GGWave Sings The Songs Of Your Data

July 6, 2022 by Elliot Williams 12 Comments

We’re suckers for alternative data transmission methods, and [Georgi Gerganov]’s ggwave made us smile. At its core, it’s doing what the phone modems of old used to do – sending data encoded as different audio tones. But GGwave does this with sophistication!

It splits the data into four-bit chunks, and uses 16 different frequency offsets to represent each possible value. But for each chunk, these offsets are added to one of six different base frequencies, which allows the receiving computer to tell which chunk it’s in. It’s like a simple framing concept, and it makes the resulting data sound charmingly like R2-D2. (It also uses begin and end markers to be double-sure of the framing.) The data is also sent with error correction, so small hiccups can get repaired automatically.

What really makes ggwave shine is that it’s ported to every platform you care about: ESP32, Arduino, Linux, Mac, Windows, Android, iOS, and anything that’ll run Python or JavaScript. So it’ll run in a browser. There’s even a GUI for playing around with alternative modulation schemes. Pshwew! This makes it easy for a minimalist microcontroller-based beeper button to control your desktop, or vice-versa. An ESP32 makes for an IoT-style WiFi-to-audio bridge. Write code on your cell phone, and you can broadcast it to any listening microcontroller. Whatever your use case, it’s probably covered.

Now the downside. The data rate is slow, around 64-160 bits per second, and the transmission is necessarily beepy-booopy, unless you pitch it up in to the ultrasound or use the radio-frequency HackRF demo. But maybe you want to hear when your devices are talking to each other? Or maybe you just think it’s cute? We do, but we wouldn’t want to have to transmit megabytes this way. But for a simple notification, a few bytes of data, a URL, or some configuration parameters, we can see this being a great software addition to any device that has a speaker and/or microphone.

Oh my god, check out this link from pre-history: a bootloader for the Arduino that runs on the line-in.

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How A Smartphone Is Made, In Eight “Easy” Blocks

May 9, 2022 by Matthew Carlson 21 Comments

The smartphone represents one of the most significant shifts in our world. In less than thirteen years, we went from some people owning a dumb phone to the majority of the planet having a smartphone (~83.7% as of 2022, according to Statista). There are very few things that a larger percentage of people on this planet have. Not clean water, not housing, not even food.

How does a smartphone work? Most people have no idea; they are insanely complicated devices. However, you can break them down into eight submodules, each of which is merely complex. What makes them work is that each of these components can be made small, at massive economies of scale, and are tightly integrated, allowing easy assembly.

So without further ado, the fundamental eight building blocks of the modern cellphone are: the application processor, the baseband processor, a SIM card, the RF processor, sensors, a display, cameras & lenses, and power management. Let’s have a look at them all, and how they fit together.

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Monitor Space Weather And The Atmosphere With Your Cellphone!

April 4, 2022 by Jenny List 9 Comments

Above our heads, the atmosphere is a complex and unpredictable soup of gasses and charged particles subject to the influence of whatever the Sun throws at it. Attempting to understand it is not for the faint-hearted, so it has for centuries been the object of considerable research. A new project from the European Space Agency and ETH Zurich gives the general public the chance to participate in that research in a small way, by crowdsourcing atmospheric data gathering to a mobile phone app. How might a mobile phone observe the atmosphere? The answer lies in their global positioning receivers, which can track minute differences in the received signals caused by atmospheric conditions. By gathering as much of this data as possible, the ESA scientists will gain valuable insights into atmospheric conditions as they change across the globe.

The app requires an Android phone equipped with a dual frequency satnav receiver, and having been duly installed on the trusty Hackaday Motorola it in turn started picking up all the different constellations of satellites. The instructions are to leave it somewhere such as a windowsill with an unobstructed view of the sky and move it as little as possible, to which we’d add clicking the “Log in background” button and connectign a charger. There’s a promise that uploaders can win prizes, so aside from contributing to scientific discovery there might be an unexpected benefit. More details on the app can be found here, meanwhile many readers will know that this isn’t the only crowdsourced atmospheric data gathering effort.

Replaceable Batteries Are Coming Back To Phones If The EU Gets Its Way

March 30, 2022 by Lewin Day 150 Comments

Back in the day, just about everything that used a battery had a hatch or a hutch that you could open to pull it out and replace it if need be. Whether it was a radio, a cordless phone, or a cellphone, it was a cinch to swap out a battery.

These days, many devices hide their batteries, deep beneath tamper-proof stickers and warnings that state there are “no user serviceable components inside.” The EU wants to change all that, though, and has voted to mandate that everything from cellphones to e-bikes must have easily replaceable batteries, with the legislation coming into effect as soon as 2024.

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Here’s How Those Battery-Free Flashing Phone Stickers Worked

February 26, 2022 by Lewin Day 27 Comments

The late 90s and early 2000s were a breakout time for mobile phones, with cheap GSM handsets ushering in the era in which pretty much everybody had a phone. Back then, a popular way to customize one’s phone was to install a sticker that would flash when the phone rang. These required no batteries or any other connection to the phone, and [Big Clive] has dived in to explain how they worked.

The simple schematic of the flashing sticker circuit. The flashing was generated by the pulses of RF energy from the smartphone.

It’s an old-fashioned teardown that requires a bit of cutting to get inside the sticker itself. A typical example had three LEDs in series for a total voltage drop of around 7V, hooked up to two diodes and a PCB trace antenna. A later evolution used raw unpackaged components bonded to the PCB. Future versions went down to a single diode, using the LEDs to serve as the second. The basic theory was that the PCB traces would pick up RF transmitted by the phone when a call was coming in, lighting the LEDs.

In the 2G era, the freuqencies used were on the order of 300 MHz to 1.9GHz. A combination of the change in frequencies used by modern phone technology and the lower transmit powers used by handsets means that the stickers don’t work properly with modern phones according to [Big Clive].

Incidentally, you might like to consider running your own old-school cellphone network. Video after the break.

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Finally, A Use For Old Cellphones

December 4, 2021 by Elliot Williams 50 Comments

In what is now a three-year long search, I’ve finally found the perfect use for an old cellphone. And with it, the answer to a burning question: Why aren’t we hacking cellphones?

First, the application. The Octo4a project lets you use an old Android phone as a 3D printer server, web interface, and even time-lapse camera to make those nice movies where the print seems to grow up out of nothing before your eyes. It’s the perfect application for an old phone, making use of the memory, WiFi, graphics capabilities, and even the touch-screen if you want local control of your prints.

Connecting to the phone was the main hurdle that I’ve always seen in developing for cellphone projects, because I have robotics applications in mind. But Octo4a gets around this with low or no effort. Most 3D printers are designed to run on USB anyway, so connecting it to the phone is as simple as buying a USB OTG cable. With the USB port taken over, powering the phone long-run becomes a tiny problem, which can be solved with a Y-cable or a little solder. Keep the OS from going to sleep, somehow, and it’s problem solved!

But here’s why this isn’t a solution, and it points out the deeper problem with cellphone hacking that many pointed out in the comments three years ago. Octoprint is written in Python, and because of this is very easy to write extensions for and to hack on, if that’s your thing. When I first saw Octo4a, I thought “oh great, a working Android Python port”. Then I went to dig into the code.

Octo4a is written in Kotlin and uses the Gradle framework. It’s a complete port of Octoprint, not just to a different platform, but to a different programming language and to an almost entirely different programming paradigm. My hat is off to [feelfreelinux] for doing it, but my guess is that the community of other people fluent enough in Kotlin and Python to help port across upstream changes in Octoprint is a lot smaller than the community of Python programmers would have been. Octo4a is a great project, but it’s not a walk in the park to develop on it.

So all of you who wrote in the comments to my previous piece that it’s the Android software ecosystem that’s preventing phone reuse, well here’s the exception that proves your rule! A dedicated and talented, multi-lingual developer community could pull it off, but the hurdle is so high that few will rise to it.

Anyway, thanks [Feelfree Filip] for your great work! I’ll be putting this on my old S4.

A Phone That Old Shouldn’t Be Running Android

June 28, 2021 by Jenny List 23 Comments

Cars and smartphones have something curious in common, just as most everyday saloon cars from different manufacturers have tended towards similarity, so have smartphones. Whether your smartphone the latest and greatest or only cost you $50 from a supermarket, it matters little to look at because both phones will be superficially near-identical black slabs.

It wasn’t always this way though, in decades past phones from different manufacturers each had their own flavours, and there was a variety in form factors to suit all tastes. There’s a ray of hope for fans of those days though, in the form of [befinitiv]’s 2000-era Sony flip phone. It runs Android. Yes, you read that right, there on the tiny screen is Android 9.

Of course whatever processor and electronics the phone came with are long gone, and instead the phone sports the internals of a modern Chinese watch-smartphone grafted in in place of the original. The whole electronics package fits in the screen opening, and though it required some wiring for the USB-C socket and a few other parts it looks for all the world from the outside as though it was meant to run Android. You can take a look in the video below the break.

He cheerfully admits that there’s still a way to go for example in getting the original keyboard working, but even with a tiny touchscreen it’s good enough to be a daily driver. It may be a little on the small side, but for those of us who miss our old phones maybe there’s hope in it for something new.

Meanwhile this isn’t the first re-use of an old phone we’ve seen recently.

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