2026-03-08 05:00:00
Although to the average person a camera lens is just that bit of glass you stick on the front of the camera to make stuff appear in focus, there’s a whole wide world out there of lens designs and modifications with enough variety to make your head spin. Some of these designs make a big impact, while others fade away again, sometimes at the whims of film makers and photographers. Prism-based anamorphic lenses are an oddity that recently [Mathieu Stern] got his hands on. (Video, embedded below.)
During the 1950s and 1960s there was a bit of a competition between anamorphic formats, which use special lenses that ‘squeeze’ a larger image so that widescreen movies could be recorded on standard 35 mm film. By using the same lens for recording and playback, the result was a mostly distortion-free image. Here the Technirama format by Technicolor who teamed up with Dutch company De Oude Delft (‘Old Delft’) to produce the prism-based Delrama lenses that fit on existing lenses for cameras and projectors.
Despite having a clearly superior, distortion-free image than the cylindrical lenses of the competition, Technirama got pushed out of the commercial market, leaving De Oude Delft to try and interest the consumer market for Delrama with 8 and 16 mm adapters. These latter are the ones that [Mathieu] got his hands on and tried out with a DSLR camera.
Troublesome with these Delrama adapters is that their silver mirrors tend to degrade over time, and they also turned out to be rather fragile, which are both things that made consumers sour on them. Another challenge was the fixed four meter focus that’s great when you’re using it with a projector, but terrible for up-close shots. All of these issues resulted in Delrama fading from the market by the 1970s until all that remains are these remnants of a format that once was used to film some of the biggest Hollywood movies.
2026-03-08 02:00:21
Instant photography is a miracle of the analog age, chemical photographs that develop in your hands moments after the shutter has been pressed. You can buy instant cameras and film from Fuji and the successor company to Polaroid, the originator of the technology, but they’re expensive. Fortunately [BoxArt] is here for those seeking a cheaper alternative, with an instant camera featuring a Raspberry Pi and a printer (Lithuanian language, Google Translate link).
It’s a fairly straightforward arrangement, with the Pi Zero and camera driving a receipt printer. There’s a nicely engineered 3D printed case, and the guts of a power bank to provide the volts for the thing. There are a set of status lights on top, and that’s it. Press the button, get a not-very-good grayscale image on curly paper.
You can of course buy off-the-shelf grayscale printing cameras from your favorite import site for much less than the cost of this camera, but we think this would probably take better pictures. Meanwhile if the original instant photography interests you, we’ve got you covered.
2026-03-07 23:00:01
We were talking about [Maya Posch]’s rant on smartphones, “The Curse of the Everything Device”. Maya’s main point is that because the smartphone, or computer, can do everything, it’s hard for a person to focus down and do one thing without getting distracted, checking their whatever feed, or getting an important push notification about the Oscars. She was suggesting tying your hands to the mast by using a device that can only accommodate the one function, like a dedicated writing tool or word processor.
[Kristina Panos] compared the all-singing, all-dancing black rectangle to an everything-device of old: the all-in-one stereo receiver with built-in tape player, record player, and not just FM, but also AM radio receiver. The point being, the hi-fi device also does a whole lot of things but isn’t similarly cursed. The tape player never interrupts your listening to the AM radio station. When the record is over, it doesn’t swap over to FM. Your agency is required.
Similarly, it’s probably not intrinsically problematic that the smartphone has a camera, a web browser, text messages, and heck even a telephone built in. It’s how they interact with each other and the user, each vying for user attention, and interrupting with popups and alarms. It’s maybe a simple matter of software! (Says the hardware guy.)
Where would a distraction-free, but fully featured, phone begin? With the operating system? It would be perverse to limit you to one app at a time, or to make switching between them more cumbersome. How about turning off notifications, and relying on changing context only when you think about it? Maybe that’s a middle ground. How do you cope with the endless distractions offered to you by your smartphone? By your main computer?
2026-03-07 20:00:55
Depending who you ask, 3D pens are silly toys or handy tools. Those who use them as tools find them handy to fill gaps in printed assemblies or to use them as a PLA or PETG-based hot glue gun for their prints. [half-baked-research] on YouTube is in the second category, but knows that welding is better than gluing — so he built himself a 3D pen designed for plastic welding.
You can weld with a regular 3D pen, and [half-baked] demonstrates that in the video. But thanks to the low-conductivity tips on commercial pens, it’s a slow, fiddly business. By using a normal 3D printer hot-end, with its conductive brass nozzle, [half-baked] is able to get a lot more heat where it’s needed. That means the plastic on either side of the weld melts for a good bond with the stuff coming out the nozzle. He’s also able to push plastic much faster with the modified extruder he’s squeezed into the hot-glue-gun looking contraption. Those two things together conspire to make the whole process go much faster than with a commercial 3D pen. He calls his build a 3D pen, but given the form factor it might be more accurate to call it a ‘plastic extrusion gun’.
Starting at around 13:38 in the video, he performs some strength tests, something we wish more YouTubers would do. He’s able to demonstrate a stronger bond with his welding pen than the normal 3D pen, and a much, much stronger join than the usual superglue. A traditional plastic weld with hot air is even stronger, but [half-baked] points out elsewhere in the video that on thin-walled prints (as opposed to the solid test articles) hot air welding can be a very dicey business. Pen-welding offers much greater control, so is an interesting technique to keep in mind.
Alas, [half-baked-research] apparently still considers this idea too half-baked to release the design. If you don’t have time to wait or reinvent this particular wheel, we featured a much simpler implementation of a similar idea years ago, using PLA in a hot glue gun. If that won’t work for you — maybe you aren’t a fan of PLA — perhaps you might try friction welding with filament.
2026-03-07 17:00:58
Modern-day receivers are miracles of digital audio and video processing, but compared to their more analog brethren, they can come with a host of new and fascinating faults. The Onkyo TX-SA806 and SR806 receivers were released back in 2008, with [Tony359] recently getting the latter variant in for repair. Described as having weird digital distortion on the audio outputs, this particular issue got fixed by recapping the PCB with all the digital processing in the first video on this receiver, but this left the second issue unaddressed of a persistent hum, which is the topic of the second video on this repair.
With the easy fix of recapping of the digital board already tried, next was a deep-dive into the receiver’s schematics to figure out where this low-frequency hum was coming from. With it sounding very much like mains frequency hum bleeding through, this was the starting point. Presumably somewhere on the power rails the normal filtering had broken down, so all rails had to be identified and checked for this interference.
With ripple on the 10V and 12V rails as well as the others seemingly in order, it wasn’t clear where the 100 Hz hum was coming from, but people on the BadCaps forum offered some help. After some back and forth it was deduced that the problem was the +15 VA rail, with heavy ripple on it due to a dead capacitor on the +22 V rail that comes straight from a transformer.
For some reason Onkyo’s engineer and/or bean counters had decided that installing an 85°C electrolytic capacitor on the opposite PCB side of a bridge rectifier was a genius idea, which turned out to be not quite the case. With the capacitor eventually giving up on life, the mains hum was allowed to freely pass onto the analog voltage rail and from there into the outputs.
Of course, getting to the target C5662 capacitor was anything but easy, as these modern receivers are tightly packed sandwiches of PCBs, requiring basically a full disassembly. Upon getting to C5662 it was clear that the capacitor was bad, being visibly bulged. Despite being a quality Japanese Nichicon capacitor, such an abusive environment was simply too much. With more similarly poorly spec’ed capacitors at risk of the same fate, these were all replaced with 105°C rated electrolytics.
Perhaps unsurprisingly this fixed the mains hum on the outputs, returning this receiver back to full functionality. In some ways it’s good to know that even with these modern receivers the most typical fault is still due to electrolytic capacitors.
2026-03-07 14:00:01
Can you remotely unlock an encrypted hard disk? [Jyn] needed to unlock their home server after it rebooted even if they weren’t home. Normally, they used Tailscale to remote in, but you can’t use tailscale to connect to the machine before the hard drive decrypts, right? Well, you can, sort of, and [Jyn] explains how.
The entertaining post points out something you probably knew, but never thought much about. When your Linux box boots, it starts a very tiny compressed Linux in RAM. On [Jyn’s] machine using Arch, this is the initramfs.
That’s not news, but because it is an actual limited Linux system (including systemd), you can add tools to it. In this case, adding dropbear (an ssh server) and Tailscale to the limited boot-time Linux.
Doing this in the most straightforward way presents several issues related to security. However, using a few configuration items, you can limit it to showing the unlock screen and nothing else.
The only limitation is that the setup, as written, will only work with an Ethernet interface. WiFi should be possible, but getting the wireless network up in this environment would likely be challenging.
You could probably set this up with WireGuard or even an ssh tunnel if you were adventurous.
