Powering On A 1985 Photophone CP220 Videoconference System

January 6, 2026 by Maya Posch 9 Comments

The concept of remote video calls has been worked on since Bell’s phone company began pitching upgrading from telegrams to real-time voice calls. It wasn’t until the era of digital video and real-time video compression that commercial solutions became feasible, with the 1985 Image Data Corporation Photophone CP220 being an early example. The CP220 is also exceedingly rare due to costing around $25,000 USD when adjusted to inflation. This makes the teardown and repair on the [SpaceTime Junction] channel a rather unique experience.

Perhaps the coolest part of the device is that the manual is integrated into the firmware, allowing you to browse through it on the monochrome CRT. Unfortunately after working fine for a while the device released the magic smoke, courtesy of the usual Rifa capacitors doing their thing. This is why a full teardown was necessary, resulting in the PSU being dug out and having said capacitors swapped.

After this deal the device powered on again, happily accepting a video input and saving screenshots to the floppy drive before it was replaced with a FDD emulator running FlashFloppy firmware. Unfortunately no video call was attempted, probably because of the missing camera and having to set up a suitable POTS landline for the built-in modem. Hopefully we’ll see that in an upcoming video to see what we common folk were missing out on back in the day.

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Close-Up Look Reveals That Raindrops Are More Erosive Than Assumed

January 5, 2026 by Maya Posch 18 Comments

Whenever it rains, people generally don’t look too closely at what the drops do exactly when they hit a surface. We generally assume that stuff will get wet and depending on the slope of the surface it’ll run off downhill at some point, probably in a nice, neat flow. Of course, reality doesn’t work that way, as Swiss researchers recently found when they pointed high-speed cameras at simulated raindrops. Their findings were published recently in Applied Physical Sciences, which is sadly paywalled, but the summary article over at phys.org provides some details, including a video.

The researchers set up a 1.2 meter long dry silicate sand surface with a 30° slope on which the drops were released. In the top image you can see two stills of the result, with the full video showing the drops turning into either peanut- or doughnut-shaped forms that gathered significant amounts of sand grains. These grains mix with the water, allowing a single drop to erode significant amounts of material from a slope, more than was previously assumed in existing soil erosion models.

Beyond erosion, these findings also offer insights for similar dynamics in other fields, all thanks to a group of researchers who got curious during a rainy walk and decided to take a closer look.

GitHub Disables Rockchip’s Linux MPP Repository After DMCA Request

January 5, 2026 by Maya Posch 64 Comments

Recently GitHub disabled the Rockchip Linux MPP repository, following a DMCA takedown request from the FFmpeg team. As of writing the affected repository remains unavailable. At the core of this issue is the Rockchip MPP framework, which provides hardware-accelerated video operations on Rockchip SoCs. Much of the code for this was lifted verbatim from FFmpeg, with the allegation being that this occurred with the removal of the original copyright notices and authors. The Rockchip MPP framework was further re-licensed from LGPL 2.1 to the Apache license.

Most egregious of all is perhaps that the FFmpeg team privately contacted Rockchip about this nearly two years ago, with clearly no action taken since. Thus FFmpeg demands that Rockchip either undoes these actions that violate the LGPL, or remove all infringing files.

This news and further context is also covered by [Brodie Robertson] in a video. What’s interesting is that Rockchip in public communications and in GitHub issues are clearly aware of this license issue, but seem to defer dealing with it until some undefined point in the future. Clearly that was the wrong choice by Rockchip, though it remains a major question what will happen next. [Brodie] speculates that Rockchip will keep ignoring the issue, but is hopeful that he’ll be proven wrong.

Unfortunately, these sort of long-standing license violations aren’t uncommon in the open source world.

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Modifying A QingPing Air Quality Monitor For Local MQTT Access

January 4, 2026 by Maya Posch 7 Comments

The QingPing Air Quality Monitor 2 is an Android-based device that not only features a touch screen with the current air quality statistics of the room, but also includes an MQTT interface that normally is used in combination with the QingPing mobile app and the Xiaomi IoT ecosystem. Changing it to report to a local MQTT server instead for integration with e.g. Home Assistant can be done in an official way that still requires creating a cloud account, or you can just do it yourself via an ADB shell and some file modifications as [ea] has done.

By default these devices do not enumerate when you connect a computer to their USB-C port, but that’s easily resolved by enabling Android’s developer mode. This involves seven taps on the Device Name line in the About section of settings. After this you can enter Developer Options to toggle on Debug Mode and Adbd Debugging, which creates the option to connect to the device via USB with ADB and open up a shell with adb shell.

From there you can shoot off the QingSnow2 app and the watchdog.sh that’s running in the background, disable IPv6 and edit /etc/host to redirect all the standard cloud server calls to a local server. Apparently there is even SSH access at this point, with root access and password rockchip. The MQTT configuration is found under /data/etc/ in settings.ini, which is used by the QingPing app, so editing redirects all that.

Of course, the device also queries a remote server for weather data for your location, so if you modify this you have to provide a proxy, which [ea] did with a simple MQTT server that’s found along with other files on the GitHub project page.

The Nintendo 64DD, an N64 add-on released only in Japan in 1999.

Exploring Nintendo 64DD Code Remnants In Ocarina Of Time

January 4, 2026 by Maya Posch 15 Comments

What if you took a Nintendo 64 cartridge-based game and allowed it to also use a large capacity magnetic disc format alongside it? This was the premise of the Nintendo 64DD peripheral, and the topic of a recent video by [Skawo] in which an archaeological code dig is performed to see what traces of the abandoned product may remain.

The 64DD slots into the bottom of the console where the peripheral connector is located, following which the console can read and write the magnetic discs of the 64DD. At 64 MB it matched the cartridge in storage capacity, while also being writable unlike cartridges or CDs. It followed on previous formats like the Famicom Disk System.

For 1998’s Game of the Year title The Legend of Zelda: Ocarina of Time such a 64DD-based expansion was worked on for a while before being cancelled along with the 64DD. With this Zelda game now decompiled, its source code has shown to be still full of 64DD-related code that [Skawo] takes us through in the video.

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Teardown Of Boeing 777 Cabin Pressure Control System

January 3, 2026 by Maya Posch 24 Comments

Modern passenger airliners are essentially tubes-with-wings, they just happen to be tubes that are stuffed full with fancy electronics. Some of the most important of these are related to keeping the bits of the tube with humans inside it at temperatures and pressures that keeps them alive and happy. Case in point the Boeing 777, of which [Michel] of Le Labo de Michel on YouTube recently obtained the Cabin Pressure Control System (CPCS) for a teardown.

The crucial parts on the system are the two Nord-Micro C0002 piezo resistive pressure transducers, which measure the pressure inside the aircraft. These sensors, one of which is marked as ‘backup’, are read out by multiple ADCs connected to a couple of FPGAs. The system further has an ARINC 429 transceiver, for communicating with the other avionics components. Naturally the multiple PCBs are conformally coated and with vibration-proof interconnects.

Although it may seem like a lot of hardware just to measure air pressure with, this kind of hardware is meant to work without errors over the span of years, meaning significant amounts of redundancy and error checking has to be built-in. Tragic accidents such as Helios Airways Flight 522 involving a 737-300 highlight the importance of these systems. Although in that case human error had disabled the cabin pressurization, it shows just how hard it can be to detect hypoxia before it is too late.

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Benchmarking Windows Against Itself, From Windows XP To Windows 11

January 2, 2026 by Maya Posch 93 Comments

Despite faster CPUs, RAM and storage, today’s Windows experience doesn’t feel noticeably different from back in the 2000s when XP and later Windows 7 ruled the roost. To quantify this feeling, [TrigrZolt] decided to run a series of benchmarks on a range of Windows versions.

Covering Windows XP, Vista, 7, 8.1, 10 and 11, the Pro version of each with the latest service packs and updates was installed on the same laptop: a Lenovo ThinkPad X220. It features an Intel i5 2520M CPU, 8 GB of RAM, built-in Intel HD Graphics 3000 and a 256 GB HDD.

For start-up, Windows 8.1 won the race, probably due to having the Fast Boot feature, while Windows 11 came in dead last as it showed the desktop, but struggled to show the task bar. Windows XP’s install size was the smallest and also had the lowest RAM usage with nothing loaded at 800 MB versus 3.3 GB for Windows 11 in last place.

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