How Constant Is Your Choice Of Lights?

The move from incandescent filament lamps to fluorescent, and then LED lighting over the last couple of decades has delivered immense benefits in terms of energy saving, but had brought with it problems for people sensitive to flicker or to too much of a particular set of wavelengths. It’s not always easy to quantify the propensity of a particular light for flickering. So [kk99] has produced an instrument returning a visual indication of its quality.

At its heart is an M5Stick ESP32 development platform, and a TSL250R light sensor hooked up to one of the ESP’s internal ADCs. The flicker waveform is displayed on the screen as a simple oscillograph, and a Fourier transform is performed to extract its frequency. The result is an extremely accessible and compact instrument, showing the suitability of the M5Stick form factor for such designs. So far we’ve only brought you an M5Stick in a password keeper, but we look forward to seeing more projects featuring it.

You can see the light flicker meter in action in the video below the break.

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Diurnal Reef Control Realistically Insolates Your Aquarium

[Phillip]’s project is not just great for learning new words, it also shows just how complex natural systems can be. 

As we know from news around the word, reefs are delicate systems prone to damage from just about any imaginable threat. Escaped aquarium fish, sunscreen, and the wayward feet of well meaning tourists to name a few. So it’s no wonder that aquarium hobbyists sometimes go to incredible lengths to simulate the natural environments these creatures live in.

While [Phillip] is still tinkering with his designs for this project, we found the data he included really interesting. His goal is to be able to plug in any coordinate on the earth and have the lights replicate the location. That includes not just the sun, but also the light from the moon as many corals seem to only spawn during certain tides. Of course no LED is perfect so he’s even experimenting with putting light sensors under the water to provide a feedback loop to make it perfect.

We really like the ambition of this project and we hope he continues.

Making Your Own Caving Headlamp

An important distinction between equipment used for caving, climbing, biking, and other outdoor activities is the level of stress that’s generally applied. For instance, while climbing helmets are built to withstand the impact of sharp rocks, they’re not made to protect a biker’s head from suddenly hitting the ground. Likewise, while camping headlamps may be able to survive a light rainfall, they’re probably not made to shine at the 800 lumens after being submerged underwater.

[LukeM] built himself a caving headlight, after being “fed up with what was available on the market”. While his project is a bit older, it’s still pretty helpful for any newer hobbyists looking to try their hand at building a custom headlamp. Many cavers have to carry around a few primary – one main light for general visibility and a secondary light for focusing on specific objects. These are typically worn on the helmet, attached somehow to prevent the light source from falling off mid-climb. From tricky operations, varying distances, cost, and ease of battery replacement, there are a number of reasons why a caver might want to build their own customizable head lamp.

The result is rugged, waterproof, reliable, bright enough to supplement flashes in caving photos and also dim enough for general use (30-700 lumens). It has options for wide and narrow beams, displays a neutral to warm color, and is relatively upgradeable without too much trouble. At the same time, it’s also fairly compact, with all of the components packed inside of a short section of 3″x2″ aluminum tubing, protected at the back and front by aluminum and acrylic backings. The LEDs used are four Cree XP-E R2 bin LEDs and a hipFlex driver from TaskLED with programmable settings for max output, thermal protection temperature, warning voltage, and lighting modes. I’m personally already smitten with the level of customizability of this build.

On top of all of that, it’s been cave tested and approved!

Conductive Origami Lights Up Your Life

It’s taken mobile phone developers years to develop electric circuits and displays that can fold. Finally he first few have come to market — with mixed reviews and questionable utility at best. For all that R&D, there are a lot of other cases where folding circuitry might have been more useful than it seems these handsets have been. One of those is conductive origami, which in this case allows for light fixtures that turn themselves on as they are unfolded.

This conductive origami is produced by [Yael Akirav] using a 3D printer to deposit the conductive material onto fabric. From there, the light fixture can be unfolded into its final position and turned on. This isn’t just a decorative curiosity though, the design of the folding material actually incorporates the ability to turn itself on as it is unfolded. One device brightens itself as it is slowly unfolded.

This is an interesting take on foldable circuits in general, especially with some of the functionality incorporated into the physical shape of the material. We’ve seen conductive elements embroidered into fabric before, but this takes it to a new level. Surely there are more applications for a device like this that we will see in the future as well.

Thanks to [t42] for the tip!

Great Artificial Daylight Via Broken TVs

[DIY Perks] has long been a fan of lights that accurately mimic real daylight. Often choosing high-quality LEDs for his projects, lately he’s taken a different tack – using broken televisions to produce attractive home lighting solutions.

The hack involves removing the backlight from the damaged television or monitor. These have a powerful white light inside, but the real key is that they also features a Fresnel lens. This helps the backlight appear very similar to a real skylight, due to the way it scatters light around the room.

Due to the difficulty of driving most LED and CCFL backlights, the project strips the original lighting out and replaces it with a set of high-CRI LED strips readily available off eBay. These are easily driven from 12 volts and give a white light more similar to actual daylight compared to most backlights. With the LEDs in place, the monitor’s original diffusers and Fresnel lens are put back in place, and the light is finished off with an aluminium frame.

Fitted to an angled ceiling, the light really does look as if actual sunlight is streaming through a window on a rainy day. It’s a pleasant effect that does a great job of lighting a room, and we suspect it would be excellent for general video work, too. [DIY Perks] is no stranger to a good studio light build, after all. Video after the break.

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Old CDs Create A Haunting Rainbow Vortex

The 1960s were, in Western culture, a time of great social and political upheaval, and the dawning of the psychedelia subculture. This resulted in an art style consisting of bright colours in wild, shifting designs. [Afraser-kruck] has built a device capable of generating beautiful rainbow light patterns, which he calls Mesmer-Eyes.

Unnerving, to say the least.

The device uses two CDs, stripped of their reflective coating. This leaves the plastic layer behind, which appears to be acting as a circular diffraction grating. By passing light from a flashlight through a CD, a dazzling rainbow vortex is created, and the effect is even further improved by adding a second disc. The patterns can be moved and shifted by changing the distance between the discs themselves, as well as the flashlight. This is achieved through the use of a sled that slides on PVC pipes, holding each individual element.

It’s a build of a kind we haven’t seen before, and is put to good use as a creepy Halloween decoration, imitating the famous Cheshire Cat. It’s one we can’t wait to tackle ourselves, and we wonder how difficult it would be to turn it into a projection, or a larger scale design.

Creepy eyes remain a Halloween staple; we’ve featured them before. Video after the break.

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A Work Light For Hacker Events

If you’ve ever attended a hacker camp, you’ll know the problem of a field of tents lit only by the glow of laser illumination through the haze and set to the distant thump of electronic dance music. You need to complete that project, but the sun’s gone down and you didn’t have space in your pack to bring a floodlight.

In Days of Yore you might have stuck a flickering candle in an empty Club-Mate bottle and carried on, but this is the 21st century. [Jan-Henrik] has the solution for you, and instead of a candle his Club-Mate bottle is topped a stack of LED-adorned PCBs with a lithium-ion battery providing a high intensity downlight. It’s more than just a simple light though, it features variable brightness and colour temperature through touch controls on the top surface, as well as the ability to charge extra 18650 cells. At its heart is an STM32F334 microcontroller with a nifty use of its onboard timer to drive a boost converter, and power input is via USB-C.

We first saw an early take on this project providing illumination for a bit of after-dark Hacky Racer fettling at last year’s EMF 2018 hacker camp, since then it has seen some revisions. It’s all open-source so you can give it a go yourself if you like it.