Hey guys,

where can I tap the tire to get the reading for how fast I am currently moving in a no nav car?

Thanks,

Mike

 

Each wheel has its own speed sensor that sends pulses to the ECM. The ECM calculates the speed of the car by timing the pulses. It may be easier for you to get the vehicle speed using CAN bus or OBD-II.

 

I am a complete noob to this, where can I can find the OBD-II port? And what program do I need to run it?

I am thinking about using my car for an engineering project, if it does come down to it I will need to tap into my car for all the sensory information and sync it with our custom user interface.

 

Click on the link in my sig about the custom piggy-back. I tapped into the CAN bus, and spent TONS of time and effort decoding the data stream so that I could monitor the parameters I needed.

 

BTW, if you can share anything about your project, I'd really like to hear about it. If you are doing anything for commercial or retail use, then CAN bus is definitely the way to go. All cars built on or after '08 are required to support it. Cars built after '96 are required to support an inferior standard called OBD-II. There are many devices available that will allow you to interface it.

This is one of the ways that I can connect my laptop to the CAN bus in my car so that I can run my custom software. The other way is to connect my laptop to the microcontroller that is hard wired into my car, which has a built in CAN interface.

 

Hi I've actually looked at your thread ever since the beginning. I was curious then but your thread never said where the port/bus locations are within the vehicle itself. A quick look through the owner's manual in the fuse box section didn't yield any results either. Sorry if that was a really noob question.

When you connect to the CAN bus or OBD-II port, the data just comes into the USB port? If I open the port up it will just show jibberish right? So unless I know a way to decode the mess I can't really use it for anything, or are there software/interface that allows me to make sense of things.

Our project (currently underway) is to use RFID to transmit sign data to the car, and allows the car to warn driver of speed limits, road conditions, POI etc before the driver can see the signs, or if the signs are faded and obstructed. The tags will sent a signal to the reader mounted within the car, and the reader will transmit the signal data to the computer running a Visual Basic U.I, queries the database for a match and attributes, then will take the appropriate actions via a simple HUD device and through the car's speakers. I want to tap the car's speed info because I want it to warn driver if they are speeding as well.

Right now its just a demonstration, depends on the final result and if Rutgers wants to sponsor it further we might take it to the next level and sync it with the car completely and with a working SATNAV too.

 

Actually I've found some good information here:

http://www.thinkythings.org/obdii/

I just need to contact those software companies and see how easy it is to export the selected data I want real time out to maybe a spreadsheet or in VB itself

Lastly, our IS supports both OBD and CAN bus? Is the CAN bus located in a different place?

 

I'll read this again tomorrow when I'm sober, but I think you are on the right track. The OBD-II port in our car also has pins for the CAN bus. I think it is just under the steering wheel about half way to the brake pedal. However, there is also a termination block by the feet of the passenger's (and I think also the driver's) feet in front of the doors. That is where I connected my microcontroller.

There are MANY different "dongles" available from different vendors for ~$200 that include software to display, analyze, and datalog the various parameters.