Secret Messages Could Be Hiding In Your Server Logs

August 28, 2019 by Tom Nardi 13 Comments

[Ryan Flowers] writes in with a clever little hack that can allow you to hide data where nobody is going to go looking for it. By exploiting the fact that a web server will generally log all HTTP requests whether or not it’s valid, he shows how you can covertly send a message by asking the server for a carefully crafted fictitious URL.

We aren’t talking about requesting “yousuck.txt” from the server that hosts your least favorite website, either. As [Ryan] demonstrates, you can compress a text file, encode it with uuencode, and then send it line by line to the destination server with curl. He shows how the process, which he calls “CurlyTP” can be done manually on the command line, but it would be a simple matter of wrapping it up in a Bash script.

To get the message back, you just do the opposite. Use grep to find the lines in the log file that contain the encoded data, and then put them through uudecode to get the original text back. Finding the appropriate lines in the log file is made easier by prepending a prearranged keyword to the beginning of the URL requests. The keyword can be changed for each message to make things easier to keep track of.

If you’re still wondering why anyone would go through the trouble to do this, [Ryan] provides an excellent example: a covert “dead drop” where people could leave messages they’d rather not send through the usual channels. As long as the sender used a service to mask their true IP address, they could anonymously deliver messages onto the server without having to use any special software or protocol they might not have access to. Even the most restrictive firewalls and security measures aren’t likely to be scanning URLs for compressed text files.

We’ve seen web-based dead drops done with Python in the past, and even purpose built “PirateBoxes” that allow people to covertly exchange files, but we like how this method doesn’t require any special configuration on the server side. You should check your server logs, somebody might be trying to tell you something.

Trimmed Dreamcast Board Makes For Perfect Portable

August 27, 2019 by Tom Nardi 4 Comments

In the last year or so we’ve been seeing an array of portable game system builds based around “trimmed” Wii motherboards which have literally been cut down to a fraction of their original size. It turns out that most of the board is dedicated to non-essential functions, with the core Wii system contained within one specific area that can be isolated with a steady hand. But as [Gman] shows in his latest build, the same concept can also be applied to the Sega Dreamcast.

But of course, there’s a bit more to it than just taking a hacksaw to a Dreamcast motherboard. [Gman] had to supplement the trimmed system with quite a bit of additional hardware, such as a power management board he originally designed for portable Wii projects.

Other components were specifically built for this project. For example there’s a custom PCB that handles emulating the Dreamcast controller using a PIC32MZ microcontroller. He’s also using a LM49450 to pull digital audio from the motherboard over I2S, completely bypassing the analog output.

While not currently functioning, [Gman] also included an SPI OLED display and the hardware necessary to emulate basic functionality of the system’s unique Visual Memory Unit (VMU) right in the front of the system. We’re looking forward to seeing him revisit this feature in the future when he’s got the software side of things worked out.

The Nintendo 2DS inspired enclosure is completely 3D printed. A Prusa i3 with textured PEI bed was used to achieve the gorgeous dappled look on the system’s front panel, while the buttons were done on a Form 2 SLA printer. With a mold made from the printed buttons, [Gman] was able to cast the final pieces using a variety of colors until he found a combination he was happy with.

If you’re not Team Sega and would rather hack up your own tiny versions of Nintendo’s hardware, look no further than this fully functional trimmed Wii built into an Altoids tin.

3D Printed Rover Enjoys Long Walks On The Beach

August 27, 2019 by Tom Nardi 13 Comments

More than a few hackers have put in the considerable time and effort required to build a rover inspired by NASA’s robotic Martian explorers, but unfortunately even the most well funded home tinkerer can’t afford the ticket to send their creation offworld. So most of these builds don’t journey through anything more exciting than a backyard sandbox. Not that we can blame their creators, we think a homebrew rover will look just as cool in your living room as it would traipsing through a rock quarry.

But the DIY rover status quo clearly wasn’t sufficient for [Jakob Krantz], who decided the best way to test his new Curiosity-inspired rover was to let it frolic around on the beach for an afternoon. But judging by the video after the break, his beefy 3D printed bot proved to be more than up to the task; powering through wildly uneven terrain with little difficulty.

Beyond a few “real” bearings here and there, all of the key components for the rover are 3D printed. [Jakob] did borrow a couple existing designs, like a printable bearing he found on Thingiverse, but for the most part he’s been toiling away at the design in Fusion 360 and using images of the real Curiosity rover as his guide.

Right now, he’s controlling the rover with a standard 6 channel RC receiver. Four channels are mapped to the steering servos, and a fifth to the single electronic speed control that commands the six wheel motors. But he’s recently added an Arduino to the rover which will eventually be in charge of interpreting the RC commands. This will allow more complex maneuvers with fewer channels, such as the ability to rotate in place.

We’re proud to count our very own [Roger Cheng] among the rover wrangling hackers of the world. An entire community has sprung up around his six-wheeled Sawppy, and the knowledge gained during its design and construction could be applicable to any number of other projects.

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3D Printed Pen Plotter Is As Big As You Need It To Be

August 26, 2019 by Tom Nardi 17 Comments

There’s nothing quite like building something to your own personal specifications. It’s why desktop 3D printers are such a powerful tool, and why this scalable plotter from the [Lost Projects Office] is so appealing. You just print out the end pieces and then pair it with rods of your desired length. If you’ve got some unusually large computer-controlled scribbling in mind, this is the project for you.

The design, which the team calls the Deep Ink Diver (d.i.d) is inspired by another plotter that [JuanGg] created. While the fundamentals are the same, d.i.d admittedly looks quite a bit more polished. In fact, if your 3D printed parts look good enough, this could probably pass for a commercial product.

For the electronics, the plotter uses an Arduino Uno and a matching CNC Shield. Two NEMA 17 stepper motors are used for motion: one to spin the rod that advances the paper, and the other connected to a standard GT2 belt and pulley to move the pen back and forth.

We particularly like the way [Lost Projects Office] handled lifting the pen off the paper. In the original design a solenoid was used, which took a bit of extra circuitry to drive from the CNC Shield. But for the d.i.d, a standard SG90 servo is used to lift up the arm that the pen is attached to. A small piece of elastic puts tension on the assembly so it will drop back down when the servo releases.

If this plotter isn’t quite what you’re after, don’t worry. There’s more where that came from. We’ve seen a number of very interesting 3D printed plotters that are just begging for a spot in your OctoPrint queue.

Glia Is Making Open Medical Devices, And You Can Help

August 25, 2019 by Tom Nardi 40 Comments

The Glia project aims to create a suite of free and open-source medical equipment that can be assembled cheaply and easily when and where it’s needed. Even essential tools like stethoscopes and tourniquets can be difficult to acquire in certain parts of the world, especially during times of war or civil unrest. But armed with a 3D printer and the team’s open-source designs, an ad-hoc factory can start producing these lifesaving tools anywhere on the planet.

Glia member [Tarek Loubani] has recently written a blog post discussing the team’s latest release: an otoscope that can be built for as little as $5. Even if you don’t recognize the name, you’ve almost certainly seen one of them in use. The otoscope is used to look inside the ear and can be invaluable in diagnosing illnesses, especially in children. Unfortunately, while this iconic piece of equipment is quite simple on a technical level, professional-quality versions can cost hundreds of dollars.

Now to be fair, you’ll need quite a bit more than just the 3D printed parts to assemble the device. The final product requires some electrical components such as a battery holder, rocker switch, and LED. It also requires a custom lens, though the Glia team has thought ahead here and provided the files for printable jigs that will allow you to cut a larger lens down to the size required by their otoscope. In a situation where you might have to improvise with what you have, that’s a very clever design element.

So far the team is very happy with how the otoscope performs, but they’ve run into a bit of a logistical snag. It turns out that early work on the project was done in the web-based TinkerCAD, which isn’t quite in line with the team’s goals of keeping everything free and open. They’d like some assistance in recreating the STLs in FreeCAD or OpenSCAD so they’re easier to modify down the road. So if you’re a FOSS CAD master and want to earn some positive karma, head over to the GitHub page for the project and put those skills to use.

We’ve previously covered Glia’s work with 3D printed tourniquets to treat gunshot wounds, a project that led to [Tarek] himself being shot by a sniper while attempting to field test the design in Gaza. If that’s not commitment to the principles of open-source hardware, we don’t know what is.

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DIY ZigBee Therapy Lights Are Hue Compatible

August 23, 2019 by Tom Nardi No comments

Working on a project into the wee hours is hardly uncommon for us hackers, but if you’re consistently sleeping until the afternoon, it’s possible you’re suffering from a condition known as Delayed Phase Sleep Disorder (DPSD). Put simply, your body’s internal clock is out of alignment with the world around you. One of the ways to treat this condition is to expose yourself to bright light in the morning, which can help you wake up and feel more refreshed. Unfortunately, these so-called “Bright Light Therapy” boxes tend to be pretty expensive.

Looking for a way to treat his own DPSD, [Edward Shin] decided to build his own light box based on the research he’d done on the various commercial offerings out there. After all, a box full of bright lights that operates on a timer doesn’t seem particularly complex. Of course, in reality there’s a bit more to it than that, but so far the results are certainly promising.

The first decision [Edward] had to make was what kind of light he wanted. Classic light therapy devices, often used to treat Seasonal Affective Disorder (SAD), tend to be full spectrum lights that try and simulate sunlight. But in his research, he found a paper from Nature that explained the melanopsin in the human eye responds primarily to blue and green light. But as intense blue light can apparently lead to macular degeneration, he decided to go with green.

Since [Edward] already uses the Philips Hue system for his home’s lighting, he wanted to bring his therapy light into that ecosystem. The idea was that he could easily schedule his new green light box to go on when he wanted to wake up in the morning. So he used the Mesh Bee from Seeed Studio which not only supports ZigBee, but for which software is available to emulate a Hue bulb. Then he just needed to pair that with a sufficiently beefy LED driver and some 510 nm emitters. Everything is enclosed in a box made of laser cut wood that’s designed to hang from the headboard and shine down onto his face.

Over the years we’ve seen a number of similar projects trying to address SAD, so the idea of a hacker tweaking the concept to tackle DPSD seems a natural enough evolution of the idea. Just remember to speak with a medical professional before coming up with a homebrew treatment plan.

OTA Flash Tool Makes Fitness Tracker Hacking More Accessible

August 23, 2019 by Tom Nardi 25 Comments

Over the last several months, [Aaron Christophel] has been working on creating a custom firmware for cheap fitness trackers. His current target is the “D6 Tracker” from a company called MPOW, which can be had for as little as $7 USD. The ultimate goal is to make it so anyone will be able to write their own custom firmware for this gadget using the Arduino IDE, and with the release of his new Android application that allows wirelessly flashing the device’s firmware, it seems like he’s very close to realizing that dream.

Previously, [Aaron] had to crack open the trackers and physically connect a programmer to update the firmware on the NRF52832-based devices. That might not be a big deal for the accomplished hardware hacker, but it’s a bit of a hard sell for somebody who just wants to see their own Arduino code running on it. But with this new tool, he’s made it so you can easily switch back and forth between custom and original firmware on the D6 without even having to take it off your wrist.

After the break, you can see the video that [Aaron] has put together which talks about the process of flashing a new firmware image. It’s all very straightforward: you simply pick the device from the list of detected BLE devices, the application puts the tracker into bootloader mode, and then you select the DFU file you want to flash.

There are a couple of ready-made firmwares you can put on the D6 right now, but where’s the fun in that? [Aaron] has put together a customized version of the Arduino IDE that provides everything you need to start writing and flashing your own firmware. If you’ve ever dreamed about creating a wearable device that works exactly the way you want, it’s hard to imagine a cheaper or easier way to get in on the action.

When we last heard from [Aaron] earlier this year, he was working on the IWOWN I6HRC tracker. But it looks like the availability of those devices has since dried up. So if you’re going to try your hand at hacking the MPOW D6, it might be wise to buy a few now while they’re still cheap and easy to find.

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