How To Run A First-Generation Cell Phone Network

June 2, 2021 by Zach Zeman 21 Comments

Retro tech is cool. Retro tech that works is even cooler. When we can see technology working, hold it in our hand, and use it as though we’ve been transported back in time; that’s when we feel truly connected to history. To help others create small time anomalies of their own, [Dmitrii Eliuseev] put together a quick how-to for creating your own Advanced Mobile Phone System (AMPS) network which can bring some of the classic cellular heroes of yesterday back to life.

Few readers will be surprised to learn that this project is built on software defined radio (SDR) and the Osmocom-Analog project, which we’ve seen before used to create a more modern GSM network at EMF Camp. Past projects were based on LimeSDR, but here we see that USRP is just as easily supported. [Dmitrii] also provides a brief history of AMPS, including some of the reasons it persisted so long, until 2007! The system features a very large coverage area with relatively few towers and has surprisingly good audio quality. He also discusses its disadvantages, primarily that anyone with a scanner and the right know-how could tune to the analog voice frequencies and eavesdrop on conversations. That alone, we must admit, is a pretty strong case for retiring the system.

The article does note that there may be legal issues with running your own cell network, so be sure to check your local regulations. He also points out that AMPS is robust enough to work short-range with a dummy load instead of an antenna, which may help avoid regulatory issues. That being said, SDRs have opened up so many possibilities for what hackers can do with old wireless protocols. You can even go back to the time when pagers were king. Alternatively, if wired is more your thing, we can always recommend becoming your own dial-up ISP.

Hackaday Podcast 119: Random Robot Writing, Slithering Snake Shenanigans, And Phased Array Phenomena

May 21, 2021 by Mike Szczys 2 Comments

Hackaday editors Mike Szczys and Elliot Williams pick up on the neatest hacks you may have missed. We start off with another “What’s that Sound?” so put your geeky-ears to the test and win a Hackaday Podcast T-shirt. Here are a couple of classic hacks to bring you joy: music based on Markov chains, and a squiggly take on the classic Nokia game of snake. For the more hardcore science geeks we dive into the B Meson news coming out of CERN’s physics experiments. And after taking a detour in bristle-bot-based pen plotting, we unpack the hidden system of pipes that carry oil, gas, diesel, and more from the refinery to your region.

Take a look at the links below if you want to follow along, and as always, tell us what you think about this episode in the comments!

Direct download (The best 57 MB you’ll download all day!)

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Coffee Cupping Is A Grind — Spectroscopy Could Brew Better Beans

May 1, 2021 by Kristina Panos 18 Comments

If you’ve ever bought whole coffee beans, chances are good that there was all kinds of information on the bag that led to your decision, like the origin, the roast type, and the flavor notes. Traditionally, coffee grading — that’s judging the aroma of both dry and wet grounds and slurping the coffee evenly across the tongue to determine the flavor profile — is done by humans in a process called cupping. To call it a process is too clinical — it’s really more like a ceremony performed with the grave sincerity that coffee deserves.

A traditional cupping ceremony. Image via Kaldi’s Coffee

There’s an industry standard coffee flavor wheel, so why not leverage that to make a robot that can remove the human bias and possible error of doing things the traditional way? That’s exactly what Demetria, a Columbian-Israeli company is doing.

They’ve developed an AI platform that can determine bean quality as judged by handheld scanners that were born on Kickstarter. The scanner uses near-infrared to look for biochemical markers in the bean, which it uses to match up with a profile backed by the all-knowing coffee flavor wheel.

Demetria is using SCiO scanners and a custom app to judge beans before they’re even roasted, which greatly speeds up the process but makes us wonder how green bean spectroscopy stacks up against roasted beans as judged by humans. You may remember the SCiO, a pocket-sized, connected spectrometer made by Consumer Physics that finally started delivering the goods a few years after funding. If you got your hands on a SCiO, you might like to know that there’s an open project out there to hack them. Sparkfun did a nice, thorough teardown, and it seems to be a well-engineered piece of hardware.

On the one hand, cupping is a tradition and thus may people feel that robbing coffee of this tradition will rob coffee of its soul. On the other hand, cupping is wasteful, as the coffee must be roasted and ground immediately prior to the ceremony and it requires the availability of Q graders who have been trained in the ways of coffee grading.

Want to know more about coffee production? Might as well learn the Retrotechtacular way.

[Main and thumbnail images via Demetria]

This Week In Security: Dan Kaminsky, Banned From Kernel Development, Ransomware, And The Pentagon’s IPv4 Addresses

April 30, 2021 by Jonathan Bennett 22 Comments

This week we’re starting off with a somber note, as Dan Kaminsky passed at only 42, of diabetic ketoacidosis. Dan made a name for himself by noticing a weakness in DNS response verification that could allow attackers to poison a target DNS resolver’s cache. A theoretical attack was known, where spoofed DNS responses could collide with requests, but Time-To-Live values meant that DNS requests only go out once per eight hours or so. The breakthrough was realizing that the TTL limitation could be bypassed by requesting bogus subdomains, and aiming the spoofed responses at those requests. This simple technique transformed a theoretical attack that would take 87 years to a very real 10 second attack. Check out the period video after the break, where Dan talked about his efforts in getting the problem fixed.
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You Won’t Believe How Much Tech Is Hiding In This Desk

April 20, 2021 by Kristina Panos 23 Comments

Say what you will about office life: there were definitely some productivity perks, but the coffee is much better at home. Like many of us, [Pierre] has been working from home for the last year or so. And as much as he might enjoy spending so much time in his small Parisian apartment, it lacks many of the amenities of the office such as a scanner, printer, and, you know, a reasonable amount of space in which to work.

Inspired by another build, [Pierre] set out to build his dream desk that is maximum PC power in minimum space. It is chock full of easily-accessible cavities that hide everything you’d expect, plus a few things you don’t, like a flatbed scanner, a printer, a router, and a wireless charging pad. One cavity is dedicated to I/O, and another has three international power sockets. The only thing it doesn’t hide is the 22″ pen display that [Pierre] uses for sketching, signing documents, and occasionally as a second monitor.

A home-brew jig makes consistent dowel drilling much easier.

This desk may look like solid wood, but the top is a veneer that’s glued on to a custom-cut 1mm steel sheet. The inside frame is made of hardwood and so are the legs — one of them has a hidden channel for the only two cords that are even somewhat visible — the power and Ethernet cables. He joined all the frame pieces with dowel rods, and made a 3D-printed and metal-reinforced drilling jig to get the holes just right.

[Pierre] started this build by planning out the components and making meticulous notes about the dimensions of every piece. Then he sketched it and modelled it in FreeCAD to get all the cavities and cable runs correct and ensure good airflow through the desk. After that it was on to woodworking, metalworking, and PCB fab for relocated and hidden display controls and a custom-built amplifier.

It’s obvious that a lot of thought went in to this, and there’s a ton of work appreciate here, so clear off that inferior desk of yours and check out the build video after the break. Wish you had a PC desk? [Pierre] is seriously considering a Kickstarter if enough people show interest.

Are you into minimalism, but don’t want to build something of this magnitude? There’s more than one way to get there.

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What To Expect From 3D Scanning, And How To Work With It

April 20, 2021 by Donald Papp 19 Comments

3D scanning and 3D printing may sound like a natural match for one another, but they don’t always play together as easily and nicely as one would hope. I’ll explain what one can expect by highlighting three use cases the average hacker encounters, and how well they do (or don’t) work. With this, you’ll have a better idea of how 3D scanning can meet your part design and 3D printing needs.

How Well Some Things (Don’t) Work

Most 3D printing enthusiasts sooner or later become interested in whether 3D scanning can make their lives and projects easier. Here are a three different intersections of 3D scanning, 3D printing, and CAD along with a few words on how well each can be expected to work.

Goal	Examples and Details	Does it work?
Use scans to make copies of an object.	3D scan something, then 3D print copies. Objects might be functional things like fixtures or appliance parts, or artistic objects like sculptures.	Mostly yes, but depends on the object
Make a CAD model from a source object.	The goal is a 1:1 model, for part engineering purposes. Use 3D scanning instead of creating the object in CAD.	Not Really
Digitize inconvenient or troublesome shapes.	Obtain an accurate model of complex shapes that can’t easily be measured or modeled any other way. Examples: dashboards, sculptures, large objects, objects that are attached to something else or can’t be easily moved, body parts like heads or faces, and objects with many curves. Useful to make sure a 3D printed object will fit into or on something else. Creating a CAD model of a part for engineering purposes is not the goal.	Yes, but it depends

In all of these cases, one wants a 3D model of an object, and that’s exactly what 3D scanning creates, so what’s the problem? The problem is that not all 3D models are alike and useful for the same things.

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Large Format Lego Camera Is A Bit Near-Sighted

April 19, 2021 by Zach Zeman 7 Comments

Photography doesn’t have to be expensive, something that’s especially true in the realm of film photography, where the imperfections of the medium can be half the appeal. There are many DIY plans and kits available for analog cameras, but [bhiga143] had couple spare components and a pile of small, colorful bricks lying around, so he decided to build a functional 4×5″ film camera out of Lego.

Details are light for this build, but with a little knowledge about camera structure we can guess at what’s going on inside. Simplicity makes for robust design, and what we have here is in effect a box with a lens on one side and photographic film on the other. The center section of the front, which actually supports the lens, is capable of sliding in and out to adjust focus. On the far side (not pictured) is a slot just wide enough to insert a standard film holder.

The camera really is a hack. [bhiga143] stayed true to the “Lego” part of Lego camera, so there is no glue, no black paper lining, and no frills. The tripod is whatever stack of books lay underneath it. The lens is, quote, “barely functional”. There are light leaks galore, and it can’t focus beyond about 3 feet (1 meter). But every one of those points just makes us love it more. Every nugget of imperfection is a few words added to the story each picture tells. And we honestly can’t wait to see more pictures.

Other Lego cameras we’ve seen have been smaller and less colorful, but using a simple pinhole lens can reduce the overall cost. Of course, you’re not limited to Lego if you want to build your own pinhole camera. Although, the ubiquitous plastic bricks can also be useful in later stages of the film photography process.