Basics Of Remote Cellular Access: Connecting Via VPN

You’ve got a machine hooked up to the Internet via a shiny new cellular modem, which you plan to administer remotely. You do a quick check on the external IP, and try and log in from another PC. Try as you might, SSH simply won’t connect. What gives?

The reality of the modern internet is that most clients no longer get their own unique IPv4 address. There simply aren’t enough to go around anymore. Instead, most telecommunications operators use Carrier Grade Network Address Translation which allows a single external address to be shared by many customers. This can get in the way of direct connection attempts from the outside world. Even if that’s not the case, most cellular operators tend to block inbound connections by default. However, there is a way around this quandary – using a VPN. Continue reading “Basics Of Remote Cellular Access: Connecting Via VPN”

The Challenges Of Monitoring Water Streams And Surviving Mother Nature

Small waterways give life in the form of drinking and irrigation water, but can also be very destructive when flooding occurs. In the US, monitoring of these waterways is done by mainly by the USGS, with accurate but expensive monitoring stations. This means that there is a limit to how many monitoring stations can be deployed. In an effort to come up with a more cost-efficient monitoring solution, [Rohan Menon] and [Ian Vernooy] created Aquametric, a simple water level, temperature and conductivity measuring station.

The device is built around a Particle Electron that features a STM32 microcontroller and a 3G modem. An automotive ultrasonic sensors measures water level, a thermistor measures temperature and a pair of parallel aluminum plates are used to measure conductivity. All the data from the prototype is output to a live dashboard. The biggest challenges for the system came with field deployment.

The great outdoors can be rather merciless with our ideas and electronic devices. [Rohan] and [Ian] did some tests with LoRa, but quickly found that the terrain severely limited the effective range. Power was another challenge, first testing with a solar panel and lithium battery. This proved unreliable especially at temperatures near freezing, so they decided to use 18 AA batteries instead and optimized power usage.

The mounting system is still an ongoing challenge. A metal pole driven into the riverbed at a wider part ended up bent (probably from ice sheets) and covered in debris to the point that it affected water level readings. They then moved to a narrower and shallower section in the hopes of avoiding debris, but the rocky bottom prevented them from effectively driving in a pole. So the mounted the pole on a steel plate which was then packet with rock to keep it in place. This too failed when it tipped over from rising water levels, submerging the entire sensor unit. Surprisingly it survived with only a little moisture getting inside.

For the 2020 Hackaday Prize, Field Ready and Conservation X Labs have issued challenges that need require some careful consideration and testing to build things that can survive the real world. So go forth and hack!

Bike Lock Secures Car

[Buttim] loses his car a lot, which might sound a little bit like the plot from an early-00s movie, but he assures us that it’s a common enough thing. In a big city, and after several days of not driving one’s car, it can be possible to at least forget where you parked. There are a lot of ways of solving this problem, but the solution almost fell right into his lap: repurposing a lock from a bike share bicycle. (The build is in three parts: Part 2 and Part 3.)

These locks are loaded with features, like GPS, a cellular modem, accelerometers, and in this case, an ARM processor. It took a huge amount of work for [Buttim] to get anything to work on the device, but after using a vulnerability to dump the firmware and load his own code on the device, spending an enormous amount of time trying to figure out where all the circuit traces went through layers of insulation intended to harden the lock from humidity, and building his own Python-based programmer for it, he has basically free reign over the device.

To that end, once he figured out how it all worked, he put it to use in his car. The device functions as a GPS tracker and reports its location over the cellular network so it can’t become lost again. As a bonus, he was able to use the accelerometers to alert him if his car was moving without him knowing, so it turned into a theft deterrent as well. Besides that, though, his ability to get into the device’s firmware reminded us of a recent attempt to get access to an ARM platform.

5G Is For Robots

Ecclesiastes 1:9 reads “What has been will be again, what has done will be done again; there is nothing new under the sun.” Or in other words, 5G is mostly marketing nonsense; like 4G, 3G, and 2G was before it. Let’s not forget LTE, 4G LTE, Advance 4G, and Edge.

Just a normal everyday antenna array in a Seattle parking garage.

Technically, 5G means that providers could, if they wanted to, install some EHF antennas; the same kind we’ve been using forever to do point to point microwave internet in cities. These frequencies are too lazy to pass through a wall, so we’d have to install these antennas in a grid at ground level. The promised result is that we’ll all get slightly lower latency tiered internet connections that won’t live up to the hype at all. From a customer perspective, about the only thing it will do is let us hit the 8Gb ceiling twice as faster on our “unlimited” plans before they throttle us. It might be nice on a laptop, but it would be a historically ridiculous assumption that Verizon is going to let us tether devices to their shiny new network without charging us a million Yen for the privilege.

So, what’s the deal? From a practical standpoint we’ve already maxed out what a phone needs. For example, here’s a dirty secret of the phone world: you can’t tell the difference between 1080p and 720p video on a tiny screen. I know of more than one company where the 1080p on their app really means 640 or 720 displayed on the device and 1080p is recorded on the cloud somewhere for download. Not a single user has noticed or complained. Oh, maybe if you’re looking hard you can feel that one picture is sharper than the other, but past that what are you doing? Likewise, what’s the point of 60fps 8k video on a phone? Or even a laptop for that matter?

Are we really going to max out a mobile webpage? Since our device’s ability to present information exceeds our ability to process it, is there a theoretical maximum to the size of an app? Even if we had Gbit internet to every phone in the world, from a user standpoint it would be a marginal improvement at best. Unless you’re a professional mobile game player (is that a thing yet?) latency is meaningless to you. The buffer buffs the experience until it shines.

So why should we care about billion dollar corporations racing to have the best network for sending low resolution advertising gifs to our disctracto cubes? Because 5G is for robots.

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Jeremy Hong: Weaponizing The Radio Spectrum

Jeremy Hong knows a secret or two about things you shouldn’t do with radio frequency (RF), but he’s not sharing.

That seems an odd foundation upon which to build one’s 2018 Hackaday Superconference talk, but it’s for good reason. Jeremy knows how to do things like build GPS and radar jammers, which are federal crimes. Even he hasn’t put his knowledge to practical use, having built only devices that never actually emitted any RF.

So what does one talk about when circumspection is the order of the day? As it turns out, quite a lot. Jeremy focused on how the military leverages the power of radio frequency jamming to turn the tables on enemies, and how civilian police forces are fielding electronic countermeasures as well. It’s interesting stuff, and Jeremy proved to be an engaging guide on a whirlwind tour into the world of electronic warfare.
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Creating A 3G Raspberry Pi Smartphone

It’s hard to believe, but the Raspberry Pi has now been around long enough that some of the earliest Pi projects could nearly be considered bonafide vintage hacks at this point. A perfect example are some of the DIY Raspberry Pi smartphone projects that sprung up a few years back. Few of them were terribly practical to begin with, but even if you ignore the performance issues and bulkiness, the bigger problem is they relied on software and cellular hardware that simply isn’t going to cut it today.

Which was exactly the problem [Dylan Radcliffe] ran into when he wanted to create his own Pi smartphone. There was prior art to use as a guide, but the ones he found were limited to 2G cellular networks which no longer exist in his corner of the globe. He’s now taken on the quest to develop his own 3G-capable Pi smartphone, and his early results are looking very promising.

Inside the phone, which he calls the rCrumbl, [Dylan] has crammed a considerable amount of hardware. A Raspberry Pi 3B+ with attached Adafruit touchscreen LCD is the star of the show, but there’s also a Pi camera module, battery charging circuit, and Adafruit FONA 3G modem (which also provides GPS). Powering the device is a 2500 mAh 3.7V battery, which reportedly delivers a respectable 8 to 12 hour runtime.

The case is 3D printed, and [Dylan] says it took a long time to nail down a design that would fit all of his hardware, keep things from shifting around, and still be reasonably slim. Obviously DIY phones like this are never going to be as slim as even the chunkiest of modern smartphones, but the rCrumbl looks fairly reasonable for a portable device. We especially like the row of physical buttons he’s included along the bottom of the screen, which should help with the device’s usability.

Speaking of usability, that’s where [Dylan] still has his work cut out for him. The existing software he’s found won’t work on 3G, so he’s going to have to come up with his own software stack to provide a proper phone interface. As it stands he’s made a call on the rCrumbl using command line tools, but while that might score you some extra geek points at the next hacker meetup, it’s not exactly going to fly for daily use. He mentions he would love to talk to any developers out there that would like to team up on the software side of the project.

We’ve covered one of the 2G Pi smartphones in the past, and of course the ZeroPhone is a very interesting project if you don’t mind the “dumb phone” interface. But if you’re looking for something that’s fairly close to commercial devices in terms of usability, you might just want to roll your own Android phone.

GSM Phone Network At EMF Camp Built On Raspberry Pi And LimeSDR

The Electromagnetic Field 2018 hacker camp in the UK will have its own GSM phone network, and as we have already covered its badge will be a fully-functional GSM phone. This is as far as we are aware a first in the world of badges, and though it may not be a first in hacker camp connectivity it is still no mean achievement at the base station side. To find out more we talked to two of the people behind the network, on the radio side Lime Microsystems‘ [Andrew Back], and on the network side Nexmo‘s developer advocate, [Sam Machin].

There are sixteen base stations spread around the site, of which each one is a Raspberry Pi 3 B+ with a LimeSDR Mini. Development of the system was undertaken prior to the release of the Raspberry Pi Foundation’s PoE board, so they take a separate 24V supply which powers the Pi through a DC-to-DC converter. This arrangement allows for a significant voltage drop should any long cable runs be required.

On the software side the base stations all run the Osmocom (Open Source Mobile Communications) cellular base station infrastructure package. It was a fine decision between the all-in-one Osmocom NITB package and the fully modular Osmocom, going for the former for its reliability. It was commented that this would not necessarily be the case at a future event but that it made sense in the present. It appears on the network as a SIP phone system, meaning that it can easily integrate with the existing DECT network. Let’s take a look at how the network operates from the user side, and the licencing loophole that makes everything possible.

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