Maintenance, Emissions, and Privacy: The OBD Story

The 90s were a pivotal time in world history, and 1996 was no different. You might have spent the year glued to the TV playing Super Mario 64, or perhaps you were busy campaigning for Bill Clinton or Bob Dole, or maybe you were so depressed that Princess Diana and Prince Charles divorced that you spent the whole year locked in your room, a prisoner of your own existential nihilism. Whatever you did, though, it’s likely that one major event passed you by without a thought: The standardization of on-board vehicle diagnostics (in the US), otherwise known as OBD-II.

In the 1970s, vehicles (in some western countries, at least) were subject to ever-increasing restrictions on emissions. Most companies began switching from carburetors to efficient fuel injection systems, but even that wouldn’t be enough for the new standards. Cars began to carry rudimentary computer systems to manage and control the influx of valves, meters, and sensors that became the new norm. And, as one would guess, every car company had their own standard for managing and monitoring these computer systems. Eventually they would settle on the OBD system that we have today.

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Smart Brake lights and more with OpenXC


At a recent hack-a-thon event, [Al Linke] tapped into a vehicle’s OBD port with an OpenXC vehicle interface and hacked an LED screen in the rear window to display data based on events. If you haven’t heard of OpenXC, you can expect to read more about it here at Hackaday in the near future. For now, all you need to know is that OpenXC is Ford’s open source API for real-time data from your vehicle: specifically 2010 and newer model Ford vehicles (for now).

[Al] connected the OpenXC interface to his Android phone over Bluetooth, transmitting data from the OBD port to the phone in real time. From here, the Android can do some really cool stuff. It can use text to speech to announce how much your lead foot cost you, add sound effects for different car events, and even interact with additional devices. Although he managed all of those features, [Al’s] primary goal was to add an LED screen that displayed messages on the vehicle’s back window.

When the phone detected a braking event from the car, it directed the LEDs to light up with a “braking” image, adding some flavor to the process of stopping. He could also change the image to a “Thank You” sign with a waving hand, or—for less courteous drivers—an “F U” image with a slightly different hand gesture. You’ll want to check your local and/or national laws before attempting to strap any additional lighting to your vehicle, but you can watch [Al’s] car light up in the video below. For a more detailed look under the hood, he’s also provided an Instructables page.  If OpenXC catches on, the number of vehicle hacks such as the Remote Controlled Car may skyrocket.

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Racing telemetry on a cockpit view


[Martin] has a Lotus Elise and access to a track. Sounds like fun, huh? The only problem is that the dashcam videos he makes are a little bit boring. Sure, they show him flying around the track, but without some sort of data it’s really hard to improve his driving skills. After thinking about it for a while, [Martin] decided he could use his Raspberry Pi and camera module to record videos from the dashboard of his car, and overlay engine data such as RPM, throttle, and speed right on top of the video.

Capturing video is the easy part of this build – [Martin] just connected his Raspi camera module and used the standard raspivid capture utility. Overlaying data on this captured video was a bit harder, though.

[Martin] had previously written about using the Raspi to read OBD-II data into his Raspi. Combine this with a Python script to write subtitles for his movies, and he’s off to the races, with a video and data replay of every move on the track.

The resulting movie and subtitle files can be reencoded to an HD movie. Reencoding a 13 minute HD video took 9 hours on the Raspi. We’d suggest doing this with a more powerful compy, but at least [Martin] has a great solution to fix his slightly uninformative track videos.