Open source OBD-II Adapter

Automotive diagnostics have come a long way since the “idiot lights” of the 1980s. The current version of the on-board diagnostics (OBD) protocol provides real time data as well as fault diagnostics, thanks to the numerous sensors connected to the data network in the modern vehicle. While the hardware interface is fairly standardized now, manufacturers use one of several different standards to encode the data. [Alex Sidorenko] has built an open source OBD-II Adapter which provides a serial interface using the ELM327 command set and supports all OBD-II standards.

The hardware is built around the LPC1517 Cortex-M3 microprocessor and can accept a couple of different versions. Here’s the PDF schematic, and a set of Gerber files (ZIP archive) for the PCB layout, if you’d like to dig in to it’s internals. The MC33660 ISO K Line Serial Link Interface device is used to provide bi-directional half-duplex communication interface with the micro-controller. Also included is the TJF1051, a high-speed CAN transceiver that provides an interface between the micro controller and the physical two-wire CAN lines on the ODB-II connector. The serial output from the adapter board is connected to a computer using a serial to USB adapter.

The software is written in C++ for the LPCXpresso IDE – a GNU tool chain for ARM Cortex-M processors, but can also be compiled using a couple of other toolchains. He’s got instructions if you’d like to build the firmware from source, or if you’d like to program the adapter via Flash Magic.

We featured [Alex]’s inexpensive PIC based ODB-II interface way back in 2007, so he’s been working on this for a while and has a good grip on what he’s doing.

Speaking CAN With Open Source Hardware

You can buy a dongle with a weird industrial connector that fits under the dash of any car on the road for $15. This is just a simple ODB-II transceiver meant for reading error codes and turning a Crown Vic into a police interceptor. There’s a lot more to the CAN Bus than OBD-II; robots and industrial control units, for instance, and Hackaday alum [Eric] has developed an open source tool for all things CAN.

[Eric] built this tool because of a lac of open-source tools that can talk CAN. There are plenty of boards floating around that can reset codes in a car using OBD-II, but an open hardware CAN device doesn’t really exist.

The CANtact is a small board outfitted with a USB port on one end, a DE-9 port on the other, and enough electronics to talk to any CAN device. The hardware on the CANtact is an STM32F0 – an ARM Cortex M0 that comes with USB and CAN interfaces. This chip connects to a Microchip CAN transceiver, and that’s pretty much all you need to talk to cars and industrial automation equipment. If doing something legal, moral, or safe with the CAN bus in your car isn’t your thing, Wired reports you can digitally cut someone’s brake lines.

On the software side of things, the CANtact can interface with Wireshark and the CANard Python library. All the files, from hardware to software, are available on the Github. Oh, CANtact was at Black Hat Asia, which means [Eric] was at Black Hat Asia. We should have sent stickers with him.

Control everything in your car with the Car Kracker

If your whip is a Honda, Toyota, BMW, Chrysler, VW, or Mini made in the last decade or so, the Car Kracker is for you. This project allows you to connect directly to your car’s computer system, allowing you to display messages on your stereo, play music off an SD card, and even override factory settings like always-on daytime running lights.

The Car Kracker uses ISO 9141, an in-car communications protocol that is now mostly used in foreign (for the US) cars. The build uses a Gadget Gangster Propeller board to connect to the CD changer port and OBD-2 port in the trunk, and the diagnostic port located under the hood.

With the Car Kracker, it’s easy to connect the Aux In on your stereo to an SD card loaded with music, or even plug in an iPod for the poor souls without a 1/8″ jack. Dealer customizations such as turning the ‘door is ajar’ noise off, toggling daytime running lights, and throwing a nav warning up are also possible.

Check out the two videos after the break, and if anyone has any more info on getting this deep into a car’s computer system (a wiki, maybe?), send a link in on the tip line.

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