Building A 3D Printed Phone Handset With Mil-Spec Style

December 28, 2024 by Tom Nardi 14 Comments

In general, military gear is designed to be rugged and reliable. A side effect of this is that the equipment usually has a distinct visual look that many people find appealing. You might not need a laptop that can survive being in a war zone, but plenty of hackers have picked such machines up on the second hand market anyway.

Case in point, the H-250 telephone handset. [Tobias] didn’t actually need a combat-ready phone handset, but loved the way it looked. Technically you can pick these up on eBay for a reasonable price, but then you’ve still got to deal with the weirdo military components inside it. So why not design a look-alike and 3D print it?

[Tobias] came up with a design in OpenSCAD that has a very close resemblance to its military counterpart. Not only has he made the source code for the 3D model available for others who might want to print their own look-alike handset, but the Hackaday.io page also includes a breakdown of the hardware that needs to be added to the printed parts to make it a functional handset.

If you think the H-250 handset looks familiar, it’s probably because it comes standard issue on the TA-1042 field telephone — another very slick looking piece of military gear that we’ve covered previously.

Calling Pink Floyd

December 24, 2024 by Al Williams 38 Comments

[Corelatus] said recently that “someone” asked them to identify the phone signals in the 1982 film The Wall, based on the Pink Floyd song of the same name. We suspect that, like us, that someone might have been more just the hacker part of the brain asserting itself. Regardless, the detective work is fascinating, and you can learn a lot of gory details about phone network in-band signaling from the post.

The analysis is a bit more difficult because of the year the film was made. At that time, different countries used slightly different tone signaling standards. So after generating a spectrogram, the job was to match the tones with known standards to see which one best fit the data.

Continue reading “Calling Pink Floyd” →

An IPhone Case Study

December 15, 2024 by Bryan Cockfield 14 Comments

Way back in 2008, Apple unveiled the first unibody Macbook with a chassis milled out of a single block of aluminum. Before that, essentially all laptops, including those from Apple, were flimsy plastic screwed together haphazardly on various frames. The unibody construction, on the other hand, finally showed that it was possible to make laptops that were both lightweight and sturdy. Apple eventually began producing iPhones with this same design style, and with the right tools and a very accurate set of calipers it’s possible to not only piece together the required hardware to build an iPhone from the ground up but also build a custom chassis for it entirely out of metal as well.

The first part of the project that [Scotty] from [Strange Parts] needed to tackle was actually getting measurements of the internals. Calipers were not getting the entire job done so he used a flatbed scanner to take an image of the case, then milled off a layer and repeated the scan. From there he could start testing out his design. After an uncountable number of prototypes, going back to the CAD model and then back to the mill, he eventually settles into a design but not before breaking an iPhone’s worth of bits along the way. Particularly difficult are the recessed areas inside the phone, but eventually he’s able to get those hollowed out, all the screw holes tapped, and then all the parts needed to get a working iPhone set up inside this case.

[Scotty] has garnered some fame not just for his incredible skills at the precision mill, but by demonstrating in incredible detail how smartphones can be user-serviceable or even built from scratch. They certainly require more finesse than assembling an ATX desktop and can require some more specialized tools, but in the end they’re computers like any other. For the most part.

Continue reading “An IPhone Case Study” →

Smartphone Runs Home Server

December 9, 2024 by Bryan Cockfield 21 Comments

It’s one of the great tragedies of our technological era. Smartphones that feature an incredible amount of computational power compared to computers the past, are largely locked down by carriers or manufacturers, dooming them to performing trivial tasks far below their true capabilities.

But there is hope. In part one of this build, a OnePlus 6T is stripped of its Android operating system in favor of postmarketOS, a Linux distribution based on Alpine designed for a number of Android phones and tablets as well as some Linux-only handhelds. The guide also demonstrates how to remove the battery and use a modified USB-C cable to essentially trick the battery management system into powering up the phone anyway. The second part of the project dives into the software side, getting the Linux system up and running before installing Docker and whichever Docker containers the user needs.

There are a few downsides to running a server from a smartphone. Although there’s plenty of processing power available for a wide range of applications, most phones won’t have Ethernet support out-of-the-box which forces the use of WiFi. There’s also limited storage options available, so a large NAS system may be out of reach. But for something like a home automation system or a music streaming server this could put plenty of older devices to work again. And if you don’t want to hunt for an Android phone that isn’t completely hobbled out-of-the box you might want to try a phone that’s Linux-based from the get-go instead.

Thanks to [JohnU] for the tip!

Dial-up Internet Using The Viking DLE-200B Telephone Line Simulator

November 19, 2024 by Maya Posch 26 Comments

Who doesn’t like dial-up internet? Even if those who survived the dial-up years are happy to be on broadband, and those who are still on dial-up wish that they weren’t, there’s definitely a nostalgic factor to the experience. Yet recreating the experience can be a hassle, with signing up for a dial-up ISP or jumping through many (POTS) hoops to get a dial-up server up and running. An easier way is demonstrated by [Minh Danh] with a Viking DLE-200B telephone line simulator in a recent blog post.

This little device does all the work of making two telephones (or modems) think that they’re communicating via a regular old POTS network. After picking up one of these puppies for a mere $5 at a flea market, [Minh Danh] tested it first with two landline phones to confirm that yes, you can call one phone from the other and hold a conversation. The next step was thus to connect two PCs via their modems, with the other side of the line receiving the ‘call’. In this case a Windows XP system was configured to be the dial-up server, passing through its internet connection via the modem.

With this done, a 33.6 kbps dial-up connection was successfully established on the client Windows XP system, with a blistering 3.8 kB/s download speed. The reason for 33.6 kbps is because the DLE-200B does not support 56K, and according to the manual doesn’t even support higher than 28.8 kbps, so even reaching these speeds was lucky.

Continue reading “Dial-up Internet Using The Viking DLE-200B Telephone Line Simulator” →

World’s First Virtual Meeting: 5,100 Engineers Phoned In

November 16, 2024 by Heidi Ulrich 11 Comments

Would you believe that the first large-scale virtual meeting happened as early as 1916? More than a century before Zoom meetings became just another weekday burden, the American Institute of Electrical Engineers (AIEE) pulled off an unprecedented feat: connecting 5,100 engineers across eight cities through an elaborate telephone network. Intrigued? The IEEE, the successor of the AIEE, just published an article about it.

This epic event stretched telephone lines over 6,500 km, using 150,000 poles and 5,000 switches, linking major hubs like Atlanta, Boston, Chicago, and San Francisco. John J. Carty banged the gavel at 8:30 p.m., kicking off a meeting in which engineers listened in through seat-mounted receivers—no buffering or “Can you hear me?” moments. Even President Woodrow Wilson joined, sending a congratulatory telegram. The meeting featured “breakout sessions” with local guest speakers, and attendees in muted cities like Denver sent telegrams, old-school Zoom chat style.

The event included musical interludes with phonograph recordings of patriotic tunes—imagine today’s hold music, but gloriously vintage. Despite its success, this wonder of early engineering vanished from regular practice until our modern virtual meetings.

We wonder if Isaac Asimov knew about this when he wrote about 3D teleconferencing in 1953. If you find yourself in many virtual meetings, consider a one-way mirror.

Bakelite To The Future – A 1950s Bluetooth Headset

October 31, 2024 by Dave Rowntree 16 Comments

A decade ago, [Jouke Waleson] bought a Dutch ‘model 1950’ PTT (The Dutch Postal Service) rotary-dial telephone of presumably 1950s vintage manufactured by a company called Standard Electric, and decided it would be neat to hack it to function as a Bluetooth hands-free device. Looking at the reverse, however, it is stamped “10.65” on the bottom, so maybe it was made as recently as 1965, but whatever, it’s still pretty old-tech now.

The plan was to utilise ESP32 hardware with the Espressif HFP stack to do all the Bluetooth heavy lifting. [Jouke] did find out the hard way that this is not a commonly-trodden path in hackerland, and working examples and documentation were sparse, but the fine folks from Espressif were on hand via GitHub to give him the help he needed. After ripping into the unit, it was surprisingly stuffed inside there. Obviously, all the switching, even the indication, was purely electromechanical, which should be no surprise. [Jouke] identified all the necessary major components, adding wires and interfacing components as required, but was a bit stumped at the function of one funky-looking component that we reckon must be a multi-tap audio transformer, oddly finished in baby pink! After renovating some interesting cross-shaped mechanical indicators and wiring up some driving transistors, it was time to get on to the audio interface. Continue reading “Bakelite To The Future – A 1950s Bluetooth Headset” →