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.

Stealing Joules From An Aluminium-Air Battery

While batteries are cheap and readily obtainable today, sometimes it’s still fun to mess around with their less-common manifestations. Experimenting with a few configurations, Hackaday.io user [will.stevens] has assembled an aluminium-air battery and combined it with a joule thief to light an LED.

To build the air battery, soak an activated charcoal puck — from a water filter, for example — in salt-saturated water while you cut the base off an aluminium can. A circle of tissue paper — also saturated with the salt water — is pressed between the bare charcoal disk and the can, taking care not to rip the paper, and topped off with a penny and a bit of wire. Once clamped together, the reaction is able to power an LED via a simple joule thief.

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GPS Tracker Gets SMS Upgrade

In May of 2000, then-President Bill Clinton signed a directive that would improve the accuracy of GPS for anyone. Before this switch was flipped, this ability was only available to the military. What followed was an onslaught of GPS devices most noticeable in everyday navigation systems. The large amount of new devices on the market also drove the price down to the point where almost anyone can build their own GPS tracking device from scratch.

The GPS tracker that [Vadim] created makes use not just of GPS, but of the GSM network as well. He uses a Neoway M590 GSM module for access to the cellular network and a NEO-6 GPS module. The cell network is used to send SMS messages that detail the location of the unit itself. Everything is controlled with an ATmega328P, and a lithium-ion battery and some capacitors round out the fully integrated build.

[Vadim] goes into great detail about how all of the modules operate, and has step-by-step instructions on their use that go beyond what one would typically find in a mundane datasheet. The pairing of the GSM and GPS modules seems to go match up well together, much like we have seen GPS and APRS pair for a similar purpose: tracking weather balloons.

Open Your Garage Door With Your Smartphone

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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Stealth Cell Tower Inside This Office Printer Calls to Say I Love You

If you look around the street furniture of your city, you may notice some ingenious attempts to disguise cell towers. There are fake trees, lamp posts with bulges, and plenty you won’t even be aware of concealed within commercial signage. The same people who are often the first to complain when they have no signal it seems do not want to be reminded how that signal reaches them. On a more sinister note, government agencies have been known to make use of fake cell towers of a different kind, those which impersonate legitimate towers in order to track and intercept communications.

In investigating the phenomenon of fake cells, [Julian Oliver] has brought together both strands by creating a fake cell tower hidden within an innocuous office printer. It catches the phones it finds within its range, and sends them a series of text messages that appear to be from someone the phone’s owner might know. It then prints out a transcript of the resulting text conversation along with all the identifying information it can harvest from the phone. As a prank it also periodically calls phones connected to it and plays them the Stevie Wonder classic I Just Called To Say I Love You.

In hardware terms the printer has been fitted with a Raspberry Pi 3, a BladeRF software-defined transceiver, and a pair of omnidirectional antennas which are concealed behind the toner cartridge hatch. Software comes via  YateBTS, and [Julian] provides a significant amount of information about its configuration as well as a set of compiled binaries.

In one sense this project is a fun prank, yet on the other hand it demonstrates how accessible the technology now is to impersonate a cell tower and hijack passing phones. We’re afraid to speculate though as to the length of custodial sentence you might receive were you to be caught using one as a private individual.

We’ve considered the Stingray cell phone trackers before here at Hackaday, as well as looking at a couple of possible counter-measures. An app that uses a database of known towers to spot fakes, as well as a solution that relies on an SDR receiver to gather cell tower data from a neighbourhood.

[via Hacker News]

Li-Ion Tech Staring Into the Abyss with Note 7 Failure

Unless you’ve been living under a high voltage transformer, you’ve heard about the potential for Samsung’s latest phone, the Note7, to turn into a little pocket grenade without warning. With over 2.5 million devices in existence, it’s creating quite a headache for the company and its consumers.

They quickly tied the problem to faulty Li-ion batteries and started replacing them, while issuing a firmware update to stop charging at 60 percent capacity. But after 5 of the replacement phones caught fire, Samsung killed the Note7 completely. There is now a Total Recall on all Note7 phones and they are no longer for sale.  If you have one, you are to turn it off immediately. And don’t even think about strapping it into a VR headset — Oculus no longer supports it. If needed, Samsung will even send you a fireproof box and safety gloves to return it.

note_01
Every airline has been broadcasting warnings not to power on or charge a Note 7 on a plane. Image Source: CNET

It should be noted that the problem only affects 0.01% of the phones out there, so they’re not exactly going to set the world on fire. However, it has generated yet another discussion about the safety of Li-ion battery technology.

It was just a few months ago we all heard about those hoverboards that would catch fire. Those questionably-engineered (and poorly-named) toys used Li-ion batteries as well, and they were the source of the fire problem. In the wake of this you would think all companies manufacturing products with Li-ion batteries in them would be extra careful. And Samsung is no upstart in the electronics industry — this should be a solved problem for them.

Why has this happened? What is the deal with Li-ion batteries? Join me after the break to answer these questions.

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Bunnie and Snowden Explore iPhone’s Hackability

[Bunnie Huang] and [Edward Snowden] have teamed up to publish a paper exploring the possibility of introspection on the iPhone.

A rendering of the proposed introspection device attached to an iPhone6
A rendering of the proposed introspection device attached to an iPhone6

The idea is that phones are increasingly complex and potentially vulnerable to all kinds of digital surveillance. Even airplane mode is insufficient for knowing that your phone isn’t somehow transmitting information. The paper looks at the various radios on the iPhone, going so far as opening up the device and reading signals at each of the chips for cell, WiFi, Bluetooth, GPS, and NFC to determine whether the chip itself is doing anything, regardless of what the screen says. This introspection can then be used to be confident that the phone is not communicating when it shouldn’t be.

The paper goes on to propose a device that they will prototype in the coming year which uses an FPC that goes into the phone through the SIM card port. It would contain a battery, display, buttons, multiple SIM cards, and an FPGA to monitor the various buses and chips and report on activity.

Significant hacking of an iPhone will still be required, but the idea is to increase transparency and be certain that your device is only doing what you want it to.