Disappearing Writing With UV Laser Reveals Whitening Agents In Myriad Products

August 6, 2019 by Zoe Skyforest 11 Comments

Many a budding maker has experimented with invisible inks, with a wide variety of solutions having a viable set of properties for this purpose. However, [Ben Krasnow] stumbled upon a different method entirely when tinkering with a UV laser.

The effect is subtle, but remains visible for several minutes.

The laser in question was a MNL100 UV laser, configured to produce nanosecond-scale 20 kW pulses at up to 24 Hz, operating at wavelength of 337 nm, deep in the ultraviolet. After piping the laser light through an optical fiber and aiming it at some regular white paper, dark marks were observed, which disappear without a trace over the course of a few minutes.

Upon investigation, the dark marks seemed to be the result of fluorescent whitening agents in the paper. It appears they are overloaded or otherwise changed chemically by the laser, and slowly return back to normal over time. Further experiments showed that hydrogen peroxide was able to remove the marks instantly, and an argon atmosphere slowed the rate at which the marks faded.

It’s an interesting look at an odd chemical effect, with the benefit of a well-equipped optics lab to analyse what’s going on. Following the phenomenon down the rabbit hole leads to some tips on how to extract fluorescent additives from common laundry detergent. Be it paper, plastic, or textile, if it looks really bright white to your eye it probably contains stilbene organic compounds as optical brighteners, a hidden trait you never actually thought about before. Video after the break.

Continue reading “Disappearing Writing With UV Laser Reveals Whitening Agents In Myriad Products” →

A Trillion Trees – How Hard Can It Be?

August 5, 2019 by Zoe Skyforest 167 Comments

Data from 2016 pegs it as the hottest year since recording began way back in 1880. Carbon dioxide levels continue to sit at historical highs, and last year the UN Intergovernmental Panel on Climate Change warned that humanity has just 12 years to limit warming to 1.5 C.

Reducing emissions is the gold standard, but it’s not the only way to go about solving the problem. There has been much research into the field of carbon sequestration — the practice of capturing atmospheric carbon and locking it away. Often times, this consists of grand plans of pumping old oil wells and aquifers full of captured CO2, but there’s another method of carbon capture that’s as old as nature itself.

As is taught in most primary school science courses, the trees around us are responsible for capturing carbon dioxide, in the process releasing breathable oxygen. The carbon becomes part of the biomass of the tree, no longer out in the atmosphere trapping heat on our precious Earth. It follows that planting more trees could help manage carbon levels and stave off global temperature rises. But just how many trees are we talking? The figure recently floated was 1,000,000,000,000 trees, which boggles the mind and has us wondering what it would take to succeed in such an ambitious program.

Continue reading “A Trillion Trees – How Hard Can It Be?” →

Make Your Own Flexible Panel Lights

August 3, 2019 by Zoe Skyforest 7 Comments

In this day and age, production values are everything. Even bottom-rung content creators are packing 4K smartphones and DSLRs these days, so if you want to compete, you’re gonna need the hardware. Lighting is the key to creating good video, so you might find a set of flexible panel lights handy. Thankfully, [DIY Perks] is here to show you how to build your own. (Video embedded below.)

The key to building a good video light rig is getting the right CRI, or Color Rendering Index. With low CRI lights, colors will come out looking unnatural or with odd casts in your videos. [DIY Perks] has gone to the effort of hunting down a supplier of high-quality LED strips in a range of different color temperatures that have a high CRI value, making them great for serious video work.

To build the flexible panel, the LED strips are glued onto a fake leather backing pad, which is then given a steel wire skeleton to enable it to be bent into various shapes. Leather loops are built into each corner of the panel as well, allowing the light to be fitted to a stand using a flexible aluminium bracket. The LEDs are slightly under-volted to help them last longer and enable them to run from a laptop power supply.

The build is one that focuses on light quality and usability, rather than just throwing a bunch of bright LEDs at the problem and calling it good. The results are great, with the panel showing a significant improvement on [DIY Perks]’s earlier builds.
Continue reading “Make Your Own Flexible Panel Lights” →

Fake Graphics Cards And How To Fix Them

August 2, 2019 by Zoe Skyforest 48 Comments

When shopping online, there’s plenty of great deals out there on modern graphics hardware. Of course, if you’re like [Dawid] and bought a GTX1050 Ti for $48 from Wish, you probably suspect it’s too good to be true. Of course, you’d be correct.

[Dawid] notes from the outset that the packaging the card ships in is unusual. While it’s covered in NVIDIA and GeForce branding, there’s no note of the model number or even the overarching series. The card is loosely packed in bubblewrap, free to bounce around in transit. Upon installation, the card reports itself as a GTX1050 Ti, but refuses to properly work with NVIDIA drivers and routinely causes a Blue Screen of Death.

Upon disassembly, it becomes apparent that the card is merely a poorly manufactured GTS450 Revision 2, over five generations older than the card it was advertised as. Thanks to the mismatch between the actual hardware and what the card reports as, the drivers are unable to properly work with the card.

For those that have been scammed, there is some hope. [Phil] has had experience with several of these cards, which similarly misreport their actual hardware. To correct this, the cards need to have their BIOS flashed to reflect reality, but the fake cards don’t work with NVIDIA’s NVFlash tool. Instead, they must be flashed manually using an EEPROM programmer. Once the cards are flashed with an appropriate BIOS, they can be used with the proper drivers and will function properly, albeit with much less performance than was advertised.

It’s an interesting insight into the state of online shopping platforms, and the old adage remains true – if it’s too good to be true, it probably is. Plus, hacking GPUs can often have great results. Video after the break.

Continue reading “Fake Graphics Cards And How To Fix Them” →

Boost Your WiFi Range With Cookware

August 1, 2019 by Zoe Skyforest 44 Comments

WiFi was the killer technology that made home networking easy. No more messing around with hubs and cables and drilling holes in walls, simply turn the devices on and hit connect. Over time the speed and range has increased, but those with larger houses or granny flats out back have suffered. There are tricks to boost range however, and some of them involve cookware.

The clever hack here is to use a metal strainer as a parabolic reflector, to capture signals and focus them onto the PCB antenna in a USB WiFi dongle. The strainer is drilled out, and a USB extension cable has its female end glued into the base. This allows the dongle to be positioned inside the strainer. For best results, the dongle should be positioned so that its antenna elements are sitting at the focal point of the parabola; this can be determined through mathematics or simply by experimenting with positions to see what gives the best signal strength.

It’s a design that is quite directional, and should help boost signals as well as block out those from unwanted stations. The build is simple, and can even be tripod mounted which helps with aiming and looks cool to boot.

For many, WiFi antenna hacks are old school, but it’s always good to keep the techniques in mind as you never know when it will come in handy to solve a new problem. Some crazy things are possible with the right gear, too.

CPAP Monitor Alerts Wearer To Malfunctions

August 1, 2019 by Zoe Skyforest 30 Comments

Continuous Positive Airway Pressure machines are a common treatment tool for sleep apnea and other respiratory issues. A common problem with their use is that the mask becomes dislodged during sleep, and thus fails to provide airway pressure to the patient. [Bin Sun] decided to take a stab at solving this problem.

The project consists of an Arduino fitted with a MPXV7002DP pressure sensor. The sensor is used to monitor the pressure in the CPAP pipes. If the pressure varies regularly, it is likely the system is working. If however, the pressure remains at a roughly constant level, that suggests the mask is no longer properly fitted to the wearer, or that there is another problem. In this event, the device sounds a buzzer to wake the wearer, alerting them to check the equipment.

It’s a simple solution to the problem, and something we’re surprised isn’t built into most CPAP machines from the factory. It’s important to be careful before modifying any medical equipment, though we see plenty of hackers taking the plunge to innovate in this area.

A Look At The Basics Of Building An Arduino Watch

August 1, 2019 by Zoe Skyforest 8 Comments

Miniaturization has made smart watches possible, even for the DIY maker to tinker with. For those just getting to grips with basic digital electronics, it can be daunting, however. For those just starting out, [陳亮] put together a handy guide to building the core of an Arduino-based watch.

The writeup starts at the beginning, going over the basic hardware requirements for a smart watch. This involves considering size, packaging and power draw, as well as the user interface. The build settles on an Arduino Pro Micro, as it uses the ATmega32U4 which eliminates secondary USB-to-serial chips, helping cut down on power consumption. A square IPS LCD display is used to display an analog-style watch face, and time is kept by a DS3231 real-time clock. A pair of small vibration sensors are used to wake the watch when the user moves their wrist to check the time.

While it doesn’t cover the final assembly into a watch-like form factor, it’s a handy guide on what it takes to build a working watch for those who are still getting their feet wet with hardware. Once you’ve got that down, it’s time to contemplate how you’ll build the sleek exterior. Naturally, a good maker has that covered, too.