Measuring UV-C For About $5

Looking to sterilize something? Give it a good blast of the old UV-C. Ultraviolet radiation in the shortest wavelength band breaks down DNA and RNA, so it’s a great way to kill off any nasties that are lurking. But how much UV-C are you using? [Akiba] at Hackerfarm has come up with the NukeMeter, a meter that measures the output of their UV-C sterilizer the NukeBox. It is built around a $2.50 sensor and a $3 Arduino.

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It’s Not An Arc Lamp, It’s A Lamp Arc

One wouldn’t expect there to be much to cause envy in the world of desk lamps, after all whether it’s a classic Anglepoise or a dollar store LED affair if it does its job of casting the requisite quantity of light where it’s needed, most of us are happy. But then we saw [Ronny Ziss]’s LED arc desk lamp, and suddenly all other lamps simply aren’t good enough any more. If it’s not a wall-to-wall arc of LEDs spanning the length of the desk, it quite simply no longer cuts the mustard. We’ve entered the world of lamp envy, folks, and it’s a poorly-illuminated place to be.

As you can see in the video below the break both the hardware and the software of this lamp are impressive in their own right, the structure being an aluminium extrusion carrying an addressable white LED strip fitted into an arc between two custom plywood blocks on the walls either side of the desk. The software is controlled through a rotary encoder, and allows command of the position, width, and brightness of the illuminated portion, as well as having a hidden Pong game. Sadly he doesn’t reveal the software or the microcontroller in question, however the task is not an onerous one and it’s likely most Hackaday readers could put it together using their board or processor of choice.

In years of lamp projects on Hackaday, we can’t find another quite like this one. Conventional lamp projects can still be stylish though.

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Thunder Pack Is A Bolt Of Lightning For Wearables

Do you need portable power that packs a punch? Sure you do, especially if you want to light up the night by mummifying yourself with a ton of LED strips. You aren’t limited to that, of course, but it’s what we pictured when we read about [Jeremy]’s Thunder Pack. With four PWM channels at 2.3 A each, why not go nuts? [Jeremy] has already proven the Thunder Pack out by putting it through its paces all week at Burning Man.

Click to embiggen!

After a few iterations, [Jeremy] has landed on the STM32 microcontroller family and is currently working to upgrade to one with enough flash memory to run CircuitPython.

The original version was designed to run on a single 18650 cell, but [Jeremy] now has three boards that support similar but smaller rechargeable cells for projects that don’t need quite as much power.

We love how small and powerful this is, and the dongle hole is a great touch because it opens up options for building it into a wearable. [Jeremy] made a fantastic pinout diagram and has a ton of code examples in the repo. If you want to wade into the waters of wearables, let whimsical wearables wizard [Angela Sheehan] walk you through the waves.

Gyroscopic Wi-Fi LED Die Is Pretty Fly

As cool as sculptural LED cubes are, the only thing you can really do is look at them. They’re not going to stand up to a lot of handling, and as tedious as it is to bend all those leads when building them, you probably wouldn’t want to mess with them anyway.

LED dice on the other hand are robust, blinky playthings with many possibilities, especially if they have a gyroscope and wireless control like the one [moekoe] built. Inside this tiny 25cm³ die is the equally small ESP8285-01F, which lets [moekoe] control the rainbow light show with a Blynk app.

As you will see in the excellent build video that makes this build look challenging instead of impossible, the cube gets permanently sealed up with solder joints. Most but not all of these transfer power, ground, and data around the faces.

Once the cube is together, [moekoe] uses pogo pins to program it, and can charge the little LiPo inside through contact pads. We love the idea of using a cubical printed jig to help solder the PCB edges together, but not as much as we love [moekoe]’s home-brewed SMT soldering setup.

If you want an easier way to make sculptural LED cubes, build yourself a lead-formin’ machine.

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The Corona Clock

Schools are closed here in Germany until after Easter vacation, and that means that our almost-six-year-old son Max is staying at home with us. The good news is that my wife and I work from home anyway, so it’s not too stressful as long as he can look after himself for eight hours per day. The bad news is that there’s no way a kindergarten kid can take care of himself for such long stretches, and we don’t want to just park him in front of the boob tube. At least there’s two of us.

The new stay-at-home life has required some adjustment, but for at least the first five days (and counting) it’s working out pretty darn well. One trick: my wife came up with the idea of a visual schedule to help Max divide his day up into kindergarten-sized chunks, and then we added an LED strip behind it to turn it into a linear clock of sorts. And we did it with stuff we had lying around the house.

Granted, it’s not a super deep hacky-hack, and some of you out there could probably get it done with a handful of 555 timers. But it was quick, gets the job done, and heck, with NTP sync, it’s the most accurate kiddie clock in the world! So those of you out there who are stuck like we are, trying to balance childcare and working from home, here’s a quick project that can increase familial harmony while giving you an excuse to order more LED strips.

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A Smart Controller For Your DIY UV Cure Box

Resin 3D printers are finally cheap enough that peons like us can finally buy them without skipping too many meals, and what means we’re starting to see more and more of them in the hands of hackers. But to get good results you’ll also want a machine to cure the prints with UV light; an added expense compared to more traditional FDM printers. Of course you could always build one yourself to try and save some money.

An earlier prototype build of the interface.

To that end, [sjm4306] is working on a very impressive controller for all your homebrew UV curing needs. The device is designed to work with cheap UV strip lights that can easily be sourced online, and all you need to bring to the table is a suitable enclosure to install them in. Here he’s using a metal paint can with a lid to keep from burning his eyes out, but we imagine the good readers of Hackaday could come up with something slightly more substantial while still taking the necessary precautions to not cook the only set of eyes you’ll ever have.

Of course, the enclosure isn’t what this project is really about. The focus here is on a general purpose controller, and it looks like [sjm4306] has really gone the extra mile with this one. Using a common OLED display module, the controller provides a very concise and professional graphical user interface for setting parameters such as light intensity and cure time. While the part is cooking, there’s even a nice little progress bar which makes it easy to see how much time is left even if you’re across the room.

At this point we’ve seen a number of hacked together UV cure boxes, but many of them skip the controller and just run the lights full time. That’s fine for a quick and dirty build, but we think a controller like this one could help turn a simple hack into a proper tool.

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Powering Neon With A Joule Thief

Joule thief are small, fun circuits which exploit a few characteristics of electronics and LEDs in order to “steal” virtually all of the energy stored in a battery. They can operate at incredibly small voltages and are fairly simple to make. With a few modifications to this basic circuit it’s possible to drive other things than an LED, though, like this joule thief that lights up a neon bulb.

The circuit from [suedbunker] aka [fuselage] is based on a pin from the Chaos Communication Camp which had a standard LED. To get a neon light to illuminate a few modifications to the standard joule thief are needed.

First, the windings have to be changed from 10:10 to 10:80 to increase the voltage across the bulb. Second, a transistor with slightly different characteristics was used than the original design. The capacitor was also replaced with a larger one.

While it might seem simple, the physics of how a joule thief works are anything but, and modifying the delicate circuit to work with something other than an LED is commendable. It also has a steampunk vibe which is a cool look even in projects that don’t involve steam at all.