streetlight

4 Articles

Fail Of The Week: The Case Of The Curiously Colored Streetlights

October 9, 2024 by 115 Comments

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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Shapeshifting Streetlights Are The Future We Want To Live In

April 18, 2021 by 32 Comments

Regular streetlights are all well and good, bathing us in the glow of their sodium, or more increasingly LED, lamps. They’re mostly rigid metal contraptions installed primarily for public safety purposes. They could be so much more, however, as the Bloomlight demonstrates.

The light consists of a flexible main stem, which can be pulled in different directions by six steel cables controlled by stepper motors. At the top, it has a shroud made of wooden slats and fabric that can bloom like a flower around its central lamp, thanks to a 3D printed mechanism. LIDAR is used to detect approaching humans, at which point the Bloomlight leans over towards them and begins to bloom open, showering them with light.

It’s a beautiful art piece from the Dutch design firm [Vouw], and one we’d love to see in person. The design reminds of this useful tentacle design. With that said, it could grow emotionally exhausting having to repeatedly ignore plaintively waving streetlights that crave human attention as you walk on through the night. Anthropomorphizing anything is usually a double edged sword.

Perhaps the neatest streetlight hack we’ve seen is way back from 2013 – using a laser diode to shut off a streetlight from a distance. Video after the break.

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Blue LED Streetlights Keeping You Awake?

October 7, 2016 by 78 Comments

If you’ve played around with “white” LEDs, you already know that there’s no such thing. There’s warm white and cool white and any numbers of whites in-between. And when white LEDs were new, the bluer “cool white” variety were significantly more prevalent.

Enough US states have swapped out their old street lights with LEDs that it may be having a measurable effect on people and on the animals around us. This is the claim in a recent position paper by the American Medical Association’s Council on Science and Public Health. (Report as PDF.)

Science strongly suggests that heavy doses of light can keep people from falling asleep, and that brighter LED streetlamps may be making the problem worse. The AMA report goes a step further, and pins extra blame on the color of the light. Blue light apparently suppresses the production of melatonin which helps you sleep at night. And it’s not just humans whose circadian rhythms are getting messed up — the effects are seen throughout the animal kingdom.

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Hacking A Streetlight With Lasers

October 24, 2013 by 109 Comments

$20, some spare parts and a bit of mischief was a small price for [Chris] to pay for a reprieve from light pollution with this remote control laser hack. The streetlight in front of his house has a sensor that faces westward, and flips the lamp on once the sun has disappeared over the horizon. As it turns out, [Chris’s] third floor window is due west of this particular lamp, meaning he takes the brunt of its illumination but also conveniently places him in a prime location for tricking the sensor.

According to [Chris], the lamp’s sensor requires two minutes of input before it will switch off and stay off for around 30 seconds before cycling on again. The lamp does not zap straight to full brightness, though; it takes at least a minute to ramp up. [Chris] recalled a hack from a few years ago that essentially used LED throwies tacked onto the sensors with putty to shut off lamps for a guerrilla drive-in movie, but the sensors on those lamps were at the base and easily accessed. [Chris] needed to reach a sensor across the block and nearly three stories tall, so he dug around his hackerspace, found a 5V 20mA laser diode, and got to work building a solution.

[Chris] 3D printed a holder for the laser and affixed it via a mounting bracket to the wall near his third floor window, pointing it directly at the street lamp’s sensor. He plugged the laser’s power supply into an inexpensive remote control outlet, which allowed him to darken the street lamp at a touch of a button. This is certainly a clever and impressive hack, but—as always—use at your own risk. Check out a quick demo video after the break.

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