The Future’s So Bright, I Gotta Wear LCDs

Whether it was rays from the Sun that made a 150 million kilometer trip just to ruin your day or somebody’s unreasonably bright aftermarket headlights, at some point or another we’ve all experienced the discomfort of bright spots in our eyes. But short of wearing welder’s goggles all the time, what can we do? Luckily for us, [Nick Bild] has come up with a solution. Sort of.

Modifying the LCD so it can be seen through.

By adding LCDs to a pair of standard sunglasses, [Nick] has created something he’s calling “Light Brakes”. The idea is that the LCDs, having their backings removed, can essentially be used as programmable shutters to block out a specific part of the image that’s passing through them. With the addition of a Raspberry Pi and a camera, the Light Brakes can identify an unusually bright source of light and block it from the wearer’s vision by drawing a sufficiently large blob on the LCDs.

At least, that’s the idea. As you can see in the video after the break, the LCDs ability to block out a moving source of light is somewhat debatable. It’s also unclear what, if any, effect the “blocking” would have on UV, so you definitely shouldn’t try looking at the sun with a pair of these.

That said, a refined version of the concept could have some very interesting applications. For instance, imagine a pair of glasses that could actively block out advertisements or other unpleasant images from your field of vision. If this all sounds a bit like something out of an episode of Black Mirror, that’s because it is.

Attentive readers may have noticed that this isn’t the first time these fashionable frames have graced the pages of Hackaday. Over the summer they were used in a very interesting field of view home automation project that [Nick] was working on. This also isn’t the first time he’s stuck a pair of small LCDs in front of his eyes in the name of progress. We’re starting to identify something of a trend here, though we certainly aren’t complaining.

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Advertise Your Conference Schedule Via SSID

Whether it’s been a Python script running on a Linux box or an ESP8266, abusing using WiFi SSIDs to convey messages is hardly a new trick. But for DerbyCon 2019, [vgrsec] wanted to do put together something a little unique. Dare we say, even useful. Rather than broadcast out SSID obscenities or memes, this Raspberry Pi created fake WiFi networks that told everyone what talks were coming up.

The concept here is fairly simple: there’s a text file in /boot that contains the truncated names of all the talks and workshops in the schedule, one per line, and each line starts with the time that particular event is scheduled for. The script that [vgrsec] wrote opens this text file, searches for the lines beginning with the current time, and generates the appropriate SSIDs. With the number of tracks being run at DerbyCon, that meant there could be as many as five SSIDs generated at once.

Now in theory that would be enough to pull off this particular hack, but there’s a problem. The lack of an RTC on the Raspberry Pi means it can’t keep time very well, and the fact that the WiFi adapter would be busy pumping out SSIDs meant the chances of it being able to connect to the Internet and pull down the current time over NTP weren’t very good.

As the system was worthless without a reliable way of keeping time, [vgrsec] added an Adafruit PiRTC module to the mix. Once the time has been synchronized, the system could then run untethered via a USB battery bank. We might have put it into an enclosure so it looks a little less suspect, but then again, there were certainly far more unusual devices than this to be seen at DerbyCon.

Of course, if you’re OK with just dumping the entire schedule out at once and letting the user sift through the mountain of bogus SSIDs themselves, that’s even easier to accomplish.

A Miniature Radio Telescope In Every Backyard

You probably wouldn’t expect to see somebody making astronomical observations during a cloudy day in the center of a dense urban area, but that’s exactly what was happening at the recent 2019 Philadelphia Mini Maker Faire. Professor James Aguirre of the University of Pennsylvania was there demonstrating the particularly compact Mini Radio Telescope (MRT) project built around an old DirecTV satellite dish and a smattering of low-cost components, giving visitors a view of the sky in a way most had never seen before.

Thanks to the project’s extensive online documentation, anyone with a spare satellite dish and a couple hundred dollars in support hardware can build their very own personal radio telescope that’s capable of observing objects in the sky no matter what the time of day or weather conditions are. Even if you’re not interested in peering into deep space from the comfort of your own home, the MRT offers a framework for building an automatic pan-and-tilt directional antenna platform that could be used for picking up signals from orbiting satellites.

With the slow collapse of satellite television in the United States these dishes are often free for the taking, and a fairly common sight on the sidewalk come garbage day. Perhaps there’s even one (or three) sitting on your own roof as you read this, waiting for a new lease on life in the Netflix Era.

Whether it’s to satisfy your own curiosity or because you want to follow in Professor Aguirre’s footsteps and use it as a tool for STEM outreach, projects like MRT make it easier than ever to build a functional DIY radio telescope.

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Building A Laser Head With High Speed, High Resolution

A test exposure on cyanotype paper shows off the prototype’s resolution, around 100 microns.

Typically, when it comes to scanning a laser, it’s done with galvos or a rotating mirror assembly. However, these methods can be slow and cumbersome, or restricted due to existing patents. [Rick] aimed to find an alternative solution with the Hexastorm project, using a rotating prism to build a high speed, high resolution laser head.

The project currently uses a Beaglebone for the brains, with a polygon motor sourced from a photocopier used to rotate the prism at over 20,000 rpm. The project aims to be a proof of concept for rotating prism technology, which can then be adapted to specific tasks. With the promise of high speed and high resolution, the system could be used in fields as diverse as PCB manufacture, 3D resin printing, and even virtual reality displays. [Rick] explores these potential markets in a pitch deck, comparing to existing solutions in the marketplace.

If you’re interested in high performance optical systems, [Rick]’s work makes compelling reading. It’s not the first time we’ve explored cutting edge laser hacks, either. Video after the break. Continue reading “Building A Laser Head With High Speed, High Resolution”

Grind Your Welds With Pride, If That’s The Way You Do It

To grind or not to grind? What a question! It all depends on what you’re really trying to show, and in the case of welded joints, I often want to prove the integrity of the weld.

My ground-back piece of welded tube. Eagle-eyed readers will spot that the grinding reveals a weld that isn't perfect.
My ground-back piece of welded tube. Eagle-eyed readers will spot that the grinding reveals a weld that isn’t perfect.

Recently, I wrote a piece in which I talked about my cheap inverter welder and others like it. As part of it I did a lower-current weld on a piece of thin tube and before snapping a picture of the weld I ground it back flat. It turns out that some people prefer to see a picture of the weld bead instead — the neatness of the external appearance of the weld — to allow judgment on its quality. Oddly I believe the exact opposite, that the quality of my weld can only be judged by a closer look inside it, and it’s this point I’d like to explore.

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Creepy Halloween Doll Might Make You Betsy Wetsy

If you want to terrify your neighborhood this Halloween, you might go for the old standbys like skeletons or zombies. But you don’t have to go gory to find glory. Consider the talking doll. Those things are creepy enough already, right? Well, [cabuu] says no, the doll should be animated with servos and have remote control. She should still be able to talk, just not when you expect her to.

Forget pushing on her stomach, ’cause Baby’s got a Wemos D1 mini and her own Blynk app now.¬† A set of sliders in the app control a micro servo that animates her eyes, and another servo that twists her head from side to side. Her head doesn’t go all the way ’round, but that’s probably for the best. There are preset fright modes [cabuu] can set and forget until she springs to life via motion sensor.

We particularly like the bracket [cabuu] designed and printed that joins the eyeballs with the servo, along with his clever use of printed mate brackets to hold the servos in place within the head. If you think you can stomach it, there’s a demo video after the break. Stay tuned for total doll dissection after that as [cabuu] builds and inserts the terrifying tidbits.

We love hacks that combine innocence with insanity. Have you ever seen Thomas the Tank Engine singing Rick Astley?

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