For Nissan 350z enthusiasts, the desire to personalize their ride often extends beyond aesthetics and performance modifications. Imagine integrating real-time vehicle data directly into your line of sight, enhancing both the driving experience and providing crucial information at a glance. This is the appeal of a heads up display (HUD). While aftermarket solutions exist, the pursuit of a truly custom and tailored system can be a rewarding endeavor. This article delves into the initial steps of creating a DIY OBD2 heads up display specifically for a 350z, leveraging the wealth of data available through the car’s onboard diagnostic system.
Understanding OBD2 and CAN Bus in Your 350z
Modern vehicles, including the Nissan 350z, are equipped with sophisticated onboard diagnostic systems, primarily accessed through the OBD2 (On-Board Diagnostics II) port. This standardized port, typically located under the driver’s side dashboard, was initially designed for emissions monitoring and diagnostic purposes. However, it has become a gateway to a vast amount of real-time vehicle data. Service technicians utilize this port to diagnose issues, but it also provides access for enthusiasts to tap into the inner workings of their car.
The OBD2 system communicates using various protocols, and importantly for more advanced data access, many modern cars, including the 350z, utilize a Controller Area Network (CAN) bus. CAN bus is a robust communication network that allows different electronic control units (ECUs) within the vehicle to communicate with each other. This network transmits a continuous stream of data related to engine parameters, sensor readings, and vehicle status. Critically, the CAN bus network is wired to the OBD2 port, typically on pins 6 and 14. This accessibility means that without invasive modifications, you can intercept and interpret the data flowing within your 350z’s CAN network. This “spying” on the CAN bus provides a fascinating look at how your car operates and offers the raw data needed for a custom HUD. Projects like the Knio Carhack project serve as excellent starting points and inspiration for those venturing into automotive CAN bus exploration.
Project Components: Hardware Essentials for OBD2 HUD Development
To embark on this DIY 350z Obd2 Heads Up Display project, specific hardware components are necessary to bridge the gap between your car’s OBD2 port and a computer for data processing and display. The core components chosen for this project include:
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CANUSB Module: A CANUSB module acts as the essential interface between the CAN bus network and a computer, typically a laptop in the development phase. This module translates the CAN bus signals into a format that a computer can understand via USB. It allows you to send and receive CAN messages, which is crucial for capturing the data from your 350z.
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OBD2-to-Serial Cable: To physically connect the CANUSB module to the 350z’s OBD2 port, an OBD2-to-serial cable is required. These cables typically feature a standard OBD2 connector on one end and a serial connector (DB9) on the other, designed for connecting to various diagnostic tools.
Connecting to Your 350z OBD2 Port and Cable Modification
Upon receiving the OBD2-to-serial cable, it was discovered that the factory wiring configuration was not directly compatible with the intended CANUSB setup. To rectify this, a modification of the cable was necessary. This involved carefully cutting the cable and resoldering specific wires to ensure correct CAN bus connectivity. The following wiring adjustments were made:
- CAN-L (CAN Low): Soldered to the brown wire from the serial cable side and the gray wire from the OBD2 connector side.
- Ground: Connected the purple wire from the serial cable side to the brown wire from the OBD2 connector side.
- CAN-H (CAN High): Joined the white wire from the serial cable side with the purple wire from the OBD2 connector side.
All other wires within the OBD2-to-serial cable were left disconnected to simplify the initial setup and focus solely on CAN bus communication.
Modified OBD2 cable showcasing custom wiring for Nissan 350z heads-up display project.
This modified cable now provides the correct physical and electrical connection to tap into the 350z’s CAN bus through the OBD2 port, allowing the CANUSB module to interface effectively.
Data Logging and Visualization: Unveiling 350z Data Streams
With the hardware connected and the CANUSB module in place, the next crucial step is to capture and interpret the data flowing through the 350z’s CAN bus. This involves creating software tools for both data logging and visualization.
A custom computer program was developed to communicate with the CANUSB module and record all incoming CAN messages. This logger program allows for filtering specific message IDs, which is essential for focusing on relevant data streams. The screenshot below illustrates the logger program in action, specifically filtering for messages with ID 180. The real-time CAN messages are displayed on the right side of the interface as they are received from the 350z.
Data logging software interface displaying real-time CAN bus messages from a Nissan 350z, part of a DIY heads-up display project.
Initial data logging revealed that the 350z CAN network utilizes approximately 30 distinct message IDs during normal vehicle operation. While this may seem like a limited number, each CAN message can contain up to 8 bytes of data, offering a wealth of information. These bytes can represent various parameters such as gas pedal position, vehicle speed (often spanning two bytes), and bitfields indicating the status of different vehicle systems and lights.
Decoding and understanding this raw CAN data is a significant challenge, as Nissan’s service manuals provide limited information on CAN bus specifics. To overcome this data interpretation hurdle, a separate data visualization program was created. This program processes the data logs generated by the logger program and presents it in a graphical format, making it easier to identify patterns and understand the meaning of different data points.
Data visualization software showing decoded CAN bus data from a Nissan 350z, displaying parameters like speed, RPM, and pedal positions for a custom heads-up display project.
The visualization tool displays various parameters over time. In the example screenshot:
- Top Graph: Represents vehicle speed.
- Top-Middle Graph: Shows engine RPM and gas pedal position.
- Bottom-Middle Graph: Large spikes indicate brake light status.
- Bottom Graph: Small spikes represent clutch pedal status.
This visual representation, even without advanced filtering or calculations applied, dramatically simplifies the process of analyzing and comparing logged data, paving the way for decoding specific data signals relevant for a heads up display.
Next Steps and Future Development
The project is currently in the data acquisition and decoding phase. The immediate next step is to integrate the ability to read standard OBD2 PID (Parameter IDs) information alongside the captured CAN bus data. This will allow for cross-referencing known OBD2 parameters with the raw CAN data, aiding in the identification and decoding of unknown CAN message data points. Progress on decoding the 350z CAN bus messages is being documented in this spreadsheet, which provides a continuously updated view of decoded parameters.
The ultimate goal remains to create a fully functional custom heads up display for the 350z. Future development will focus on:
- Complete CAN Bus Data Decoding: Continuing to analyze and decode the remaining CAN messages to access a wider range of vehicle parameters.
- HUD Software Development: Designing and developing software to process the decoded data and display it in a user-friendly HUD format.
- Hardware Integration: Selecting and integrating a suitable display for the heads up display, considering factors like brightness, clarity, and mounting options within the 350z cabin.
This project represents the initial steps in a journey to create a personalized and informative heads up display for the Nissan 350z, leveraging the power of OBD2 and CAN bus data to enhance the driving experience.
