Parts Bin Emergency Lights Deal With Tornado’s Aftermath

Sometimes having a deep inventory of parts in your shop is a pain – the clutter, the dust, the things you can’t rationally justify keeping but still can’t bear to part with. But sometimes the parts bin delivers and lets you cobble together some emergency lighting when a tornado knocks out your power.

It has been hard to avoid discussions of the weird weather in the US this winter. The eastern half of the country has had record warm temperatures, the west has been lashed by storms, and now December tornadoes have ripped through Texas and other parts of the south, with terrible loss of life and wide-ranging property damage. [TheTimmy] was close enough to one massive EF4 tornado to lose power on Saturday night, and after the charm of a candlelight Christmas evening wore off, he headed to the shop. He had a bunch of sealed lead acid batteries from old UPSs and a tangle of 12V LED modules, and with the help of some elastic bands and jumper clips he wired up a bunch of lights for around the house. Safer than candles by a long shot, and more omnidirectional than flashlights to boot.

The power came back before the batteries ran out of juice, so we don’t get to see any hacks for recharging batteries in a grid-down scenario. Still, it’s good to see how a deep parts bin and good mindset can make a positive impact on an uncomfortable situation. We’ve seen similar hacks before, like this hacked cordless tool battery pack or powering a TV with 18650 batteries. Be sure to share your story of epic power-outage hacks in the comments below.

Hackaday Explains: Li-Fi & Visible Light Communications

A new way to transmit data is coming that could radically change the way that devices talk to each other: LiFi. Short for Light Fidelity, LiFi uses visible light to send data, creating the link between router and device with invisible pulses of light. This type of Visible Light Communication (VLC) uses something that is present in pretty much every room: an LED lightbulb.

What is LiFi?

Li-Fi sounds like the an engineer’s fevered dream: it is fast, cheap, secure and simple to implement. Speeds of up to 10Gbps have been demonstrated in the lab, and products are now available that offer 10Mbps speed. It is cheap because it can use a modified LED lightbulb. It is secure because it only works where the light is visible: step out of the room and the signal is lost. It is simple to implement because it uses an existing technology: LEDs.

The basis of the technology is in turning the LED light on and off very fast. By switching an LED on and off millions of times a second, you can create a data signal that can be detected by a sensor, but which is invisible to the human eye. At the other end, another LED detects these pulses, and can send light pulses back in response, creating a bi-directional link. If you combine this with wired Ethernet or a WiFi network, you have an awesome combination: an Internet connection that uses visible light for the last link.

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Sudden Death Night Light Sounds Scary, Is Sweet

We have to admit that we were mislead by the title “Sudden Death: Wall Sign + Night Light”. This naturally conjured up images of deadly night lights, but the truth turned out to be a lot less fatal: [Smerfj] had two weeks to make a present for a friend’s wedding. The project was either a go or a no-go depending on the deadline — that sort of sudden death. But as we all know, deadlines have a way of bringing the motivation out of us that’s not always bad.

The night light in question is a bunch of hand-made circuits, each stuffed into a wooden slice with a letter burned on the face, spelling out [Smerfj]’s friend’s name. But to really appreciate it, you have to dig through the build details.

55461447189465844We didn’t know how to burn precise lettering into wood. [Smerfj] covered the wood in metal foil tape, then cut the letters out of the foil. Now applying the torch blackens only the part of the logs that have tape removed. Slick.

To get accurate lettering cut into the aluminum tape, [Smerfj] made an impromptu projector out of a cell phone taped to a chandelier (approximately a point light source) and a stencil suspended somewhere between the chandelier and the wood target. Naturally, this is best done in a darkened room under tight deadline pressure.

The battery holders are fantastic. Springs from commercial battery holders were soldered to enamel wire and placed in holes drilled just the width of AA batteries. With the length of the battery taken into account, channels were drilled into the wood and copper wires jammed through, holding the batteries in place, and providing the other electrical contact. Brilliant.

And finally, the free-form night light circuits are great. Fine-tuned to draw the minimum current, they’re adjusted to the specific LEDs and phototransistors that [Smerfj] had on hand. Bespoke free-form electronics in hand-blackened wood. That’s a nice gift.

Now [Smerfj] just needs nice packaging to present them in. We’re thinking DIY laser-cut boxes with interior lighting, naturally.

The LED Roundsystem

Gavin Morris has been working on his awesome sound responsive LED sculptures for a while. Technically the sculpture is an interesting application of WS2812 RGB LEDs, Raspberry Pis and a load of styrofoam cups and flower pots. However the artistic development, and inspiration for this project is equally interesting. Gavin shares his thoughts and a brief technical description of the project below.

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90,000 Lumen Flashlight Is Illuminating, Impractical And Blindingly Good

It may be better to light a single candle than to curse the darkness, but that was before [RCTestflight] came up with this: a 1000W LED flashlight that outputs about 90,000 lumens of light. That’s a lot: the best pocket LED flashlights output about 700 lumens.

[RCTestflight] built this monstrosity using ten 100-Watt LEDs, running off two RC car batteries. Each of the LEDs is connected to a sizable voltage converter and a very large heatsink that holds all of them in place. He says he gets about 8 minutes of light out of this thing, and that the heatsink gets warm after a minute or two of use. We’re not surprised: LEDs are more efficient than most other devices at converting electrical energy to light, but some always gets lost as heat.

Check out the video after the break. It’s very impressive, but this thing isn’t particularly practical as a handheld. It is big, heavy and is visible for miles. If you really want to light something up it does a great job (for a short period of time) due in part to the inclusion of a glass lens for each of the LEDs. This effectively focuses the beam on a properly distributed area. We wonder what would happen if all the beams were focused on one point? As long as you don’t cross the streams

We have covered a few more practical builds using similar LEDs, but this thing does have a certain outrageous charm, and could be useful for high-speed video, where the more light, the better.

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Akiba’s Awesome Lighting Tutorial

[Akiba] over at FreakLabs just put up a detailed tutorial outlining how to control and sequence lighting wirelessly using an Arduino and Vixen lighting sequencer software.

For those that don’t know [Akiba], he’s the guy behind Wrecking Crew Orchestra (TRON Dance) and their EL wire costumes. [Akiba] hacks on his projects at Hacker farm out in rural Japan.

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In the tutorial, he sets up a simple 6 LED circuit on a Fredboard (an Arduino compatible board with integrated breadboard). [Akiba] then describes configuring the Vixen sequencer software to control the Arduino, providing simple example code to decode the Vixen serial protocol. Finally [Akiba] shows how to use the ChibiArduino protocol stack to build a wireless illumination system.

[Akiba] has used these tools in many stage performances including with the Wrecking Crew Orchestra (shown above) and the world number 1 flair bartending crew, UPT.

This tutorial is particularly awesome, as it includes both step-by-step videos and a text reference. The videos give a great overview of the process, while the text provides a handy reference to refer to as you hack on your own illumination projects.

Thanks for the writeup [Akiba]! With Christmas just round the corner we hope to see readers using these techniques in their own festive illuminations soon!

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Full-Color Edge-Lit Laser Cut Acrylic

Edge-lit art has been around for a very long time, and most people have probably come across it in a gift shop somewhere. All it takes is a pane of transparent material (usually an acrylic sheet) with the artwork etched into the surface. Shine a light into the sheet from the edge, and refraction takes over to light up the artwork. However, this technique is almost always limited to a single pane, and therefore a single color. [haqnmaq] wanted to take this idea and make it full-color, and has written up a great Instructables tutorial on how to accomplish this.

If you want to make something like this yourself, the only thing you really need is a laser cutter and some basic electronics equipment. The process itself is so straightforward that it’s surprising that it isn’t more common. You start by taking a photo of your choice and use an image editor to break it up into three photos, one for red, one for green, and one for blue. Each of those photos is then etched into an acrylic pane with a laser cutter. When the panes are positioned in front of each other and edge-lit with their respective LEDs, a full-color image comes to life.

This isn’t the first edge-lit artwork project we’ve featured, but it definitely has the highest fidelity. Because [haqnmaq’s] technique uses three colors, you can use his tutorial to reproduce any photo you like. You could even take this a step further and create animated photos by adding more panes and lighting them up in the correct sequence!