Difference between revisions of "F15: Car Report"

Revision as of 07:04, 17 December 2015

Grading Criteria

Project Title

Car Project: OBD-II Design using CAN Protocol

Abstract

For our project, we will be building an OBD II device that will interface with a vehicle through CAN Bus protocol. OBD II stands for On-Board Diagnostic II, which is used to track and monitor a vehicle's status and functions. A DB-9 connector to OBD-II cable and SJ One Board were used to connect our device to the car in order to record real-time information of the vehicle like the temperature, engine check, and MPH. After gathering all required information, you can diagnose any faults in the vehicle that may appear.

Objectives & Introduction

A device like OBD-II was introduced to the automobile industry in the late 1970's and it is still widely used today as a diagnostic tool for a vehicle from engine control to parts records. OBD-II is used by mechanics, car owners, agencies, and car manufactures to ensure vehicle is within the EPA emission standards. As California has become one of the leading states for the car industry, we decided building an OBD-II will lead to a better understanding of CAN Bus interface that is widely used in the car industry.

To design a OBD-II, we used a voltage regulator, switching circuit, transceiver, OBD-II to DB-9 cable, DB-9 connector, and a micro controller on the SJ One board. We used CAN interface to transmit and receive information regarding the vehicle. The objective of an OBD-II is to establish strong and reliable connection to a vehicle in order to gather valid and real-time information like MPH, RPM, engine check, temperature, car performance, and any faults. The OBD-II to DB-9 cable is connected to the car and SJ One Board. A simple flowchart regarding the overview of how the system is connected is shown in Figure 1.

Figure 1. A simple Flowchart of the Overview System Connection.

Team Members & Responsibilities

• Yasmine Jamjoum
  • Hardware Design and Software Implementation of CAN Bus
• Khang Doan
  • Hardware Design and Software Implementation of CAN Bus

Schedule

Parts List & Cost

Hardware

• OBD-II to DB-9 Cable [$9.95]

• Prototype board [$12.99]

• DB-9 Male Connector, Switch, LED, resistor, LM7805 voltage regulator [$10.99]

• LCD Display [$34.99]

• Vehicle: 2004 Acura TL [$10,100]

Software

• Windows Vista/7 (32 or 64-bit)

• Eclipse IDE

Design & Implementation

The design section can go over your hardware and software design. Organize this section using sub-sections that go over your design and implementation.

Hardware Design

The ODB-II hardware design included a battery supply, voltage regulator, switch circuit, MCP 2551 transceiver, a DB-9 connector, and a OBD-II to DB-9 cable to connect the to the car. The OBD-II system can be found in cars manufactured in the year 1996 and later. The OBD-II connection to the car reveals the car's status such as temperature, MPH, and error faults. The CAN Bus pins from the DB-9 connector are connected to the Rx and Tx pins on the SJ One Board along with the voltages and common ground. The pin diagram of the DB-9 connector is shown as Figure 2. The switch circuit is used to enable and disable the whole system along with a red LED to alert the user the system is activated. A voltage regulator is used to stablize the voltage going through the circuit. The transceiver was used to transmit and receive from and to the CAN protocol. The purpose of the transceiver is to interface the CAN protocol and the actual physical bus. The transceiver allows a suitable signal to be transmitted over the CAN bus protocol. The pins of the transceiver are connected to the SJ One Board along with voltage and common ground. The pin diagram of the transceiver is shown as Figure 3.

Figure 2. Pin Diagram of the OBD-II and DB-9.

Figure 3. Pin Diagram of the MPC 2551 Transceiver.

Hardware Interface

In this section, you can describe how your hardware communicates, such as which BUSes used. You can discuss your driver implementation here, such that the Software Design section is isolated to talk about high level workings rather than inner working of your project.

To implement this project, we used CAN Bus Protocol with a CAN High and CAN low signals. The Rx and Tx pins on the SJ One Board are connected to the CAN H and CAN L pins from the DB-9 connector. The DB-9 connector will allow the connection of the OBD-II to DB-9 cable to the vehicle that will transmit and receive information regarding the vehicle's status and any faults occurring in the vehicle. In between the connection of the DB-9 connector and the SJ One Board, we have a MCP 2551 transceiver to allow the interface between the CAN protocol and the bus. The CAN H and CAN L pins from the transceiver are connected to the CAN H and CAN L of the DB-9 connector which are pins 7 and 2, respectively. The TxD and RxD pins of the transceiver and connected to the Rx and Tx of the SJ On Board which are pins P0.1 and P0.0, respectively. Pin VDD of the transceiver is connected to the Vcc from the SJ One Board and pin Vss of the transceiver is connected to common ground. The voltage regulator is connected to the Vcc of the DB-9 connector, common ground, and the switch circuit. The switch circuit is used to enable the whole system and the voltage regulator is used to stabilize the voltage levels.

Figure 4. Schematics of the Hardware Connection.

Software Design

Show your software design. For example, if you are designing an MP3 Player, show the tasks that you are using, and what they are doing at a high level. Do not show the details of the code. For example, do not show exact code, but you may show psuedocode and fragments of code. Keep in mind that you are showing DESIGN of your software, not the inner workings of it.

Implementation

This section includes implementation, but again, not the details, just the high level. For example, you can list the steps it takes to communicate over a sensor, or the steps needed to write a page of memory onto SPI Flash. You can include sub-sections for each of your component implementation.

Testing & Technical Challenges

Describe the challenges of your project. What advise would you give yourself or someone else if your project can be started from scratch again? Make a smooth transition to testing section and described what it took to test your project.

Include sub-sections that list out a problem and solution, such as:

My Issue #1

Discuss the issue and resolution.

Conclusion

Conclude your project here. You can recap your testing and problems. You should address the "so what" part here to indicate what you ultimately learnt from this project. How has this project increased your knowledge?

Project Video

Upload a video of your project and post the link here.

Project Source Code

• Sourceforge Source Code Link

References

Acknowledgement

We would like to thank the following people for their contributions during this project:

Preet Kang

References Used

Introduction to CAN Hacking

http://hackaday.com/2013/10/21/can-hacking-introductions/

Introduction to CAN Protocols

http://hackaday.com/2013/10/29/can-hacking-protocols/

Hacking into Vehicle

http://fabiobaltieri.com/2013/07/23/hacking-into-a-vehicle-can-bus-toyothack-and-socketcan/

Appendix

OBD-II to DB9 Cable

https://www.sparkfun.com/products/10087

LPC1759 Datasheet

http://www.nxp.com/documents/data_sheet/LPC1759_58_56_54_52_51.pdf

LPC176x/5x User manual

http://www.nxp.com/documents/user_manual/UM10360.pdf

MCP 2551 Transceiver

http://www.electroschematics.com/wp-content/uploads/2015/07/MCP2551-datasheet.pdf