Retro Wall Phone Becomes A Doorbell, And So Much More

We have to admit that this retasked retro phone wins on style points alone. The fact that it’s filled with so much functionality is icing on the cake.

The way [SuperKris] describes his build sounds like a classic case of feature creep. Version 1 was to be a simple doorbell, but [SuperKris] would soon learn that one does not simply replace an existing bell with a phone and get results. He did some research and found that the ringer inside the bakelite beauty needs much more voltage than the standard doorbell transformer supplies, so he designed a little H-bridge circuit to drive the solenoids. A few rounds of “while I’m at it” later, the phone was stuffed with electronics, including an Arduino and an NFR24 radio module that lets it connect to Domoticz, a home automation system. The phone’s rotary dial can now control up to 10 events and respond to alarms and alerts with different ring patterns. And, oh yes – it’s a doorbell too.

In general, we prefer to see old equipment restored rather than gutted and filled with new electronics. But we can certainly get behind any effort to retask old phones with no real place in modern telecommunications. We’ve seen a few of these before, like this desk telephone that can make cell calls.

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The E-Waste Apocalypse Looms

What does post-apocalyptic technology look like? Well, that kind of depends on the apocalypse. Regardless of the cause, we’ll need to be clever and resourceful and re-learn ancient crafts like weaving and pottery-making. After all, the only real apocalyptic constants are the needs of the survivors. Humans need clothing and other textiles. Fortunately, weaving doesn’t require electricity—just simple mechanics, patience, and craftsmanship.

If it turns out the apocalypse is scheduled for tomorrow, we’ll have piles and piles of e-waste as fodder for new-old looms. This adorable loom is a mashup of old and new technologies that [Kati Hyyppä] built at an artist residency in Latvia, a country with a rich historical tapestry of textile-making. It combines a cheerful orange telephone with an old cassette player and some telescoping rods from a radio antenna. [Kati] reused the phone’s hang-up switch to trigger tunes from a deconstructed toddler toy every time the receiver is lifted. Check it out after the beep break.

And yeah, you’re right, it does use batteries. But the looming part doesn’t require power, only the music. In case of apocalypse, just scrounge up a solar panel.

If you’d rather be prepared to have to make your own clothes someday, print this loom beforehand.

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The VU Meter And How It Got That Way

Given its appearance in one form or another in all but the cheapest audio gear produced in the last 70 years or so, you’d be forgiven for thinking that the ubiquitous VU meter is just one of those electronic add-ons that’s more a result of marketing than engineering. After all, the seemingly arbitrary scale and the vague “volume units” label makes it seem like something a manufacturer would slap on a device just to make it look good. And while that no doubt happens, it turns out that the concept of a VU meter and its execution has some serious engineering behind that belies the really simple question it seeks to answer: How loud is this audio signal?

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Hotline Helps Toddler Keep In Touch With Mom And Dad

Even though the age for first carrying a smartphone seems to be decreasing, there’s a practical lower minimum age at which a kid can reliably use one to make a call. So how do you make sure your tot can reach out and touch mommy or daddy? This toddler-friendly Raspberry Pi hotline is a good start.

With a long trip to Hawaii pending and a toddler staying behind, [kuhnto] wanted a way to make communication as simple as possible. In the days of pervasive landlines, that would have been as simple as a feature phone with a couple of numbers on speed dial buttons. With nothing but cell phones to rely on, [kuhnto] turned to a Raspberry Pi running PBX software and a command line SIP client for making calls over a Google Voice line. The user interface is as simple as can be – a handset and two lighted buttons on a wall-mounted box. All Junior needs to do is pick up the handset and push green to talk to Daddy, blue for Mommy. Something similar might even be useful for elder care.

Kudos to [kuhnto] for thinking through the interface issues to come up with a successful build. We’ve seen other UIs simplified for kids before, such as this button-free jukebox or this special-needs media player.

[via r/DIY]

Emergency Cell Tower On A Budget

Cell phone towers are something we miss when we’re out of range, but imagine how we’d miss them if they had been destroyed by disastrous weather. In such emergencies it is more important than ever to call loved ones, and tell them we’re safe. [Matthew May] and [Brendan Harlow] aimed to make their own secure and open-source cellular network antenna for those occasions. It currently supports calling between connected phones, text messaging, and if the base station has a hard-wired internet connection, users can get online.

This was a senior project for a security class, and it seems that the bulk of their work was in following the best practices set by the Center for Internet Security. They adopted a model intended for the Debian 8 operating system which wasn’t a perfect fit. According to Motherboard their work scored an A+, and we agree with the professors on this one.

Last year, the same SDR board, the bladeRF, was featured in a GSM tower hack with a more sinister edge, and of course Hackaday is rife with SDR projects.

Thank you [Alfredo Garza] for the tip.

Rotary Phones And The Birth Of A Network

I can’t help but wonder how long it will be before the movie title  “Dial M for Murder” becomes mysterious to most of the population. After all, who has seen a dial phone lately? Sure, there are a few retro phones, but they aren’t in widespread use. It may not be murder, but it turns out that the dial telephone has its roots in death — or at least the business of death. But to understand why that’s true, you need to go back to the early days of the telephone.

Did you ever make a tin can phone with a string when you were a kid? That dates back to at least 1667. Prior to the invention of what we think of as the telephone, these acoustic phones were actually used for specialized purposes.

We all know that [Alexander Graham Bell] made a working telephone over a wire, drawing inspiration from the telegraph system. However, there’s a lot of dispute and many others about the same time were working on similar devices. It is probably more accurate to say that [Bell] was the first to successfully patent the telephone (in 1876, to be exact).

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Horns Across America: The AT&T Long Lines Network

A bewildering amount of engineering was thrown at the various challenges presented to the United States by the end of World War II and the beginning of the Cold War. From the Interstate Highway System to the population shift from cities to suburbs, infrastructure of all types was being constructed at a rapid pace, fueled by reasonable assessments of extant and future threats seasoned with a dash of paranoia, and funded by bulging federal coffers due to post-war prosperity and booming populations. No project seemed too big, and each pushed the bleeding edge of technology at the time.

Some of these critical infrastructure projects have gone the way of the dodo, supplanted by newer technologies that rendered them obsolete. Relics of these projects still dot the American landscape today, and are easy to find if you know where to look. One that always fascinated me was the network of microwave radio relay stations that once stitched the country together. From mountaintop to mountaintop, they stand silent and largely unattended, but they once buzzed with the business of a nation. Here’s how they came to be, and how they eventually made themselves relics.

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