All of the technological improvements to vehicles over the past few decades have led to cars and trucks that would seem borderline magical to anyone driving something like a Ford Pinto in the 1970s. Not only are cars much safer due to things like crumple zones, anti-lock brakes, air bags, and compulsory seat belt use, but there’s a wide array of sensors, user interfaces, and computers that also improve the driving experience. At least, until it starts wearing out. The electronic technology in our modern cars can be tricky to replace, but [Aravind] at least was able to replace part of the instrument cluster on his aging (yet still modern) Skoda and improve upon it in the process.

These cars have a recurring problem with the central part of the cluster that includes an LCD display. If replacement parts can even be found, they tend to cost a significant fraction of the value of the car, making them uneconomical for most. [Aravind] found that a 3.5″ color LCD that was already available fit perfectly in the space once the old screen was removed, so from there the next steps were to interface it to the car. These have a CAN bus separated from the main control CAN bus, and the port was easily accessible, so an Arduino with a RTC was obtained to handle the heavy lifting of interfacing with it.

Now, [Aravind] has a new LCD screen in the console that’s fully programmable and potentially longer-lasting than the factory LCD was. There’s also full documentation of the process on the project page as well, for anyone else with a Volkswagen-adjacent car from this era. Either way, it’s a much more economical approach to replacing the module than shelling out the enormous cost of OEM replacement parts. Of course, CAN bus hacks like these are often gateway projects to doing more involved CAN bus projects like turning an entire vehicle into a video game controller.

Whilst swapping out the stereo in his car for a more modern Android based solution, [Aaron] noticed that it only utilised a single CAN differential pair to communicate with the car as opposed to a whole bundle of wires employing analogue signalling. This is no surprise, as modern cars invariably use the CAN bus to establish communication between various peripherals and sensors.

In a series of videos, [Aaron] details how he used this opportunity to explore some of the nitty-gritty of CAN communication. In Part 1 he designs a cheap, custom CAN bus sniffer using an Arduino, a MCP2515 CAN controller and a CAN bus driver IC, demonstrating how this relatively simple hardware arrangement could be used along with open source software to decode some real CAN bus traffic. Part 2 of his series revolves around duping his Android stereo into various operational modes by sending the correct CAN packets.

These videos are a great way to learn some of the basic considerations associated with the various abstraction layers typically attributed to CAN. Once you’ve covered these, you can do some pretty interesting stuff, such as these dubious devices pulling a man-in-the-middle attack on your odometer! In the meantime, we would love to see a Part 3 on CAN hardware message filtering and masks [Aaron]!

Here’s a classic “one thing led to another” car hack. [Alexandre Blin] wanted a reversing camera for his old Peugeot 207 and went down a rabbit hole which led him to do some extreme CAN bus reverse-engineering with Arduino and iOS. Buying an expensive bezel, a cheap HDMI display, an Arduino, a CAN bus shield, an iPod touch with a ghetto serial interface cable that didn’t work out, a HM-10 BLE module, an iPad 4S, the camera itself, and about a year and a half of working on it intermittently, he finally emerged poorer by about 275€, but victorious in a job well done. A company retrofit would not only have cost him a lot more, but would have deprived him of everything that he learned along the way.

Adding the camera was the easiest part of the exercise when he found an after-market version specifically meant for his 207 model. The original non-graphical display had to make room for a new HDMI display and a fresh bezel, which cost him much more than the display. Besides displaying the camera image when reversing, the new display also needed to show all of the other entertainment system information. This couldn’t be obtained from the OBD-II port but the CAN bus looked promising, although he couldn’t find any details for his model initially. But with over 2.5 million of the 207’s on the road, it wasn’t long before [Alexandre] hit jackpot in a French University student project who used a 207 to study the CAN bus. The 207’s CAN bus system was sub-divided in to three separate buses and the “comfort” bus provided all the data he needed. To decode the CAN frames, he used an Arduino, a CAN bus shield and a python script to visualize the data, checking to see which frames changed when he performed certain functions — such as changing volume or putting the gear in reverse, for example.

The Arduino could not drive the HDMI display directly, so he needed additional hardware to complete his hack. While a Raspberry Pi would have been ideal, [Alexandre] is an iOS developer so he naturally gravitated towards the Apple ecosystem. He connected an old iPod to the Arduino via a serial connection from the Dock port on the iPod. But using the Apple HDMI adapter to connect to the display broke the serial connection, so he had to put his thinking cap back on. This time, he used a HM-10 BLE module connected to the Arduino, and replaced the older iPod Touch (which didn’t support BLE) with a more modern iPhone 4S. Once he had all the bits and pieces working, it wasn’t too long before he could wrap up this long drawn upgrade, but the final result looks as good as a factory original. Check out the video after the break.

It’s great to read about these kinds of hacks where the hacker digs in his feet and doesn’t give up until it’s done and dusted. And thanks to his detailed post, and all the code shared on his GitHub repository, it should be easy to replicate this the second time around, for those looking to upgrade their old 207. And if you’re looking for inspiration, check out this great Homemade Subaru Head Unit Upgrade.

The CAN bus has become a defacto standard in modern cars. Just about everything electronic in a car these days talks over this bus, which makes it fertile ground for aspiring hackers. [Daniel Velazquez] is striking out in this area, attempting to decode the messages on the CAN bus of his Smart ForTwo.

[Daniel] has had some pitfalls – first attempts with a Beaglebone Black were somewhat successful in reading messages, but led to strange activity of the car and indicators. This is par for the course in any hack that wires into an existing system – there’s a high chance of disrupting what’s going on leading to unintended consequences.

Further work using an Arduino with the MCP_CAN library netted [Daniel] better results, but  it would be great to understand precisely why the BeagleBone was causing a disturbance to the bus. Safety is highly important when you’re hacking on a speeding one-ton metal death cart, so it pays to double and triple check everything you’re doing.

Thus far, [Daniel] is part way through documenting the messages on the bus, finding registers that cover the ignition and turn signals, among others. Share your CAN hacking tips in the comments. For those interested in more on the CAN bus, check out [Eric]’s great primer on CAN hacking – and keep those car hacking projects flowing to the tip line!

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.

While driving around one day, [Esko] noticed that the numbers and dials on a speedometer would be a pretty great medium for a clock build. This was his first project using a microcontroller, and with no time to lose he got his hands on the instrument cluster from a Fiat and used it to make a very unique timepiece.

The instrument cluster he chose was from a diesel Fiat Stilo, which [Esko] chose because the tachometer on the diesel version suited his timekeeping needs almost exactly. The speedometer measures almost all the way to 240 kph which works well for a 24-hour clock too. With the major part sourced, he found an Arduino clone and hit the road (figuratively speaking). A major focus of this project was getting the CAN bus signals sorted out. It helped that the Arduino clone he found had this functionality built-in (and ended up being cheaper than a real Arduino and shield) but he still had quite a bit of difficulty figuring out all of the signals.

In the end he got everything working, using a built-in servo motor in the cluster to make a “ticking” sound for seconds, and using the fuel gauge to keep track of the minutes. [Esko] also donated it to a local car museum when he finished so that others can enjoy this unique timepiece. Be sure to check out the video below to see this clock in action, and if you’re looking for other uses for instrument clusters that you might have lying around, be sure to check out this cluster used for video games.

The mechanics in dashboards are awesome, and produced at scale. That’s why our own [Adam Fabio] is able to get a hold of that type of hardware for his Analog Gauge Stepper kit. He simply adds a 3D printed needle, and a PCB to make interfacing easy.