vehicle

47 Articles

Custom Packet Sniffer Is A Great Way To Learn CAN

July 2, 2020 by 18 Comments

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]!

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Inside A CAN Bus Mileage Manipulator

March 13, 2020 by 28 Comments

In the days of carburetors and leaf spring suspensions, odometer fraud was pretty simple to do just by disconnecting the cable or even winding the odometer backwards. With the OBD standard and the prevalence of electronics in cars, promises were made by marketing teams that this risk had all but been eliminated. In reality, however, the manipulation of CAN bus makes odometer fraud just as easy, and [Andras] is here to show us exactly how easy with a teardown of a few cheap CAN bus adapters.

We featured another project that was a hardware teardown of one of these devices, but [Andras] takes this a step further by probing into the code running on the microcontroller. One would imagine that basic measures would have been taken by the attackers to obscure code or at least disable debugging modes, but on this one no such effort was made. [Andras] was able to dump the firmware from both of his test devices and start analyzing them.

Analyzing the codes showed identical firmware running on both devices, which made his job half as hard. It looked like the code was executing a type of man-in-the-middle attack on the CAN bus which allowed it to insert the bogus mileage reading. There’s a lot of interesting information in [Andras]’s writeup though, so if you’re interested in CAN bus or attacks like this, it’s definitely worth a read.

Solar Panel Keeps Car Battery Topped Off Through OBD-II Port

March 10, 2020 by 47 Comments

Up until the 1980s or so, a mechanic could check for shorts in a car’s electrical system by looking for sparks while removing the battery terminal with everything turned off in the car. That stopped being possible when cars started getting always-on devices, and as [Kerry Wong] learned, these phantom loads can leave one stranded with a dead battery at the airport after returning from a long trip.

[Kerry]’s solution is simple: a solar trickle charger. Such devices are readily available commercially, of course, and generally consist of a small photovoltaic array that sits on the dashboard and a plug for the lighter socket. But as [Kerry] points out in the video below, most newer model cars no longer have lighter sockets that are wired to work without the ignition being on. So he chose to connect his solar panel directly to the OBD-II port, the spec for which calls for an always-on, fused circuit connected directly to the positive terminal of the vehicle battery. He had to hack together an adapter for the panel’s lighter plug, the insides of which are more than a little scary, and for good measure, he added a Schottky diode to prevent battery discharge through the panel. Even the weak winter sun provides 150 mA or so of trickle charge, and [Kerry] can rest assured his ride will be ready at the end of his trip.

We used to seeing [Kerry] tear down test gear and analyze unusual devices, along with the odd post mortem on nearly catastrophic failures. We’re glad nothing burst into flames with this one.

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Dashboard Dongle Teardown Reveals Hardware Needed To Bust Miles

December 16, 2019 by 43 Comments

Progress and the proliferation of computers in automotive applications have almost made the shade tree mechanic a relic of the past. Few people brave the engine compartment of any car made after 1999 or so, and fewer still dive into the space behind the dashboard. More’s the pity, because someone may be trying to turn back the odometer with one of these nefarious controller area network (CAN bus) dongles.

Sold through the usual outlets and marketed as “CAN bus filters,” [Big Clive] got a hold of one removed from a 2015 Mercedes E-Class sedan, where a mechanic had found it installed between the instrument cluster and the OEM wiring harness. When the dongle was removed, the odometer instantly added 40,000 kilometers to its total, betraying someone’s dishonesty.

[Big Clive]’s subsequent teardown of the unit showed that remarkably little is needed to spoof a CAN bus odometer. The board has little more than an STM32F microcontroller, a pair of CAN bus transceiver chips, and some support circuitry like voltage regulators. Attached to a wiring harness that passes through most of the lines from the instrument cluster unmolested while picking off the CAN bus lines, the device can trick the dashboard display into showing whatever number it wants. The really interesting bit would be the code, into which [Clive] does not delve. That’s a pity, but as he points out, it’s likely the designers set the lock bit on the microcontroller to cover their tracks. There’s no honor among thieves.

We found this plunge into the dark recesses of the automotive world fascinating, and [Big Clive]’s tutelage top-notch as always. If you need to get up to speed on CAN bus basics, check out [Eric Evenchick]’s series on automotive network hacking.

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Electric Dump Truck Produces More Energy Than It Uses

August 22, 2019 by 77 Comments

Electric vehicles are everywhere now. It’s more than just Leafs, Teslas, and a wide variety of electric bikes. It’s also trains, busses, and in this case, gigantic dump trucks. This truck in particular is being put to work at a mine in Switzerland, and as a consequence of having an electric drivetrain is actually able to produce more power than it consumes. (Google Translate from Portugese)

This isn’t some impossible perpetual motion machine, either. The dump truck drives up a mountain with no load, and carries double the weight back down the mountain after getting loaded up with lime and marl to deliver to a cement plant. Since electric vehicles can recover energy through regenerative braking, rather than wasting that energy as heat in a traditional braking system, the extra weight on the way down actually delivers more energy to the batteries than the truck used on the way up the mountain.

The article claims that this is the largest electric vehicle in the world at 110 tons, and although we were not able to find anything larger except the occasional electric train, this is still an impressive feat of engineering that shows that electric vehicles have a lot more utility than novelties or simple passenger vehicles.

Thanks to [Frisco] for the tip!

A Big, Mean, Inflated Machine

March 1, 2019 by 21 Comments

A Jeep is fun offroad, a motorcycle perhaps even more so. Diehard renegades go even further and get about in Unimogs and on snowmobiles. [amazingdiyprojects] might just have topped them all however, with his latest project – the astonishing Inflatable Car.

Despite the name, it’s a vehicle that defies clear definition. Consisting of a lightweight aluminium frame and exposed seat, the construction is almost 100% hacked. PVC fabric is used with advanced adhesive tapes to create inflatable wheels that are 2 meters in diameter. Vacuum cleaners are used to inflate the massive tyres, with custom 3D printed valves to ensure even inflation. Drive is courtesy of four handheld concrete mixers, repurposed for their torquey motors and robust geartrains. Even the user interface is a triumph of found parts – consisting of former cordless drills, used for their PWM hardware and covered in extra switches.

Looking like a moon lander from a strange 1950s version of the future, the machine is impressively nimble for its size. Episode 1 starts with a single wheel hooked up to the inflation gear and a single drive motor. Just a few short months later, episode 7 has the prototype machine crawling out from the confines of the back garden and out into the street. The machine is already impressively fast and capable, and we can’t wait to see what happens next.

It’s a build that is truly impressive in its scale, though we’ve come to expect no less from [amazingdiyprojects]. Video after the break.

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Predicting Weather With The Internet Of Cars

February 18, 2019 by 38 Comments

Follow this train of thought: cars have sensors, cars are in frequent use over large areas, cars are the ultimate distributed sensor network for weather conditions.

Many years ago, as I wasted yet another chunk of my life sitting in the linear parking lot that was my morning commute, I mused that there had to be a way to prevent this madness. I thought: What if there was a way for the cars to tell each other where slowdowns are? This was long before smartphones, so it would have to be done the hard way. I imagined that each vehicle could have a small GPS receiver and a wireless transceiver of some sort, to send the vehicle’s current position to a central server, which would then send the aggregate speed data for each road back to the subscriber’s car. A small display would show you the hotspots and allow you to choose an alternate route. Genius! I had finally found my billion dollar idea.

Sadly, it was not to be. Seemingly days later, everyone on the planet had a GPS-equipped smartphone in his or her pocket, and the complex system I imagined was now easily implemented as software. Comically, one of the reasons I chose not to pursue my idea is that I didn’t think anyone would willingly let a company have access to their location information. Little did I know.

So it was with great interest that I read an article claiming that windshield wiper data from connected cars can be used to prevent floods. I honestly thought it was a joke at first, like something from a Monty Python sketch. But as I read through the article, I thought about that long-ago idea I had had, which amounted to a distributed sensor platform, might actually be useful for more than just detecting traffic jams.

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