A LIN Bus Signal Injector

LIN bus signal injector

[Zapta] tipped us about his latest project: a LIN bus signal injector. For our unfamiliar readers, the LIN bus is a popular automotive bus that is used to interface with buttons, lights, etc. As [Zapta] was tired of having to press the Sport Mode button of his car each time he turned the ignition on, he thought it’d build the platform shown above to automatically simulate the button press.

The project is based around an ATMega328 and is therefore Arduino IDE compatible (recognized as an Arduino Mini Pro), making firmware customization easy. In the car, it is physically setup as a proxy between the LIN master and the slave (which explains the two 3-wires groups shown in the picture). It is interesting to note that the injection feature can be toggled by using a particular car buttons press sequence. The project is fully open source and a video of the system in action is embedded after the break.

8 thoughts on “A LIN Bus Signal Injector

  1. The whole reason behind that the car doesn’t remember the last state set for the “sports” mode is because of environmental concerns.

    Automaker can simply sell a sporty car that defaults to economy mode, and then it will be classified as a economic car even if the owners themselves press the “sports” button right after ignition.

    So it is simply good old fashioned rule bending.

    1. In the Honda I drive I would use this device to set the ‘ECON’ mode each time the car starts. If I ever get around replacing the Japanese nav system with a tablet or similar, perhaps this unit could also be used to interface to the +13 buttons on the steering wheel. Nice work!

    2. not just environment, it’s also more dangerous to drive … some cars lock the rear dif, stiffen the suspicion, tighten the steering, and disable safety features …. sports mode is a button for a reason … somthing you use just on the track or when someone starts matching speeds with you on an empty highway …

  2. Awesome project. I bet this would be a huge marketable product. Think of when these cars are 10-20 years old and peoples children get a hold of them. These are the kind of hacks that will be installed in “old” cars of the future.

    I love this stuff.

  3. On old Toyotas the hack is simple. Replace the momentary “PWR” switch with a locking one and the job is done. Older models had locking switches and the ECU still recognizes this on newer ones.

  4. OMG he had to turn the ignition AND push a button – that was dreadful.

    Luckily kids today have microcontrollers to do such tedious tasks for them.

    Snark aside, nice build.

    1. You can usually turn that off. I rented a Saab once that did that. Second day I had it I checked the manual and there was way to disable it.

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