The Postmortem Password Problem

Death and passwords: two things we just can’t avoid. With so much of our lives tied up in cloud services nowadays, there’s good reason to worry about what happens to these accounts if we drop dead tomorrow. For many of us, important documents, photos, financial information and other data will be locked behind a login prompt. Your payment methods will also expire shortly after you have, which could lead to data loss if not handled promptly. The most obvious way to address this is to give a trusted party access in case of emergency.

A Bad Solution

Let’s start with the simplest solution: using the same password everywhere.  Great, all you need to do is put this on a Post-it note, stuff it in an envelope, and let someone know where to find it. Unfortunately, using a single password for many services is a terrible idea. Password breaches happen, and if you’re using a single password across the internet, they can be disastrous.

Password breaches are usually the result of an attacker finding a vulnerability that allows reading password data from an application’s database. Odds are high that your information has been leaked in one of these breaches. You can check if your email is on a list of known breaches with Have I Been Pwned. Don’t feel bad if you’ve been pwned, my email shows up on six different breaches, and this service only indexes publicly known breaches!

Depending on the competency of the company that was breached, your password may have been stolen in a few different formats. In the worst case, the passwords were stored as-is (i.e., cleartext), and the breach contains your actual password. Nowadays, storing passwords in cleartext is never considered acceptable. A hash of the password is stored instead. Attackers need to use a tool like hashcat to try to recover the passwords via brute force hash cracking. This is slow for complex passwords, but is always getting faster as GPUs improve.

So we really need to use different passwords everywhere, or our Tumblr account from 2013 could give access to our bank account. Given the large number of services we use and our inability to remember passwords, we’re going to need to use a password manager. Continue reading “The Postmortem Password Problem”

New Part Day: DLP300s The Next Big Thing For Low Cost Resin Printing?

The majority of non-SLA resin 3D printers, certainly at the hacker end of the market, are most certainly LCD based. The SLA kind, where a ultraviolet laser is scanner via galvanometers over the build surface, we shall consider no further in this article.

What we’re talking about are the machines that shine a bright ultraviolet light source directly through a (hopefully monochrome) LCD panel with a 2, 4 or even 8k pixel count. The LCD pixels mask off the areas of the resin that do not need to be polymerised, thus forming the layer being processed. This technique is cheap and repeatable, hence its proliferance at this end of the market.

They do suffer from a few drawbacks however. Firstly, optical convergence in the panel causes a degree of smearing at the resin interface, which reduces effective resolution somewhat. The second issue is one of thermal control – the LCD will transmit less than 5% of the incident light, so for a given exposure at the resin, the input light intensity needs to be quite high, and this loss in the LCD results in significant internal heating and a need for active cooling.  Finally, the heating in the LCD combined with intense UV radiation degrades the LCD over time, making the LCD itself a consumable item.

Continue reading “New Part Day: DLP300s The Next Big Thing For Low Cost Resin Printing?”

Test For 3D Printer Runaway

A few 3D printers have had a deserved reputation for bursting into flames. Most — but apparently not all — printers these days has firmware that will detect common problems that can lead to a fire hazard. If you program your own firmware, you can check to see if you have the protection on, but what if you have a printer of unknown provenance? [Thomas] shows you how to check for a safe printer. Also check out his video, embedded below.

The idea is to fake the kind of failures that will cause a problem. Primarily, you want to have the heaters turned on while the thermistor isn’t reading correctly. If the thermistor is stuck reading low or is reading ambient, then it is possible to just drive the heating element to get hotter and hotter. This won’t always lead to a fire, but it could lead to noxious fumes.

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Building A Hundred-Year-Old Radio Transmitter

Our Hackaday team is spread across the world, but remains in easy contact through the magic of the Internet. A number of us hold amateur radio callsigns, so could with a bit of effort and expenditure do the same over the airwaves. A hundred years ago this would have seemed barely conceivable as amateurs were restricted to the then-considered-unusable HF frequencies.

Thus it was that in December 1921 a group of American radio amateurs gathered in a field in Greenwich Connecticut in an attempt to span the Atlantic. Their 1.3 MHz transmitter using the callsign 1BCG seems quaintly low-frequency a hundred years later, but their achievement of securing reception in Ardrossan, Scotland, proved that intercontinental communication on higher frequencies was a practical proposition. A century later a group from the Antique Wireless Association are bringing a replica transmitter to life to recreate the event.

A free-running oscillator is today rarely seen in a radio transmitter, but at the time their single-tube Colpitts oscillator using a UV-204 transmitting tube would have been considered a stable source. That fed a 1KW power amplifier using three more UV-204s in parallel, which in turn fed a Marconi-style T antenna design with an earth counterpoise of multiple radial wires. The replica was originally built for an event in 1996, and substitutes the similar 204A tube for the now unobtainable UV-204. Even then, hundred-year-old tubes are hard to find in 2021, so they could only muster a single working example for the PA.

All in all it’s a very interesting project, and one of which we hope we’ll hear more as the anniversary approaches. If we can get the transmission details we’ll share them with you, and let’s see whether the same distances can be traversed with the more noisy conditions here in 2021.

To demonstrate how advanced this transmitter was for 1921, take a look at the Alexanderson alternator, its mechanical contemporary.

One Wood Ring To Rule Them All

[Olivier Gomis] did not have access to the fires of Mount Doom to forge a large replica of the One Ring, so he had to settle for patience, maple, and a wood lathe. It does have the added convenience of not needing to fire to expose its true nature, just angry pixies from a wall socket.

[Olivier] made the ring in separate inner and outer sections from 72 blocks of maple. The blocks were glued together in 12-sided rings, and stacked in layers to achieve the desired width. The surfaces were cut smooth and thinned out on a wood lathe, and an internal channel was created for LED strips. The Black Speech was cut through the walls of both the inner and outer surfaces using a manual router. Using the ring itself as a former, he made a wooden base for the router to allow it to slide across the surface without wobbling.

The inside wall was cut into sections and glued into a recess in the external portion. The inscriptions were covered with a maple veneer, which still allows it to be visible when the internal LEDs are switched on. The wiring runs from the base of the stand through an S-shaped stem that was made from layers of veneer clamped in a former. A total of 53 hours of painstaking effort went into this work of art, but the end product would make any hardcore Lord of the Rings fan envious.

For more LOTR-themed hacks, check out the secret door to the Mines of Moria secret door, and a sword that glow blue in the presence of unsecured WiFi.

Continue reading “One Wood Ring To Rule Them All”

3D Printing Your Own Sturdy Lens Caps

Lens caps are important for protecting expensive camera lenses from damage. Dust, grit, and other nasty things will all quickly spoil the quality of a shot, and can even permanently damage a lens if you’re unlucky. However, lens caps are also lost quite easily. Thus, it’s useful to be able to make your own, and [DSLR CNC DIY] has the low down on how to do it. 

The benefit of printing your own lens caps is customization. No matter the oddball size and shape of your lens, when you’re 3D printing your own cap, you can design it to fit. The video also shows off the benefits of being able to embed text right into the body of the cap, so you’re never confused as to which cap goes with which lens. The caps use the metal lever from a binder clip in order to provide the clamping force necessary to hang on to the lens. It’s an improvement over some living-hinge designs that grow weaker over time.

Overall, if you’ve got a bunch of lenses that need a new cap, this could be the project for you. It’s also likely much cheaper and easier than hunting down replacement caps for obscure lenses online. Alternatively, contemplate what you could do with fancy lens adapters. Video after the break. Continue reading “3D Printing Your Own Sturdy Lens Caps”

Simple Tactile Drawing Pad Is Quite Impressive

Everyone needs to be able to communicate and express themselves, even people with blindness or low vision. Embossing paper with some kind of stylus is a popular, low-tech option, but there’s one big problem: pressing paper from the top leaves a dent, and so letters have to either be written backwards or else felt-read backwards. For this year’s Hackaday Prize, [Subir Bhaduri] is working on a fantastic tool that embosses positively, and from the top side of the paper.

Positive emboss marks from a clever pantograph and a pair of stylii.Here’s how it works: a pointed stylus pushes upward from the underside and meets up with a concave receiver on the top side through the paper. The two stylii move in concert thanks to the pantograph-inspired parallelogram setup, which we imagine would make it easier for someone with low vision to keep their bearings as they move around the page.

The video below shows prototype #2, which is the first one that worked. Well, it works, but [Subir] says it needs improvement, so prototype #3 is in the sketching stage now. [Subir] is planning to fix the paper in place somehow and also figure out how to keep the pantograph arms out of the user’s way.

Pantographs are used for all sorts of things, but the sweetest use we’ve seen was to carve messages into chocolate hearts.

Continue reading “Simple Tactile Drawing Pad Is Quite Impressive”