Shower Thoughts In Your Car

The subreddit for Shower Thoughts offers wisdom ranging from the profound to the mundane. For example: “Every time you cut a corner you make two more.” Apparently, [Harin] has a bit of an addiction to the subreddit. He’s been sniffing the CAN bus on his 2012 Hyundai Genesis and decided to display the top Shower Thought on his radio screen.

To manage the feat he used both a Raspberry Pi and an Arduino. Both devices had a MCP2515 to interface with two different CAN busses (one for the LCD display and the other for control messages which carries a lot of traffic.

The code is available on GitHub. There’s still work to do to make the message scroll, for example. [Harin] has other posts about sniffing the bus, like this one.

We’ve covered CAN bus quite a bit, including some non-automotive uses. We’ve even seen the CAN bus for model railroading.

11 thoughts on “Shower Thoughts In Your Car

  1. Just watch it with the MCP2515… I found that it’s very easy to get them vomiting up corrupt packets if you happen to send one just as an incoming packet is being received.

    I was able to reproduce the problem with a controller constantly sending a frame with the same pattern repeatedly to one CANbus ID whilst then sending a different pattern with the MCP2515 using a different ID. Every once in a while, the MCP2515 would send a frame with its own ID, but with the payload from the other controller.

    1. Haha. I knew someone would bring it up!
      I feel that this is bad news all around. Leave the car’s system alone, unless you want the brakes and airbag to activate when they shouldn’t. I hope I am wrong about this and that the systems are better protected than I imagine.

      1. There are two separate Canbus networks. One low speed, one high speed. They are not bridged, and the low speed one only controls and manages the radio in my car. Also the RPi is only connected to the LCD screen so what you’ve described is not currently possible.

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