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.

23 thoughts on “Smart Brake Lights And More With OpenXC

    1. Most of it is definitely a distraction; but I would love if vehicles had a “deceleration meter” in the brake lights. It would make it so much easier to tell if the person 200 feet ahead is feathering their brakes, or slamming on them. Would also be useful for the same reason in bumper to bumper traffic.

      1. what a deceleration meter wouldn’t tell you is how fast you are going.
        people take that into account themselves when they judge how fast they are approaching a car.
        it could possibly even make tailback traffic worse as people over-anticipate.

      2. Some cars already feature this. Or at least were going to feature this. The only place I’ve actually seen it was on some massive trucks. Basically the breaklights would flash at a rate proportional to how hard you put your foot down. Feather the break and the breaklights would come on. Flash the breaks and they would blink in a seizure inducing fury.

        This is actually useful in multiple ways since we are terrible bags of water for judging a stationary visual queue. Humans fair very well with changing scene i.e. blinking lights.

  1. There’s a good reason why this is illegal in some places and should be illegal in all places: If someone is distracted by your sign and then proceeds to hit something, you are gonna be in some deep doo doo. The novelty factor alone is enough to pull eyes away from the road.

  2. And is completely useless in the daytime. his display is barely readable inside, in the back window it will be invisible to the driver behind.

    and honestly, that is a good thing. There is a reason many states have laws against these things and scrolling text ,etc…

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