(Image: Header Graphic)

Tuesday, January 28, 2020

Doug's Domain

Doug Vetter, ATP/CFI

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E36 BMW OBC Project

(Image: DVOBC 3D Profile View)
Inspired by the OpenOBC Project I've decided to fund an R&D
project to replace the main logic board in the 18 button OBC
provided as an option on E36 BMW automobiles built from 1992-1998.

The DVOBC project picks up where the OpenOBC project left off, and aims to provide a replacement for the main logic board in the factory 18 button OBC of E36 BMWs (1992-1999).

Project Goals

(Image: Solidworks render of top of X1071 connector)

  1. Provide functionality equivalent to the factory 18 button OBC logic board.

  2. Create a modular architecture that allows the design to be flexible and expandable over time to support everything from diagnostics to data acquisition.

Product Variants

  1. A fully assembled logic board option to satisfy a niche market need for this board to replace the factory 18 button OBC logic board.

    Availablility: This product variant will be produced if a sufficient number of pre-orders occur.

  2. A turn-key product that will utilize the same logic board as in the first variant, mated to a daughtercard unique to this variant that will host a sunlight readable, high resolution color TFT display with capacitive touchscreen interface, all housed in a custom case that will replace the factory OBC in its entirety.

    Availability: This product variant is not currently slated for production but may be approved at a later date based on a variety of factors, including the success of the assembled logic board variant.

Hardware Features

Developer Information

The hardware design will remain proprietary to prevent unauthorized duplication, at least until I achieve a return on my considerable investment in the project. However, specifications and documentation will be provided to registered developers as required to facilitate expansion module hardware development and related software development.

Access to a software load supporting the assembled logic board product variant will be provided via an open source model, but support for this software will be limited to registered developers.

More information about the developer program will be released when appropriate.


(Image: Solidworks render of top of X1071 connector)

  1. Will your project provide backward compatibility with the OpenOBC project board? In other words, if I have already wired up stuff to the OpenOBC, will I be able to simply swap the OpenOBC board with your board?

    Simple answer: No. My design is completely different. However, I see my project not only meeting the original design goal of the OpenOBC project, which was to replace the functionality of the factory OBC logic board, but also providing additional functionality through the expansion module interfaces, so it's likely that whatever functionality you are utilizing could be provided via an expansion module.

  2. Why did you not simply take the OpenOBC gerbers and produce PCBs from that existing design?

    Several components were no longer available, and replacements were not pin-compatible, hence the PCB footprints had to change. That dictated a re-spin of the PCB.

  3. Why did you not simply copy the basic design of the OpenOBC and generate a new board with new footprints for the obsoleted components?

    First, my technical analysis of the OpenOBC project revealed several deviations from what I consider acceptable design practices so my design aims to correct these deviations. Second, I needed to improve the modularity and functionality of the board to expand the target market for the design as required to improve my return on investment, not only in terms of monetary value but the technology I develop for this board that I can leverage in future designs, thus reducing development costs on those projects. Finally, I did not want to imply any compatibility with or support for the OpenOBC boards that may be in the field.

  4. Do you plan to sell bare PCBs that can be assembled by the end user?

    No, primarily because the complexity of the design and the space constraints dictated by the dimensions of the original factory OBC logic board have required the use of some package types that are challenging to reliably assemble.

    This option would also necessitate revealing the bill of materials and put my IP at risk.

  5. Why are you producing the LCD option?

    While market research has clearly indicated a demand for the assembled logic board variant, I believe the market for a turn-key solution is far larger and so the overall success of the product is more dependent on that option. As a result, I expect to develop a prototype that demonstrates the basic functionality of both variants before the logic board option is manufactured to ensure the same logic board can be used for both variants.

  6. How can I buy or reserve one?

    Once the prototype is complete my intention is to announce a preorder program for the boards that will remain open for a limited period of time, similar in concept to a Kickstarter campaign. If I obtain sufficient sales within that timeframe I will proceed with manufacturing and notify you of an estimated shipping date. If insufficient orders are realized I will abandon manufacturing efforts and refund the purchase price.

Project Status (8/2019): ACTIVE

Baseboard schematics and initial component placement are complete. Development of the SM schematics is currently underway. Development of the LCD daughtercard is next. Once all boards have been integrated mechanically and electrically, routing will begin.

Questions / Comments

If you have any questions or comments about this project please contact me. However, please do not bother asking "when will this project be done". This project is receiving due attention but I must still work on it in my spare time. With limited spare time available I cannot commit to any timeframe for completion.