smartphone

100 Articles

Hackaday Prize Entry: A Femtocell Repeater

May 13, 2017 by 9 Comments

For a Hackaday Prize entry, [TegwynTwmffat] is building a cell phone signal repeater. This sort of device is commercially available, but the options are either expensive or, as with some units available for $30 on DealExtreme, obviously noncompliant with RF regulations. This project intends to create a cost-effective, hackable device that works properly and conforms to the right regulations.

The core of this system is a LimeSDR transceiver. This is a board we’ve seen before, and it has a few interesting features. Basically, the core of the LimeSDR is a programmable RF transceiver with coverage from 100kHz to 3.8GHz. There’s also on-chip signal processing and USB 3.0 bandwidth to get the signals to and from a computer.

Right now, [TegwynTwmffat]’s focus is getting his LimeSDR up and working and figuring out how to set up a few radio blocks to do what is needed. There’s a great update to the project that showcases Pothos, and so far [Tegwyn] has a full-duplex repeater working. This is great work, and really showcases the capabilities of what software-defined radio can do.

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Fundamentals Of Fingerprint Scanning

April 27, 2017 by 28 Comments

Like most (if not all) Hackaday readers, I like to know how the technology I use works. I’m always amazed, for example, how many otherwise smart people have no idea how the cellphone network works other than “it’s a radio.” So now that I have two phones with fingerprint scanners on them, I decided I needed to know more about what’s going on in there.

Sure, I assumed the sensor was capacitive (but maybe not, I found out). Plus we all know some super glue, scotch tape, and gummy bears are all you need to fake one out. However, that’s been known for about 15 years and we are still seeing phones and other devices rolling out with the same scanners. So for now, put aside the debate about whether we should be using fingerprint scanners. Let’s talk about how those sensors work.

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Fix-a-Brick: Fighting The Nexus 5X Bootloop

March 21, 2017 by 124 Comments

Oh Nexus 5X, how could you? I found my beloved device was holding my files hostage having succumbed to the dreaded bootloop. But hey, we’re hackers, right? I’ve got this.

It was a long, quiet Friday afternoon when I noticed my Nexus 5X was asking to install yet another update. Usually I leave these things for a few days before eventually giving in, but at some point I must have accidentally clicked to accept the update. Later that day I found my phone mid-way through the update and figured I’d just wait it out. No dice — an hour later, my phone was off. Powering up led to it repeatedly falling back to the “Google” screen; the dreaded bootloop.

Stages of Grief

I kept my phone on me for the rest of the night’s jubilant activities, playing with it from time to time, but alas, nothing would make it budge. The problem was, my Nexus still had a full day’s video shoot locked away on its internal flash that I needed rather badly. I had to fix the phone, at least long enough to recover my files. This is the story of my attempt to debrick my Nexus 5X.

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Open Your Garage Door With Your Smartphone

January 31, 2017 by 42 Comments

The eternal enemy of [James Puderer]’s pockets is anything that isn’t his smartphone. When the apartment building he resides in added a garage door, the forces of evil gained another ally in the form of a garage door opener. So, he dealt with the insult by rigging up a Raspberry Pi to act as a relay between the opener and his phone.

The crux of the setup is Firebase Cloud Messaging (FCM) — a Google service that allows messages to be sent to devices that generally have dynamic IP addresses, as well as the capacity to send messages upstream, in this case from [Puderer]’s cell phone to his Raspberry Pi. After whipping up an app — functionally a button widget — that sends the command to open the door over FCM, he set up the Pi in a storage locker near the garage door and was able to fish a cable with both ethernet and power to it. A script running on the Pi triggers the garage door opener when it receives the FCM message and — presto — open sesame.

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Stadium Sized Cellphone Light Show Is Controlled By Sound

January 27, 2017 by 35 Comments

18 months ago, [Jameson Rader] didn’t know how to code. He had an economics degree and worked for a minor league hockey team. He did have a dream, though. Broadcasting data through sound. When we say broadcast, we mean broadcast – as in one sender and thousands of receivers.

[Jameson] didn’t have the money to hire a team to build his application. So he did what any self-respecting hacker would do. He bought a few books and taught himself to code. We’re talking about a smartphone app here, so Java and Objective-C were necessary to cover Android and iOS devices. The result is XT Audio Beacons.

[Jameson] has created a light show for stadiums which requires no new hardware infrastructure. Ultrasonic cues are added to a pre-recorded soundtrack and played over the PA system. Fans attending the show simply run an app and hold up their smartphone. The app listens for the cues and turns on the camera flash. The result is a light show which can be synchronized to music, sound effects, or whatever the event calls for. Since the system relies on sound, the App only needs permissions to access the microphone. The system would still work even if the phones were in airplane mode.

Transmitting data to smartphones via ultrasonics isn’t exactly new. Amazon uses it in their Dash Buttons, and Google uses it in their OnHub. Using it as a broadcast medium in a stadium is a novel application, though. [Jameson] also has demos showing XT Audio Beacons being used for more mundane purposes – such as troubleshooting electronics, or even as an acoustic version of an iBeacon.

Most important here is that [Jameson] isn’t keeping all this new knowledge to himself. He’s published the source to his application on Github under the MIT license.

You can see the system in action – and even try it yourself, in the video after the break.

If you want to learn more about [Jameson] and his journey, definitely check out his AMA on Reddit.

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ZeroPhone Gives Smartphones The Raspberry (Pi)

January 18, 2017 by 35 Comments

There are several open source phones out there these days, but all of them have a downside. Hard to obtain parts, hard to solder, or difficult programming systems abound. [Arsenijs] is looking to change all that with ZeroPhone. ZeroPhone is based upon the popular Raspberry Pi Zero. The $5 price tag of the CPU module means that you can build this entire phone for around $50 USD.

The radio module in the ZeroPhone is the well known SIM800L 2G module. 2G is going away or gone in many places, so [Arsenijs] is already researching more modern devices. An ESP8266 serves as the WiFi module with an OLED screen and code in python round out this phone. Sure, it’s not a fancy graphical touchscreen, but a full desktop is just a matter of connecting a display, mouse, and keyboard.

For the security conscious, the ZeroPhone provides a unique level of control. Since this is a Raspberry Pi running Linux, you choose which modules are included in the kernel, and which software is loaded in the filesystem. And with news that we may soon have a blobless Pi, the firmware hiding in the radio modules are the only black boxes still remaining.

If a Raspberry Pi is a bit too much for you to bite off, check out this Arduino based phone. Don’t want to do any soldering? Check out what you can do with a cheap Android phone and a bit of hacking.

Smartphone Case For The Retro Gamer

December 30, 2016 by 8 Comments

A well-designed phone case will protect your phone from everyday bumps with only as much style flair as you’d like. While protection is usually the only real function of a case, some designs — like [Gabbelago]’s Emucase — add specific utility that you might not have known you needed.

Contrary to most cases, the Emucase fits over your phone’s screen, and the resulting facelift emulates the appearance of a Game Boy for easier — you guessed it — Game Boy emulation play on your smartphone.

Cannibalizing a USB SNES gamepad for its buttons and rubber contact pads, Gabbelago then threaded some wire through the contacts, securing it with copper tape and glue; this provides a measurable level of capacitance to register on the touchscreen. Using heat to bend the sides of the 3D printed case so it can attach to the phone is probably the trickiest part of this cool project. Check out his build instructions for any pointers you need.

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