Phone Hacks

175 Articles

Linux Cell Phone? Build OURPhone

May 5, 2023 by 30 Comments

[Evan] couldn’t find a phone he liked, so he decided to build his own. There are advantages and disadvantages, as you might expect. On the plus side, you have the ultimate control. On the negative side, it doesn’t quite have the curb appeal — at least to the average user — of a sleek new cell phone from a major manufacturer.

The phone uses a Raspberry Pi, along with a 4G modem and a 480×800 touchscreen. There’s a laser cut box that measures 90x160x30 mm. For reference, a Google Pixel 7 is about 73x156x9 mm, so a little easier on the pocket.

But not one the pocketbook. The OURPhone only costs about $200 USD to build. There are trade-offs. For example, the touchscreen is resistive, so you’ll want a stylus (there’s a slot for it in the case). On the other hand, if you don’t like something, it is all there for you to change.

Obviously, a better screen would help. Thinner batteries might be a good enhancement too. But that’s the beauty of an open project. You can do all these things and more.

We wondered if you could get one of the “mobile” Linux editions to run or even Android. It seems like the hardest part is coming up with a sophisticated enclosure.

Using An Old Smartphone In Place Of A Raspberry Pi

April 27, 2023 by 62 Comments

The Raspberry Pi was a fairly revolutionary computing device when it came on the scene around a decade ago. Enough processing power to run a full Linux desktop and plenty of GPIO meant almost certain success. In the past year, though, they’ve run into some issues with their chip supplier and it’s been difficult to find new Pis, which has led to some looking for alternatives to these handy devices. [David] was hoping to build a music streaming server and built it on an old smartphone instead of the ubiquitous single-board computer.

Most smartphones are single-board computers though, and at least the Android devices are fully capable of running Linux just like the Pi. The only problem tends to be getting around the carrier or manufacturer restrictions like a locked bootloader or lack of root access. For [David]’s first try getting this to work, he tried to install Navidrome on a Samsung phone but had difficulties with the lack of memory and had to build the software somewhere else and then load it on the phone. It did work, but the stock operating system kept killing the process for consuming too much memory.

Without root access, [David] decided to try LineageOS, a version of Android which, among other benefits, is typically much more configurable than the stock version of Android that is shipped with smartphones. This allowed him to disable or uninstall anything not needed for his music server to free up enough memory. After some issues with transcoding the actual music files he planned on streaming, his music server was successfully up and running on a phone that would have otherwise been relegated to the junk drawer. The specific steps he took to get this working can be found on his GitHub page as well.

[David] also mentioned looking at PostmarketOS for this job which is certainly a viable option for some, but the Linux distribution for phones is only supported on a few devices. Another viable alternative for a project like this if no Raspberry Pis are available might be any of a number of Pine64 devices that might also be sitting around gathering dust, like the versatile Linux-based Pinephone.

Cold War Military Telephones Now Usable Thanks To DIY Switch Build

March 30, 2023 by 17 Comments

The TA-1042 is the most badass looking telephone you’ll ever see. It’s a digital military telephone from the 1980s, but sadly non-functional unless it’s hooked up to the military phone switches it was designed to work with. These days, they’re really only useful as a heavy object to throw at somebody… that is, unless you had the suitable supporting hardware. As it turns out, [Nick] and [Rob] were able to whip up exactly that.

Their project involved implementing the TA-1042’s proprietary switching protocol on a Raspberry Pi Pico. The microcontroller’s unique Programmable I/O subsystem proved perfect for the task. With a little programming and a hat for the Pico to interface with the hardware, they were able to get the TA-1042 working as intended. It involved learning how to encode and decode the Manchester encoded data used by the Digital Non-secure Voice Terminal equipment. Notably, the TA-1042 isn’t the only phone you can use with this setup. You can also hook up other US military DNVT phones, like the TA-954 or TA-1035.

If you want this hardware for yourself, you can simply buy one of [Nick] and [Rob]’s DNVT switches from Tindie. Alternatively, you can roll your own with the source code provided on GitHub.

We’ve seen these phones before repurposed in an altogether different fashion. We’ve also taken a deep dive into the details of the military’s AUTOVON network.

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Glowscope Reduces Microscope Cost By Orders Of Magnitude

March 24, 2023 by 15 Comments

As smartphones become more ubiquitous in society, they are being used in plenty of ways not imaginable even ten or fifteen years ago. Using its sensors to gather LIDAR information, its GPS to get directions, its microphone to instantly translate languages, or even use its WiFi and cellular radios to establish a wireless hotspot are all things which would have taken specialized hardware not more than two decades ago. The latest disruption may be in microscopy, as this build demonstrates a microscope that would otherwise be hundreds of thousands of dollars.

The microscope is a specialized device known as a fluorescence microscope, which uses a light source to excite fluorescent molecules in a sample which can illuminate structures that would otherwise be invisible under a regular microscope. For this build, the light is provided by readily-available LED lighting as well as optical filters typically used in stage lighting, as well as a garden-variety smartphone. With these techniques a microscope can be produced for around $50 USD that has 10 µm resolution.

While these fluorescence microscopes do have some limitations compared to units in the hundred-thousand-dollar range, perhaps unsurprisingly, they are fairly impressive for such a low-cost alternative. More details about these builds can also be found in their research paper published in Nature. Even without the need for fluorescence microscopy, a smartphone has been shown to be a fairly decent optical microscope, provided you have the right hardware to supplement the phone’s camera.

Photo of a smartphone with the ATTiny85 inserted into it, with a screen unlock pattern being drawn on the screen

ATtiny85 Automates Your Smartphone

March 2, 2023 by 14 Comments

It might not seem too impressive these days, but when microcontrollers with hardware USB support were more expensive and rare, the VUSB library was often used to create USB devices with an ATtiny85. It became so popular that the ATtiny85 even got packaged into USB dongle formfactors, like the DigiSpark boards. Well, you might not know this, but your Android smartphones can also work with USB mice and touchscreens in lieu of the built-in touchscreen display. [ErfanSn] combined these two ideas, creating a library to automate smartphone touchscreen events and keyboard input with an ATtiny85 — open for all of us to use, and with examples to spare.

The library is called DigiCombo, and it comes with plenty of examples for any screen touch event emulation that you might want. For instance, check out the README — it has video examples for Instagram page scrolling, unlock screen brute-forcing with random coordinates, playing the Stack rhythm game, and pinch zoom — all the building blocks for your smartphone touch emulation needs are covered pretty well! Of course, all of these have example code corresponding to them, that you can download and base your own ideas on. What’s more, the library is available in current Arduino IDE under the DigiCombo name. So if you need to, say, make a quick autoclicker for your phone, the library is a few steps away!

If your smartphone project was stalled because you needed to emulate touchscreen input, this library is your chance to get it done! We appreciate projects that let us get more from smartphones — there’s a lot of those laying around, they’re pretty functional and self-sufficient devices, so it makes sense that some projects of ours could do with a phone instead of a Raspberry Pi. Some manufacturers let us get a bit more of our phones, but this hasn’t really caught on, which means we have to make do with help of libraries like these. Or, perhaps, you rely on your phone day-to-day, and you’d like to add a touchpad to its back?

Homebrew Telephone Exchange Keeps The Family In Touch, In The House And Beyond

January 14, 2023 by 4 Comments

It doesn’t happen often, but every once in a while we stumble upon someone who has taken obsolete but really cool phone-switching equipment and built a private switched telephone in their garage or basement using it. This private analog phone exchange is not one of those, but it’s still a super cool build that’s probably about as ambitious as getting an old step-by-step or crossbar switch running.

Right up front, we’ll stipulate that there’s absolutely no practical reason to do something like this. And hacker [Jon Petter Skagmo] admits that this is very much a “because I can” project. The idea is to support a bunch of old landline phones distributed around the house, and beyond, in a sort of glorified intercom system. The private exchange is entirely scratch-built, with a PIC32 acting as the heart of the system, performing such tasks as DTMF decoding, generating ring voltage, and even providing a CAN bus interface to his home automation system.

The main board supports five line interface daughterboards, which connect each phone to the switch via an RJ11 jack. The interface does the work of detecting when a phone goes off-hook, and does the actual connection between any two phones. A separate, special interface card provides an auto-patch capability using an RDA1846S RF transceiver module; with it, [Jon Petter] can connect to any phone in the system from a UHF handy-talkie. Check out the video below for more on that — it’s pretty neat!

We just love everything about this overengineered project — it’s clearly a labor of love, and the fit and finish really reflect that. And even though it’s not strictly old school, POTS projects like this always put us in the mood to watch the “Speedy Cutover” video one more time.

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A laptop with a desk phone and a 3D-printed acoustic coupler next to it

Acoustic Coupler Gets You Online Through Any Desk Phone

December 30, 2022 by 47 Comments

Up until the mid-1980s, connecting a computer to a phone line was tricky: many phone companies didn’t allow the connection of unlicensed equipment to their network, and even if they did, you might still find yourself blocked by a lack of standardized connectors. A simple workaround for all this was an acoustic coupler, a device that played your modem’s sounds directly into a phone’s receiver without any electrical connection. Modem speeds were slow anyway, so the limited bandwidth inherent in such a system was not much of a problem.

Nowadays it’s easier to find an internet connection than a phone line in many places, but if you’re stuck in an ancient hotel in the middle of nowhere you might just find [GusGorman]’s modern take on the acoustic coupler useful. The basic design is quite simple: it’s a 3D-printed box with two cups that fit a typical phone handset and a space to put a USB speaker and microphone. Thanks to minimodem it’s easy to set up a connection with any other computer equipped with a phone connection.

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