20kW Light Is As Bright As You’d Expect

July 28, 2016 by Gerrit Coetzee 37 Comments

[Photonicinduction] purchased a very very bright light. This 20,000 Watt half meter tall halogen will just about light the back of a person’s skull with their eyes closed. These are typically used to light film sets.

Most people couldn’t even turn such a light on, but [Photonicinduction] is a mad scientist. Making lightning in his attic, it’s easy to mentally picture him as the villain in a Sherlock Holmes novel. Luckily for us, if he has any evil tendencies, they are channeled into YouTube videos.

He gives a good description of the mechanical and electrical properties of the light. The body is as one would expect for an incandescent light. A glass filament envelope with the filaments supported within. The envelope is evacuated and filled with an appropriate gas. This light is dangerous enough that the outside must be thoroughly cleaned of fingerprints to keep a hot-spot from forming, which could cause the lamp to explode.

After some work, he managed to convince himself that the filaments within were not, in fact, garage door springs, and gave a demonstration of their properties. For example, their resistance goes up as they are heated. In order to keep from tripping the power supply, filaments this large must be preheated. Failure to do so passes a very large number of amps.

The next step was to hook the lamp up to his home-made 20 kW power supply. He gives a good demonstration of just how bright it is. Within seconds he’s sweating from the heat and definitely can’t even open his eyes to see with the tiny sun occupying the center of his abode. Video after the break.

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DIY Smart Home Device Means No More Fumbling In The Dark

July 27, 2016 by James Hobson 24 Comments

Smart home tech is on the rise, but cost or lack of specific functionality may give pause to prospective buyers. [Whiskey Tango Hotel] opted to design their own system using a Raspberry Pi and Bluetooth device connectivity. Combining two ubiquitous technologies provides a reliable proximity activation of handy functions upon one’s arrival home.

The primary function is to turn on a strip of LEDs when [Whiskey Tango Hotel] gets home to avoid fumbling for the lights in the dark, and to turn them off after a set time. The Raspberry Pi and Bluetooth dongle detect when a specified discoverable Bluetooth device comes within range — in this case, an iPad — after some time away. This toggles the Pi’s GP10 outputs and connected switching relay while also logging the actions to the terminal and Google Drive via IFTTT.

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Incredible Luminosity In A Portable Package

July 7, 2016 by James Hobson 25 Comments

If you’ve ever wanted to bring the brightest day into the blackest night, this flashlight shall give you sight. With a 100W LED array powered by up to 32V, this thing is exceedingly bright — it clocks in at about 9000 lumens! But the best part is that all every little detail of the build was documented along the way so that we can tag along for the ride.

The all-aluminium case houses the LEDs and their heat sink, voltage regulator and display, the AD and DC adapter and converter boards and their connectors, and fans to ensure adequate ventilation. It’s powered by a custom-assembled 6400 mAh 11.1V lipo battery or DC 20V 10Amp power supply via XLR for rugged, locking connection. The battery pack connection was vacuum formed for quick-swapping, and the pack itself will sound off an alert if any of the three batteries inside the pack run out of power. A nifty added feature is the ability to check the remaining charge — especially useful if you’re looking to bring this uncommonly powerful flashlight along on camping trips or other excursions.

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Graphene Optical Boom Emits Light With No Diode

June 19, 2016 by Al Williams 38 Comments

When a supersonic aircraft goes faster than the speed of sound, it produces a shockwave or sonic boom. MIT researchers have found a similar optical effect in graphene that causes an optical boom and could provide a new way to convert electricity into light.

The light emission occurs due to two odd properties of graphene: first, light gets trapped on the surface of graphene, effectively slowing it down. In addition, electrons pass through at very high speeds. Interestingly, the speeds are nearly the same–that is, electrons and trapped light travel at almost the same speed. The researchers found a way to make the electrons move faster than the speed of light (in the graphene) and thus created Cerenkov emissions. Because of the structure of graphene, the resulting light is intense and tightly focused.

The researchers speculate that this technique could be important in building graphene-based optical chips. We’ve talked about mixed graphene and semiconductor chips before. Graphene is pretty exotic stuff. It can even fold itself.

Don’t Take Photos Of Your Arduino 101 Either, It’s Light Sensitive

May 5, 2016 by Gerrit Coetzee 41 Comments

Wafer level chips are cheap and very tiny, but as [Kevin Darrah] shows, vulnerable to bright light without the protective plastic casings standard on other chip packages.

We covered a similar phenomenon when the Raspberry Pi 2 came out. A user was taking photos of his Pi to document a project. Whenever his camera flash went off, it would reset the board.

[Kevin] got a new Arduino 101 board into his lab. The board has a processor from Intel, an accelerometer, and Bluetooth Low Energy out of the box while staying within the same relative price bracket as the Atmel versions. He was admiring the board, when he noticed that one of the components glittered under the light. Curious, he pulled open the schematic for the board, and found that it was the chip that switched power between the barrel jack and the USB. Not only that, it was a wafer level package.

So, he got out his camera and a laser. Sure enough, both would cause the power to drop off for as long as the package was exposed to the strong light. The Raspberry Pi foundation later wrote about this phenomenon in more detail. They say it won’t affect normal use, but if you’re going to expose your device to high energy light, simply put it inside a case or cover the chip with tape, Sugru, or a non-conductive paint to shield it.

EDIT: [Kevin] also tested it under the sun and found conditions in which it would reset. Videos after the break.

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Aquarium Light Mimics The Outdoor Sky

March 24, 2016 by James Hobson 5 Comments

[OlegZero] has some pet fish in his basement, and decided to work on a little project for them — an aquarium light that mimics the outdoors. He calls it the FishLight project.

His goal was to create a light panel that could imitate the color of the outdoor sky (approximately) using an RGB LED strip. During normal operation, the LEDs cycle through the colors of day, from dusk to dawn using an ATmega88 microcontroller. After his girlfriend saw what it could do, she quickly came up with the idea to add a cityscape to the background to turn it into a piece of attractive decor for their home.

Still fail to see the point of going to this much effort for a few fish? Well, besides it turning into a rather nice artistic light for their basement, the concept can be applied to other animals as well. Like encouraging chickens to produce more eggs by making the days “longer” with artificial light. As it turns out chickens produce less eggs when the days get shorter — an easy fix with something like this!

Gigabit Ethernet Through The Air

March 10, 2016 by Elliot Williams 70 Comments

There are a couple of really great things about transmitting data using light as the carrier. It can be focused so that it doesn’t spill all over the neighborhood like radio signals do — giving it both some security against eavesdropping and preventing one signal from stepping on another’s toes. And while you can modulate radio signals up nearly to the carrier frequency, the few gigahertz we normally use for radio just won’t cut it for really high bit rates. Light gets you terahertz.

The Koruza project is an open-source, “inexpensive” system that aims to transmit 1 Gb/sec over distances around 100 meters, using modulated infrared light. The intended use-case is urban building-to-building communication at speeds that would otherwise require laying fiber-optic cables. Indeed, the system piggy-backs on existing fiber-optic equipment to get the job done, but the hard part is aligning the units to get maximum signal from point A to point B.

Koruza does this by including motorized lenses on the 3D-printed chassis. You make a rough alignment with a visible green laser, and then fine-tune the IR beams from a web console where you get immediate feedback on how the received signal strength is changing. Both Koruza boxes have a Raspberry Pi inside and use normal networking for calibration and signal-strength statistics. It’s a really neat system, and it’s fully DIY’able except for the commodity fiber-optic bits.

We’ve always had a soft-spot in our heart for transmitting data over light beams. The Ronja project has been doing so since 2001, and over longer distances, with completely DIY hardware, if at a slower bitrate. And now that Li-Fi seems to be getting traction, we might see an unfocused equivalent running inside our homes.

Thanks [Pavel] for the tip!