.  We are trying to interface the Arduino BT board with this ELM chip so that the Arduino can receive signals from the phone and then either start the car or pass these messages on to the ELM to read data from the car.  So that the ELM and Arduino should be interfaced using the Tx and Rx pins, but we wanted to know:
1) how we can go about getting a PCB made with these specific parts that we want (a pre-programmed ELM327 and an Arduino BT board + MCU), given that we have EAGLE files for the Arduino board?
2) Once a PCB is made, will we still be able to program the MCU on the Arduino?

I hope these questions make sense and sorry if the answers are obvious, I don't have a whole lot of experience with embedded design.
Thank you for your help!

[Reply #1 on:]

we're trying to make an android application that reads from a vehicles OBD-II port, but also has the ability to start the car, lock/unlock doors, window control etc.

Sounds like a illegal action in most countries.

If I understand correctly you want to make the following pipeline:

Android BT <---> BT Arduino < --> ELM327 <--> ODB-II    

You could just connect - http://www.sparkfun.com/products/9555 - with the Arduino using NewSoftSerial - http://arduiniana.org/libraries/newsoftserial/ - remember that TX connects to RX and you need a common ground. I would certainly not make a separate PCB for that.

You have to search the forum for bluetooth Android side, no experience with that one. Keep us informed of your progress.

[Reply #2 on:]

Say me what is your license plate, hacking BT is a 2 min job, then I can slam your brakes your you are driving around or blow up your airbags.
Cars are not toys....

[Reply #3 on:]

I can slam your brakes your you are driving around or blow up your airbags.

Please first blow up the airbags before hitting the brakes

[Reply #4 on:]

we're trying to make an android application that reads from a vehicles OBD-II port, but also has the ability to start the car, lock/unlock doors, window control etc.

Sounds like a illegal action in most countries.

If I understand correctly you want to make the following pipeline:

Android BT <---> BT Arduino < --> ELM327 <--> ODB-II    

You could just connect - http://www.sparkfun.com/products/9555 - with the Arduino using NewSoftSerial - http://arduiniana.org/libraries/newsoftserial/ - remember that TX connects to RX and you need a common ground. I would certainly not make a separate PCB for that.

You have to search the forum for bluetooth Android side, no experience with that one. Keep us informed of your progress.

Thanks for the reply man.  As far being illegal, I'm thinking it's not because it basically does the same thing that the Buick and GM apps that you see commercials for.  Either way though, it's not, and never will be, a commercial product, its only a school project.  I totally agree with your comment that we normally wouldn't need a separate PCB; unfortunately though, our professor will not let us buy design boards and use them in the final version.  He wants all the hardware on one chip and wants us to get experience designing and making PCBs, even if we just make them straight from the EAGLE files.

[Reply #5 on:]

I'm thinking it's not because it basically does the same thing that the Buick and GM apps that you see commercials for.

It's OK, you're in the US; land of the free, home of the ambulance chaser.

Just carry on, enjoy.