Painting With Light And A Little G-Code

Most photographs are made in the fraction of a second that the camera’s shutter is gathering reflected light from the scene. But there’s fun to be had by leaving the shutter open and directing light into the camera. Called light painting, it can be as simple as a camera on a tripod in a dark room and a penlight spelling out dirty words – not like we’d know – or as complicated as this CNC dot-matrix light printer.

The first idea that [Jeremy S. Cook] had for this build didn’t go so well. He fitted an LED to the gantry of his 3D-printer, intending to send it G-code representing bitmaps. The idea would be to set it up in a dark place, open the shutter, and let the machine build up the image by rastering through the X- and Y- axes while blinking the LED on and off at the right time. But since the gantry only moves in one axis, he abandoned the printer in favor of his CNC router. He printed a collar to fit the dust collector shroud we previously featured, added a battery-powered LED, and affixed a pushbutton switch to the let the Z-axis turn on the light. It took some tweaking such as adding a translucent PLA diffuser, to get decent images, but in the end it worked. We like the soft look of the floating voxels, which were really helped by the later addition of a Nano and a Neopixel. Check out the build in the video below.

One thing we’d suggest is better reflection control. [Jeremy] used a black platen as a background, but it wasn’t quite enough. We suggest going none more black next time.

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RGB Word Clock Doesn’t Skimp On The Features

Like most pieces of technology, word clocks seem to be getting better and better every year. As hackers get their hands on better microcontrollers and more capable LED controllers, these builds not only look more polished, but get improved features and functions. Luckily for us, the rise of these advanced modular components means they’re getting easier to build too. For an example of these parallel traits, look no further than VERBIS by [Andrei Erdei].

This colorful word clock is powered by an ESP8266, a 8×8 RGB LED matrix, and a WS2812 RGB LED controller module. [Andrei] used the diminutive ESP-01 which can plug right into the LED controller, and just needs a 3.3 VDC regulator board to complete the very compact electronics package.

To keep the LEDs from interfering with each other, [Andrei] has designed a 3D printed grid which fits over the matrix board. On top of that goes a piece of paper that has the letters printed on it. He mentions that he was able to get good results printing this “stencil” out on an inkjet printer by simply running the same piece of paper through a few times; picking up more black ink each time it went through. Judging by the sharp characters seen in the video after the break, the trick worked well.

With his hardware put together, [Andrei] turned his attention to the software. We really think the project shines here, as his clock not only supports NTP for automatically setting the time over the Internet, but offers a full web interface to control various functions such as the LED colors. You can even change the NTP server and network configuration right from the UI, which is a nice touch compared to just hard coding the values into the code. Even if you don’t use the same hardware, the open source control software is definitely something you should look into if you’re building your own word clock.

We recently covered another easy to build word clock that used an LED matrix and not a whole lot else, but it was quite tiny. This build is a much more reasonable size for a desk, but you’ll probably need to break out the laser cutter if you want to get much bigger.

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Cylindrical LED Display Comes Full Circle

According to [makeTVee], his latest project started out as an experiment to see how well the LED matrix techniques he’s worked with in the past would translate to a cylindrical form factor. We’re going to go ahead and say that not only was the test a success, but that the concept definitely holds promise for displays that are both functional and aesthetically pleasing. This build stops a bit short of being a complete implementation, but what he has so far is very promising and we hope he continues fleshing it out.

A laser cutter was used to create the interlocking segments that make up the display’s frame, but we imagine you could pull off a similar design using 3D printed parts if you don’t have access to a laser. Strips of WS2812 LEDs are mounted along the inside of the cylinder so that each individual LED lines up with the center of a cell. To finish off the outside of the cylinder [makeTVee] used a thin wood veneer called MicroWOOD, which gives the LEDs a nice diffused glow. The wood grain in the veneer also provides an organic touch that keeps the whole thing from looking too sterile.

Of course, a display like this only works if you’ve got software to drive it. To that end, [makeTVee] has used pygame to create a simulator on his computer that shows what the display would look like if it were unrolled and flattened it out. This makes it a lot easier to create content, as you can see the whole display at once. He says the source for the new tool will be coming to GitHub soon, and we’re very interested in taking a look.

If this display looks familiar, it’s probably because a distinctly flatter version of it took the top spot in our “Visualize it with Pi” contest last year.

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Hackaday Podcast 007: Everything Microcontrollers, Deadly Clock Accuracy, CT X-Rays, Mountains Of E-Waste

Elliot Williams and Mike Szczys look at all that’s happening in hackerdom. This week we dive deep into super-accurate clock chips, SPI and microcontroller trickery, a new (and cheap) part on the microcontroller block, touch-sensitive cloth, and taking a home X-ray to the third dimension. We’re saying our goodbyes to the magnificent A380, looking with skepticism on the V2V tech known as DSRC, and also trying to predict weather with automotive data. And finally, what’s the deal with that growing problem of electronic waste?

Links for all discussed on the show are found below. As always, join in the comments below as we’ll be watching those as we work on next week’s episode!

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 (60 MB or so.)

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Lighting Up The Night Sky With A Flying POV Display

We’ve seen loads of persistence of vision displays before, but this sky-writing POV display seems as though it may be a first. And we have to agree with its creators that it’s pretty cool.

The idea man on this was [Ivan Miranda], who conceived of a flying POV as a twist on his robotic dot-matrix beach printer. But without any experience in RC flight, he turned to fellow YouTuber [Tom Stanton], whose recent aerial builds include this air-powered plane, for a collaboration. [Ivan]’s original concept was a long strip of Neopixels that would be attached to the underside of a wide-wingspread plane. WIthout much regard for the payload limits of most RC planes, he came up with a working display that was 3 meters long. His video below shows it in use in his shop, with some pretty impressive long exposure images.

[Tom]’s part was to make the POV display flyable. He cut the length down to 2 meters and trimmed the weight enough to mount it to a quadcopter. Ungainly as the machine was, he was able to master its control enough to start painting pictures across the twilight sky. The images at the end of his video are actually stunning – we’re especially fond of Thunderbird 2, which takes us back to our childhood.

We’re not sure what the practical uses of this are, but that’s hardly the point. It’s enough that it’s an interesting project from an unlikely duo. Continue reading “Lighting Up The Night Sky With A Flying POV Display”

Disco Ain’t Dead: Blinky Ball Makes You Solder Inside A Dome

Disco balls take a zillion mirrors glued to a sphere and shine a spotlight on them. But what if the ball itself was the light source? Here’s a modern version that uses addressable LEDs in a 3D-printed sphere that also hides the electronics inside the ball itself.

Check out the video below to see the fantastic results. It’s a Teensy 3.6 driving a whopping 130 WS2812 LEDs to make this happen. (Even though the sphere has the lowest surface area to volume ratio.) There’s even a microphone and an accelerometer to make the orb interactive. Hidden inside is a 4400 mAh battery pack that handles recharging and feeds 5 V to the project.

For us, it’s the fabrication that really makes this even more impressive. The sphere itself is 3D printed as four rings that combine to form a sphere. This makes perfect spacing for the LEDs a snap, but you’re going to spend some time soldering the voltage, ground, and data connections from pixel to pixel. In this case that’s greatly simplified because the LEDs were sourced from AliExpress already hosted on a little circle of PCB so you’re not trying to solder on the component itself. Still, that’s something like 390 wires requiring 780 solder joints!

We love seeing an LED ball you can hold in your hand. But if you do want something bigger, try this 540 LED sphere built from triangular PCBs.

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Internet-connected Advent calendar

Advent Calendar Tracks The Days Until Christmas

Internet-connected Advent calendarWhat’s a hacker to do when Halloween’s over and a new source of ideas is needed for more hacks? Make something for Christmas of course. That’s what [Dario Breitenstein] did when he made his Advent calendar both as a decoration and to help instill some Christmas spirit.

Designed in SketchUp, it’s a WS2812 LED strip mounted in a clean looking walnut enclosure. The light diffuses through 3D-printed PETG lids with vinyl over them to outline the days. Naturally, it had to be Internet-connected and so an ESP8266 based WEMOS D1 mini board fetches the date and time from an NTP server. Sundays light up in red and Christmas Eve in purple.

This appears to be just the thing hackers like [vk2zay] could use for inspiration during their sort-of-annual Advent Calendar of Circuits wherein a different circuit is made each day leading up to Christmas.