A Complete Exchange From Scratch For Your Rotary Dial Phones

January 29, 2024 by Jenny List 12 Comments

Such has been the success of the mobile phone that in many places they have removed the need for wired connections, for example where this is being written the old copper connection can only be made via an emulated phone line on an internet router. That doesn’t mean that wired phones are no longer of interest to a hardware hacker though, and many of us have at times experimented with these obsolete instruments. At the recent 37C3 event in Germany, [Hans Gelke] gave a talk on the analog exchange he’s created from scratch.

The basic form of the circuit is built around a crosspoint switch array, with interfaces for each line and a Raspberry Pi to control it all. But that simple description doesn’t fully express its awesomeness, rather than hooking up a set of off-the-shelf modules he’s designed everything himself from scratch. His subscriber line interface circuit uses a motor controller to generate the bell signal, his analogue splitter has an op-amp and a transistor, and his crosspoint array is a collection of JFETs. Having dabbled in these matters ourselves, it’s fascinating to see someone else making this work. Video below the break.

Have an analogue phone but nowhere to use it? Bring it to a hacker camp!

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New Robots To Explore New Areas Of Japan’s Fukushima Daiichi Nuclear Plant

January 29, 2024 by Maya Posch 10 Comments

During a press event on January 23rd, Tokyo Electric Power Company (TEPCO) demonstrated two new robots at the mock-up facility at Japan Atomic Energy Agency’s Naraha Center for Remote Control Technology Development (NARREC). As pictured by AP, one is a snake-like robot that should be able to reach very inaccessible areas, while four flying drones will be the first to enter the containment vessel of the Unit 1 reactor for inspection.

These flying drones are 20 cm across, weigh 185 grams each, and were adapted from an existing model that’s used for boiler inspections. At the Naraha Town facility, operators were able to practice flying it into a copy of the Unit 1’s containment vessel via the piping. As the most heavily damaged unit at the Fukushima Daiichi plant, engineers are interested to learn the details of the fuel and debris that has fallen to the bottom of the vessel so that the clean-up and decontamination steps can be planned.

Most of the current work inside the Fukushimi Daiichi reactor buildings is performed by robots, with the TEPCO gallery providing an overview of the wide range of the types used so far.

One of the first was the PackBot, from US-based iRobot, with many more following for a variety of tasks, from inspection to debris clearing and even dry ice-based decontamination.

A Mouse Becomes A Camera

January 29, 2024 by Jenny List 24 Comments

If your pointing device is a mouse, turn it over. The chances are you’ll see a red LED light if you’re not seriously old-school and your mouse has a ball, this light serves as the illumination for a very simple camera sensor. The mouse electronics do their thing by looking for movement in the resulting image, but it should be possible to pull out the data and repurpose the sensor as a digital camera. [Doctor Volt] has a new video showing just that with the innards of a Logitech peripheral.

The mouse contains a microcontroller and the camera part, which fortunately has an SPI interface. The correct register to query the sensor information was deduced, and as if my magic, an image appeared. An M12 lens provided focus with a handy 3D printed mount, and the board went back into the mouse case as a housing. The pictures have something of the Game Boy camera about them, being low-res and monochrome, but it’s still a neat hack.

If you’d like to give it a go you can find the code in a GitHub repository. You might find it worth finding a gaming mouse though, for the much higher resolution sensor.

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3D Printed Axial Compressor Is On A Mission To Inflate Balloons

January 29, 2024 by Donald Papp 5 Comments

[Let’s Print] has been fascinated with creating a 3D printed axial compressor that can do meaningful work, and his latest iteration mixes FDM and SLA printed parts to successfully inflate (and pop) a latex glove, so that’s progress!

Originally, the unit couldn’t manage even that until he modified the number and type of fan blades on the compressor stages. There were other design challenges as well. For example, one regular issue was a coupling between the motor and the rest of the unit breaking repeatedly. At the speeds the compressor runs at, weak points tend to surface fairly quickly. That’s not stopping [Let’s Print], however. He plans to explore other compressor designs in his quest for an effective unit.

Attaching motor shafts to 3D printed devices can be tricky, and in the past we’ve seen a clever solution that is worth keeping in mind: half of a spider coupling (or jaw coupling) can be an economical and effective way to attach 3D printed things to a shaft.

While blowing up a regular party balloon is still asking too much of [Let’s Print]’s compressor as it stands, it certainly inflates (and pops) a latex glove like nobody’s business.

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A Vintage Monitor Lives Again With A New Heart

January 29, 2024 by Jenny List 25 Comments

Aside from keeping decades-old consumer-grade computing hardware working, a major problem for many retrocomputing enthusiasts lies in doing the same for vintage monitors. Whether your screen is a domestic TV or a dedicated monitor, the heat and voltage stress of driving a CRT made these devices significantly less reliable than many of their modern-day counterparts. [Adrian’s Digital Basement] has a worn-out and broken Commodore 1701 monitor, which he’s brought back to life with a modern circuit board and a CRT transplant.

Following on from a previous project, he’s using a replacement board sold as a repair option for CRT TVs on AliExpress. The Commodore monitor has its board on a metal chassis which takes the replacement with a bit of modification. He doesn’t say where the new CRT came from, but we’re guessing it was a late model TV as CRTs made over the last few decades are more interchangeable than might be expected. There’s a moment of mild dodginess as he makes a voltage doubler to run the 220 V board from 120 V with a pair of large electrolytic capacitors hot glued in place, but otherwise it’s a success.

At the end of it all after some testing and set-up he has a Commodore monitor with a new heart and multi-standard support. Is it really a Commodore monitor though, or should it have been repaired? It’s a difficult one to answer, but we’d suggest that CRT monitor repair is less easy today than it used to be because many of the parts are now difficult to find. If it saves at least some of the original from the dumpster it’s better than doing nothing. We wonder how long these upgrades will remain possible as even with Chinese plants making these boards and a handful of CRT TVs still appearing on AliBaba it’s clear that CRTs are at the very end of their life.

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Tech In Plain Sight: Escalators

January 29, 2024 by Al Williams 36 Comments

If you are designing a building and need to move many people up or down, you probably will at least consider an escalator. In fact, if you visit most large airports these days, they even use a similar system to move people without changing their altitude. We aren’t sure why the name “slidewalk” never caught on, but they have a similar mechanism to an escalator. Like most things, we don’t think much about them until they don’t work. But they’ve been around a long time and are great examples of simple technology we use so often that it has become invisible.

Of course, there’s always the elevator. However, the elevator can only service one floor at a time, and everyone else has to wait. Plus, a broken elevator is useless, while a broken escalator is — for most failures — just stairs.

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Need A Serial Data Plotter? Better Write Your Own

January 29, 2024 by Dave Rowntree 12 Comments

When you’re working with a development team, especially in a supporting capacity, you can often find yourself having to invent tools and support systems that are fairly involved, but don’t add to the system’s functionality. Still, without them, it’d be a dead duck. [Aidan Chandra] was clearly in a similar situation, working with a bunch of postgrads at Stanford, on an exoskeleton project, and needed an accurate data plotter to watch measurements in real-time.

This particular problem has been solved many times over, but [Aidan] laments that many solutions available seem to be too complex, hard to extend, or just have broken dependencies. This happens a lot, and it simply leads to yet another project to get going, before you can do the real work it supports. Based on Python and PyQT5, serial-plotter is a new beginning, with an emphasis on correct data acquisition and real-time data visualization with a little processing thrown in. Think, acquire data, show the raw values as well as the mean value, and RMS noise all on the same windows side-by-side, all of which is easily tweakable with a bit of programming using Numpy and Matplotlib.

One particularly important point to highlight is that of the handling of time-stamping. [Aidan] needed to ensure samples were logged together with a local MCU timestamp so that when displayed and possibly later post-processed, it was possible to accurately determine when a particular value or event occurred. With the amount of buffering, data loss and multiple-thread shenanigans, it is easy to forget that the data might get to the application in a non-deterministic way, and just relying on local CPU time is not so useful.

If you need to visualize data transported over the serial port, we have seen many projects to help. Like the highly configurable Serial Studio, for one. If your needs are a bit more complex, especially with multiple data transport methods, then a Supercon 2022 talk by [Alex Whittemore] might be a jolly good place to start.