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Fail of the Week: Subscription EV Charger Becomes Standalone, Briefly

1 Noviembre 2024 at 11:00

At this point in the tech dystopia cycle, it’s no surprise that the initial purchase price of a piece of technology is likely not the last payment you’ll make. Almost everything these days needs an ongoing subscription to do whatever you paid for it to do in the first place. It’s ridiculous, especially when all you want to do is charge your electric motorcycle with electricity you already pay for; why in the world would you need a subscription for that?

That was [Maarten]’s question when he picked up a used EVBox wall mount charger, which refused to charge his bike without signing up for a subscription. True, the subscription gave access to all kinds of gee-whiz features, none of which were necessary for the job of topping off the bike’s battery. A teardown revealed a well-built device with separate modules for mains supply and battery charging, plus a communications module with a cellular modem, obviously the bit that’s phoning home and keeping the charger from working without the subscription.

After some time going down dead ends and a futile search for documentation, [Maarten] decided to snoop into the conversation between the charger boards and the comms board, reasonably assuming that if he knew what they were talking about, he’d be able to mimic the commands that make the charger go. He managed to do exactly that, reverse engineering enough of the protocol to do a simple replay attack using a Raspberry Pi. That let him use the charger. Problem solved, right?

Not so fast — this is a “Fail of the Week,” after all. This is where [Maarten] should have called it a day, but he decided to keep poking enough to snatch defeat from the jaws of victory. He discovered that the charging module’s firmware was only doing limited validation of messages coming from the comms module, and since he’d only found fourteen of the commands in the protocol, he thought he’d take advantage of the firmware’s openness to explore all 256 possible commands. Scanning through all the commands proved fatal to the charger, though, bricking the poor thing right after he’d figured everything out. Ouch!

To his credit, [Maarten] was only trying to be complete in his exploration of the protocol, and his intention to make it easier for the next hacker is laudable in the extreme. That he took it a byte too far is unfortunate, but such is the price we sometimes pay for progress. Everything he did is thoroughly documented, so if you’ve got one of these chargers you’ve got all the tools needed to make it a standalone. Just make sure you know when to stop.

Fail of the Week: The Case of the Curiously Colored Streetlights

9 Octubre 2024 at 20:00

What color are the street lights in your town? While an unfortunate few still suffer under one of the awful colors offered by vapor discharge lamps, like the pink or orange of sodium or the greenish-white of mercury, most municipalities have moved to energy-saving LED streetlights, with a bright white light that’s generally superior in every way. Unless, of course, things go wrong and the lights start to mysteriously change colors.

If you’ve noticed this trend in your area, relax; [NanoPalomaki] has an in-depth and surprisingly interesting analysis of why LED streetlights are changing colors. After examining a few streetlights removed from service thanks to changing from white to purple, he discovered a simple explanation. White LEDs aren’t emitting white light directly; rather, the white light comes from phosphors coating the underlying LED, which emits a deep blue light. The defunct units all showed signs of phosphor degradation. In some cases, the phosphors seemed discolored, as if they experienced overheating or chemical changes. In other LEDs the phosphor layer was physically separated from the backing, exposing the underlying LEDs completely. The color of these damaged modules was significantly shifted toward the blue end of the spectrum, which was obviously why they were removed from service.

Now, a discolored LED here and there does not exactly constitute a streetlight emergency, but it’s happening to enough cities that people are starting to take notice. The obvious solution would be for municipalities to replace the dodgy units Even in the unlikely event that a city would get some compensation from the manufacturer, this seems like an expensive proposition. Luckily, [NanoPalomaki] tested a solution: he mixed a wideband phosphor into a UV-curable resin and painted it onto the lens of each defective LED in the fixture. Two coats seemed to do the trick.

We have to admit that we have a hard time visualizing a city employee painstakingly painting LEDs when swapping out a fixture would take an electrician a few minutes, but at least it’s an option. And, it’s something for hobbyists and homeowners faced with the problem of wonky white LEDs to keep in mind too.

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