Have you ever taken a picture indoors and had unsightly black bars interrupt your otherwise gorgeous photo? They are caused by lighting which flickers in and out in its normal operation. Some people can sense it easier than others without a camera. The inconsistent light goes out so briefly that we usually cannot perceive it but run-of-the-mill camera phones scan rows of pixels in sequence, and if there are no photons to detect while some rows are scanned, those black bars are the result. Annoying, right?
What if someone dressed that bug of light up as a feature? Instead of ruining good photos, researchers at the University of California-San Diego and the University of Wisconsin-Madison have found out what different frequencies of flicker will do to a photograph. They have also experimented with cycling through red, green, and blue to give the effect of a poorly dubbed VHS.
There are ways an intelligent photographer could get around the photo-ruining effect with any smartphone. Meanwhile DSLR cameras are already immune and it won’t work in sunlight, so we are not talking about high security image protection. The neat thing is that this should be easy to replicate with some RGB strips and a controller. This exploits the row scanning of new cameras, so some older cameras are immune.
We’ve all got a box full of old PCBs, just waiting to be stripped of anything useful. [Dennis1a4] decided to do something with his, turning it into an attractive mosaic that he hung on the wall of his new workshop. But this isn’t just a pile of old PCBs: [Dennis1a4] decided to use the LEDs that were on many of the old boards, creating a blinky junk build. That’s kind of neat in itself, but he then decided to go further, building in an IR receiver so he could control the blinkiness, and a PIR sensor that detected when someone was near the mosaic.
This whole setup is controlled by an ATMega328p that is driving a couple of PCF8575 port expanders that drive the LEDs. These blink in Morse code patterns. [Dennis1a4] also used an array of DIP switches on one of the boards to randomize the patterns, and wired in a pizeo buzzer on another board to make appropriate bleepy noises.
Continue reading “PCB Junk Drawer Turned Into Blinky Mosaic”
How often do you find yourself having to pause a project to make a test circuit or write some test code to find the source of a problem? Do enough variations of the same test and you’ll eventually make a dedicated test tool. That’s just what [Devon Bray] found himself doing.
[Devon] does a lot of work with addressable LEDs of different types and after much experience, created the BlinkBox, a dedicated test tool for addressable LEDs. It supports multiple LED chipsets, you can give it a count of the LEDs you want to light up, and you can choose a test animation. It even writes your settings to an EEPROM so you that don’t have to repeat yourself when you next turn it on.
He’s also done a very nice job packaging it all up, creating a 3D printed case, using backlit buttons for working in the dark, and even added a contrast knob for the LCD screen. Kudos to him for all the effort he’s put making this polished. Everything you need to duplicate it is available on his webpage, along with the schematic for the curious. Watch it in action, or just admire his handiwork in the video below.
Continue reading “BlinkBox: Debugging Tool For Addressable LEDs”
With the June solstice right around the corner, it’s a perfect time to witness first hand the effects of Earth’s axial tilt on the day’s length above and beyond 60 degrees latitude. But if you can’t make it there, or otherwise prefer a more regular, less deprived sleep pattern, you can always resort to simulations to demonstrate the phenomenon. [SimonRob] for example built a clock with a real time rotating model of Earth to visualize its exposure to the sun over the year.
The daily rotating cycle, as well as Earth’s rotation within one year, are simulated with a hand painted plastic ball attached to a rotating axis and mounted on a rotating plate. The hand painting was done with a neat trick; placing printed slivers of an atlas inside the transparent orb to serve as guides. Movement for both axes are driven by a pair of stepper motors and a ring of LEDs in the same diameter as the Earth model is used to represent the Sun. You can of course wait a whole year to observe it all in real time, or then make use of a set of buttons that lets you fast forward and reverse time.
Earth’s rotation, and especially countering it, is a regular concept in astrophotography, so it’s a nice change of perspective to use it to look onto Earth itself from the outside. And who knows, if [SimonRob] ever feels like extending his clock with an aurora borealis simulation, he might find inspiration in this northern lights tracking light show.
This is a spectacular showpiece and a great project you can do with common tools already in your workshop. Once you’ve mastered earth, put on your machinists hat and give the solar system a try.
You may laugh off the ukulele as a toy or joke instrument, and admittedly, their starting price tag and the quality that usually comes with such a price tag doesn’t help much to get a different opinion on that. But it also makes it the perfect instrument for your next project. After all, they’re easy to handle, portable, and cheap enough to use a drill and other tools on them without too much regret. Plus, a little knowledge to play can get you far, and [Elaine] can teach you the essential, “all the pop songs use it”, four chords with her Arduino powered LED Ukulele.
As first step, [Elaine] drilled holes in her ukulele’s fingerboard to place some LEDs at all the positions required to play the four chords C, G, Am, and F. Connected to an Arduino attached to the ukulele’s back, each chord will light up its associated LEDs to indicate the finger positions required to play the chord itself. Taking the teaching part a step further, her next step is to extend each LED with a second, light sensing one, and read back if the fingers are placed at the correct position.
[Elaine] has already plans to turn the ukulele into an interactive game next. And if four chords are eventually not enough for you anymore, have a look at another LED based project teaching to play any major, minor and major seventh chord on the ukulele.
[JohnathonT] has a two-year-old who can’t reliably tell time just yet. Every morning, he gets up before the rooster crows and barges into his parents’ room, ready to face the day.
In an effort to catch a few more Zs, [JohnathonT] built a simple but sanity-saving clock that tells time in a visual, kid-friendly way. Sure, this is a simple build. But if a toddler is part of your reality, who has time to make one from logic gates? The hardware is what you’d expect to see: Arduino Nano, a DS1307 RTC, plus the LEDs and resistors. We think an RGB LED would be a nice way to mix up the standard stoplight hues a bit.
At a glance, little Mr. Rise and Shine can see if it’s time to spread cheer, or if he has to stay in his room and play a bit longer. At 6:00AM, the light powers on and glows red. At 6:50, it turns yellow for 10 minutes. At the first reasonable hour of the day, 7:00AM, it finally turns green. In reading the code, we noticed that it also goes red at 8:00PM for 45 minutes, which tells us it also functions as a go-to-sleep indicator.
When his son is a little older, maybe [JohnathonT] could build him a clock that associates colors with activities.
Got a broken laptop screen sitting around? If you haven’t already pilfered the LEDs and used the polarizing sheets for screen privacy filters, why not turn it into a unique table lamp? See if you can use more parts of the screen than [alexmaree-ross] did.
This is a simple idea with great-looking results, but the process is a bit fiddly. After all the layers are separated and the LEDs extracted, there’s still the matter of figuring out how they’re wired up. [alexmaree] tested them in pairs to see how they’re grouped together and ultimately powered them with a transformer from an old printer. To build the case, [alexmaree] carefully scored and snapped the pieces from the plastic layer and carefully glued pieces of the polarizing layer on top to give it that underwater infinity mirror look. The finishing touch comes from edging the shade with thin metal from the bezel.
The case could be in any shape you want, but we think the prism is quite appropriate considering the polarizing effects. And it looks really cool when you walk around it, which you can do vicariously after the break.
If the screen still works but laptop doesn’t, why not drive it with an FPGA?
Continue reading “Broken Screen Becomes Polarizing Art Lamp”