Chasing The Electron Beam At 380,000 FPS

January 29, 2018 by 20 Comments

Analog TV is dead, but that doesn’t make it any less awesome. [Gavin and Dan], aka The Slow Mo Guys recently posted a video about television screens. Since they have some incredible high-speed cameras at their disposal, we get to see the screens being drawn, both on CRT and more modern LCD televisions.

Now we all know that CRTs draw one pixel at a time, drawing from left to right, top to bottom. You can capture this with a regular still camera at a high shutter speed. The light from a TV screen comes from a phosphor coating painted on the inside of the glass screen. Phosphor glows for some time after it is excited, but how long exactly? [Gavin and Dan’s] high framerate camera let them observe the phosphor staying illuminated for only about 6 lines before it started to fade away. You can see this effect at a relatively mundane 2500 FPS.

Cranking things up to 380,117 FPS, the highest speed ever recorded by the duo, we see even more amazing results. Even at this speed, quite a few “pixels” are drawn each frame. [Gavin] illustrates that by showing how Super Mario’s mustache is drawn in less than one frame of slow-mo footage. You would have to go several times faster to actually freeze the electron beam. We think it’s amazing that such high-speed analog electronics were invented and perfected decades ago.

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The Noisiest Seven-Segment Display Ever

January 29, 2018 by 30 Comments

Few mechanical clocks are silent, and many find the sounds they make pleasant. But the stately ticking of an old grandfather clock or the soothing sound of a wind-up alarm clock on the nightstand are nothing compared to the clattering cacophony that awaits [ProtoG] when he finishes the clock that this electromechanical decimal to binary to hex converter and display will be part of.

Undertaken as proof of concept before committing to a full six digit clock build, we’d say [ProtoG] is hitting the mark. Yes, it’s loud, but the sound is glorious. The video below shows the display being put through its paces, and when the clock rate ramps up, the rhythmic pulsations of the relays driving the seven-segment flip displays is hypnotizing. The relays, one per segment of the Alfa Zeta flip displays, have DPDT contacts wired to flip a segment by reversing polarity. As a work in progress, [ProtoG] hasn’t shared many more details yet, but he promises to keep us up to date on the converter aspect of the circuit. Right now it just seems like a simple but noisy driver. We’ll be following this one with interest.

If you prefer your clocks quieter but still like funky displays, check out this mixed media circus-themed clock.

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Opt-Out Fitness Data Sharing Leads To Massive Military Locations Leak

January 28, 2018 by 79 Comments

People who exercise with fitness trackers have a digital record of their workouts. They do it for a wide range of reasons, from gathering serious medical data to simply satisfying curiosity. When fitness data includes GPS coordinates, it raises personal privacy concerns. But even with individual data removed, such data was still informative enough to spill the beans on secretive facilities around the world.

Strava is a fitness tracking service that gathers data from several different brands of fitness tracker — think Fitbit. It gives athletes a social media experience built around their fitness data: track progress against personal goals and challenge friends to keep each other fit. As expected of companies with personal data, their privacy policy promised to keep personal data secret. In the same privacy policy, they also reserved the right to use the data shared by users in an “aggregated and de-identified” form, a common practice for social media companies. One such use was to plot the GPS data of all their users in a global heatmap. These visualizations use over 6 trillion data points and can be compiled into a fascinating gallery, but there’s a downside.

This past weekend, [Nathan Ruser] announced on Twitter that Strava’s heatmap also managed to highlight exercise activity by military/intelligence personnel around the world, including some suspected but unannounced facilities. More worryingly, some of the mapped paths imply patrol and supply routes, knowledge security officers would prefer not to be shared with the entire world.

This is an extraordinary blunder which very succinctly illustrates a folly of Internet of Things. Strava’s anonymized data sharing obsfucated individuals, but didn’t manage to do the same for groups of individuals… like the fitness-minded active duty military personnel whose workout habits are clearly defined on these heat maps. The biggest contributor (besides wearing a tracking device in general) to this situation is that the data sharing is enabled by default and must be opted-out:

“You can opt-out of contributing your anonymized public activity data to Strava Metro and the Heatmap by unchecking the box in this section.” —Strava Blog, July 2017

We’ve seen individual fitness trackers hacked and we’ve seen people tracked through controlled domains before, but the global scope of [Nathan]’s discovery puts it in an entirely different class.

[via Washington Post]

More Than Just An Atari Look-Alike

January 28, 2018 by 4 Comments

The Raspberry Pi has been a boon for hackers with a penchant for retro gaming. Redditor [KaptinBadkruk] Wanted to get on board the game train and so built himself an Atari 2600-inspired Raspberry Pi 3 console!

A key goal was the option to play Nintendo 64 titles, so [KaptinBadkruk] had to overclock the Pi and then implement a cooling system. A heatsink, some copper pads, and a fan from an old 3D printer — all secured by a 3D printed mount — worked perfectly after giving the heatsink a quick trim. An old speaker and a mono amp from Adafruit — and a few snags later — had the sound set up, with the official RPi touchscreen as a display.

After settling on an Atari 2600-inspired look, [KaptinBadkruk] laboured through a few more obstacles in finishing it off — namely, power. He originally intended for this  project to be portable, but power issues meant that idea had to be sidelined until the next version. However — that is arguably offset by [KaptinBadkruk]’s favourite part: a slick 3D Printed item box from Mario Kart front and center completes the visual styling in an appropriately old-meets-new way.

That item block isn’t the first time a lightshow has accompanied an Atari console, but don’t let that stop you from sticking one in your pocket.

[Via /r/DIY]

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Hackaday Links: January 28, 2018

January 28, 2018 by 14 Comments

In case you haven’t heard, we have a 3D printing contest going on right now. It’s the Repairs You Can Print Contest. The idea is simple: show off how you repaired something with a 3D printer. Prizes include $100 in Tindie credit, and as a special prize for students and organizations (think hackerspaces), we’re giving away a few Prusa i3 MK3 printers.

[Drygol] has made a name for himself repairing various ‘home’ computers over the years, and this time he’s back showing off the mods and refurbishments he’s made to a pile of Amiga 500s. This time, he’s installing some new RAM chips, fixing some Guru Meditations by fiddling with the pins on a PLCC, adding a built-in modulator, installing a dual Kickstart ROM, and installing a Gotek floppy adapter. It’s awesome work that puts all the modern conveniences into this classic computer.

Here’s an FPGA IoT Controller. It’s a Cyclone IV and a WiFi module stuffed into something resembling an Arduino Mega. Here’s the question: what is this for? There are two reasons you would use an FPGA, either doing something really fast, or doing something so weird normal microcontrollers just won’t cut it. I don’t know if there is any application of IoT that overlaps with FPGAs. Can you think of something? I can’t.

Tide pods are flammable.

You know what’s cool? Sparklecon. It’s a party filled with a hundred pounds of LEGO, a computer recycling company, a plasmatorium, and a hackerspace, tucked away in an industrial park in Fullerton, California. It’s completely chill, and a party for our type of people — those who like bonfires, hammer Jenga, beer, and disassembling fluorescent lamps for high voltage transformers.

A few shoutouts for Sparklecon. The 23b Hackerspace is, I guess, the main host here, or at least the anchor. Across the alley is NUCC, the National Upcycled Computing Collective. They’re a nonprofit that takes old servers and such, refurbishes them, and connects them to projects like Folding@Home and SETI@Home. This actually performs a service for scientists, because every moron is mining Bitcoin and Etherium now, vastly reducing the computational capabilities of these distributed computing projects. Thanks, OSH Park, for buying every kind of specialty pizza at Pizza Hut. I would highly encourage everyone to go to Sparklecon next year. This is the fifth year, and it’s getting bigger and better every time.

ESP32 Makes For World’s Worst Radio Station

January 28, 2018 by 14 Comments

We can say one thing for [bitluni]: the BOMs for his projects, like this ESP32 AM radio transmitter, are always on the low side. That’s because he leverages software to do jobs traditionally accomplished with hardware, always with instructive results.

In this case, the job at hand is creating an RF oscillator in the broadcast AM band and modulating some audio onto it. From his previous experience using an ESP32 to watch video on an oscilloscope, [bitluni] knew that the microcontroller’s DACs were up to the task of producing an 800-kHz signal, and he managed to produce a more-or-less sine wave carrier with some clever code. His sketch takes data from a header file, modulates it onto the carrier, and sends it out over the ether using a short stub of wire for an antenna. The range is severely limited, but for what it is, it gets the job done and shows the basics. And as a bonus, [bitluni] included a bit of JavaScript that turns an audio file into a header file that’s ready to go out over the airwaves for all your trolling needs.

If you’re looking for a little more range for your low power transmitter and you’re a licensed amateur operator, you might want to explore the world of QRP radio.

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Arcade Style Computer Hotkeys

January 28, 2018 by 9 Comments

Prolific maker [Sean Hodgins] has taken the wraps off of his latest one-day build, and as usual, it takes the kind of spare parts most people reading Hackaday will have in their parts bins and turns it into something fun and useful. This time around, he takes a bunch of spare arcade-style buttons he had from a previous project and combines them with an Adafruit Trinket (SAMD21 flavor) to make a USB input device for his computer.

[Sean] uses 1/4 inch acrylic to make the case, though he does mention that it could just as easily be 3D printed. But using the acrylic is easy and gives a nice glossy look to the final hardware. With a saw and a drill press you can make some very professional cases out of acrylic, which goes to show that you don’t necessarily need to have a high end 3D printer to create great looking enclosures.

As explained in the video, the Adafruit Trinket is not strictly necessary for this build, it’s just what [Sean] had lying around. Any microcontroller that can present itself to the operating system as a USB Human Interface Device (HID) will work fine for a project like this.

Software wise, a modified Arduino demo program is used to equate the states of the digital pins to pre-defined key combinations to be sent to the computer. In this simple example the key combinations are hard-coded into the Trinket’s source code, but a future enhancement could be adding a method of setting up new key combinations with a configuration tool.

We’ve covered our fair share of non-traditional USB input devices, all operating on largely the same principle. As it turns out, hackers have quite a pension for making oddball input devices.

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