For a lonely person, elderly or otherwise, the sound of a ringing phone can be music to the ears, unless of course it’s another spam call. But what good is a phone when you can’t hear it well enough to answer?

[Giovanni Aggiustatutto] was tasked with building an additional ringer for a set of cordless landline phones belonging to an elderly friend. Rather than try to intercept the signal, [Giovanni] chose to simply mic up the phone base that’s connected to the phone port on the router and send a signal over Wi-Fi to a second box which has a loud piezo buzzer and a handful of LEDs.

At the heart of this build is a pair of ESP8266 Wemos D1 minis and an Arduino sound sensor module inside a pair of really nice-looking 3D printed boxen that may or may not have been inspired by an IKEA air quality sensor. On the receiving side, a green LED indicates the system is working, and the red LEDs flash as soon as a call comes in.

All the code, schematics, and STL files are available for this build, and between the Instructable and the build video after the break, you should have no trouble replicating it for the hard-of-hearing in your life.

Historically, there have been a few cases of useful wireless power transmission over great distances, like a team at MIT that was able to light up a 60 W bulb at several meters, and of course Nikola Tesla had grand dreams of drawing energy from the atmosphere. But for most of us wireless power is limited to small, short-range devices like cellphone chargers. While it’s not a lot of work to plug in a phone when it needs a charge, even this small task can be automated.

This build begins with a 3D printed cradle for the smartphone to sit in. When the device detects that the phone has been placed in the cradle, it uses a linear actuator to drive a custom-built charging cable into the phone’s USB port. Similarly, when the phone is lifted from the cradle the cable is automatically removed. It appears that there is some play in the phone’s position that lets the charger be plugged in smoothly, and the project’s creator [Larpushka] points out that the linear actuator is not particularly strong so we don’t imagine the risk of damage is very high.

While wireless charging still may have the edge when it comes to keeping debris out of the port, we still really enjoy a project like this that seems to be done for its own sake. There are some improvements that [Larpushka] plans to make, but for now we’re delighted by this build. For anyone looking to add true wireless charging to any phone that doesn’t have it, though, it’s not too difficult to accomplish either.

Purposely choosing obsoleted technology combines all the joy of simpler times with the comfort of knowing you’re not actually stuck with outdated (and oftentimes inferior) technology. The rotary phone is a great example here, and while rarely anyone would want to go back to the lenghty, error-prone way of dialing a number on it on an everyday basis, it can definitely add a certain charm to a project. [Caroline Buttet] thought so as well, and turned her grandma’s old rotary phone into a time-traveling, globe-trotting web radio.

The main idea is fairly simple: a Raspberry Pi connects via browser to a web radio site that plays music throughout the decades from places all over the world. [Caroline]’s implementation has a few nice twists added though. First of all, the phone of course, which doesn’t only house the Raspberry Pi, but serves both as actual listening device via handset speaker, and as input device to select the decade with the rotary dial. For a headless setup, she wrote a Chromium extension that maps key events to virtual clicks on the corresponding DOM element of the web site — like the ones that change the decade — and a Python script that turns the rotary dial pulses into those key events.

However, the phone is only half the story here, and the country selection is just as fascinating — which involves an actual world map. An audio connector is attached to each selectable country and connected to an Arduino. If the matching jack is plugged into it, the Arduino informs the Raspberry Pi via serial line about the new selection, and the same Chromium extension then triggers the country change in the underlying web site. You can check all the code in the project’s GitHub repository, and watch a demo and brief explanation in the videos after the break.

Sure, listening radio through a telephone may not be the most convenient way — unless it’s the appropriate genre — but that clearly wasn’t the goal here anyway. It’s definitely an interesting concept, and we could easily see it transferred to some travel- or spy-themed escape room setting. And speaking of spying, if [Caroline]’s name sounds familiar to you, you may remember her virtual peephole from a few months back.

Imagine for a moment that you’ve been tasked with developing a device for interfacing with a global network of interconnected devices. Would you purposely design a spring-loaded dial that can do nothing but switch a single set of contacts on and off from 1 to 10 times? What kind of crazy world would we have to live in where something like that was the pinnacle of technology?

Obviously, such a world once existed, and now that we’ve rolled the calendar ahead a half-century or so, both our networks and our interfaces have gotten more complex, if arguably better. But [Jan Derogee] thinks a step backward is on order, and so he built this rotary phone web browser. The idea is simple: pick up the handset and dial the IP address of the server you want to connect to. DNS? Bah, who needs it?

Of course there is the teensy issue that most websites can’t be directly accessed via IP address anymore, but fear not – [Jan] has an incredibly obfuscated solution to that. It relies on the fact that many numbers sound like common phrases when sounded out in Chinese, so there end up being a lot of websites that have number-based URLs. He provides an example using the number 517, which sounds a bit like “I want to eat,” to access the Chinese website of McDonald’s. How the number seven sounding like both “eat” and “wife” is resolved is left as an exercise to the reader.

And here we thought [Jan]’s rotary number pad was of questionable value. Still, we appreciate this build, and putting old phones back into service in any capacity is always appreciated.

Music, food, and coding style have one thing in common: we all have our own preferences. On the other hand, there are arguably more people on this planet than there are varieties in any one of those categories, so we rarely fail to find like-minded folks sharing at least some of our taste. Well, in case your idea of a good time is calling a service hotline for some exquisite tunes, [Fuzzy Wobble] and his hold music jukebox, appropriately built into a telephone, is just your guy.

Built around an Arduino with an Adafruit Music Maker shield, [Fuzzy Wobble] uses the telephone’s keypad as input for selecting one of the predefined songs to play, and replaced the phone’s bell with a little speaker to turn it into a jukebox. For a more genuine experience, the audio is of course also routed to the handset, although the true hold music connoisseur might feel disappointed about the wide frequency range and lack of distortion the MP3s used in his example provide. Jokes aside, projects like these are a great reminder that often times, the journey really is the reward, and the end result doesn’t necessarily have to make sense for anyone to enjoy what you’re doing.

As these old-fashioned phones gradually disappear from our lives, and even the whole concept of landline telephony is virtually extinct in some parts of the world already, we can expect to see more and more new purposes for them. Case in point, this scavenger hunt puzzle solving device, or the rotary phone turned virtual assistant.

The invention of the transistor ushered in a lot of technologies that we now take for granted, and one of the less-thought-about areas that it improved living conditions worldwide was by making the touch-tone phone possible. No longer would the world have to fuss with dials to make phone calls, they could simply push some buttons. This technology is still in use today, and it is possible to build external phone dialers that use these tones to make phone calls, as [SunFounder] demonstrates with his latest project.

The tones that a phone makes when a button is pressed correlate with specific frequencies for each number. Automatic dialers like this one help when there are multiple carriers (like different long-distance carriers, for example) where different prefixes can be used to make calls cheaper depending on the destination of the call. A preprogrammed dialer can take all of this complication out of making phone calls. [SunFounder] is able to make a simple dialer from scratch, using an Arduino, its “tone” library, and a speaker that is simply held up to the phone that the call will be placed on.

[SunFounder] points out that he built this more because he’s interested in the inner workings of phones, and not because he needed a purpose-built dialer. It’s a good demonstration of how phones continue to use DTMF though, and how easy it is to interface with such a system. It might also suit a beginner as an introduction to the world of phreaking.

Due largely to the overwhelming dominance of mobile phones, payphones are a sometimes overlooked relic from the 90’s and earlier eras. While seldom seen out in the wild these days, they can however still be acquired for a moderate fee — how many of you knew that? Setting out to prove the lasting usefulness of the payphone, Instructables user [Fuzzy-Wobble] has dialed the retro spirit way past eleven to his ’90 from the ’90s’ payphone boombox.

Conspicuously mounted in the corner of his office, a rangefinder sets the phone to ringing when somebody walks by — a fantastic trap for luring the curious into a nostalgia trip. Anyone who picks up will be prompted to punch in a code from the attached mini-phone book and those who do will be treated to one of ninety hits from — well —  the 1990’s. All of the songs have been specifically downgraded to 128kbps for that authentic 90’s sound — complete with audio artifacts. There’s even a little easter egg wherein hitting the coin-return lever triggers the payphone to shout “Get a job!”

[Fuzzy-Wobble] notes that a payphone bracket is indispensable as most all payphones are made of cast iron, and nobody likes holes ripped out of their walls due to improper mounting. They’ve also provided their code as well as links to other tutorials for aspects of the build — such as the Adafruit music maker — throughout. Now you’ll have to excuse us as we groove while lost in a reverie.

Kick it back an extra decade and you get an 80’s boombox bluetooth speaker.

[Thanks for the submission, Alex S!!]

Payphones used to be found on just about every street corner. They were a convenience, now replaced by the ubiquitous mobile phone. These machines were the stomping grounds for many early computer hackers, and as a result hold a place in hacker history. If you’ve ever wanted to re-live the good ol’ days, [hharte’s] project might be for you.

[hharte] has been working to make these old payphones useful again with some custom hardware and software. The project intends to be an interface between a payphone and an Asterisk PBX system. On the hardware side, the controller board is capable of switching various high voltage signals required for coin-line signaling. The controller uses a Teensy microcontroller to detect the hook status as well as to control the relays. The current firmware features are very basic, but functional.

[hharte] also wrote a custom AGI script for Asterisk. This script allows Asterisk to detect the 1700hz and 2200hz tones transmitted when coins are placed into the machine. The script is also in an early stage, but it will prompt for money and then place the call once 25 cents has been deposited. All of the schematics and code can be found on the project’s github page.

[Thanks mies]