The Corona Clock

March 19, 2020 by Elliot Williams 19 Comments

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

March 17, 2020 by Tom Nardi No comments

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

March 14, 2020 by Bryan Cockfield 10 Comments

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.

LED Shirt Does It With Tulle

March 13, 2020 by Lewin Day 13 Comments

Given that we are living in what most of humanity would now call “the future”, we really ought to start acting like it. We’re doing okay on the electric cars, but sartorially we’ve got some ground to make up. Helping with this effort is [Amy Goodchild], who put together a fancy LED shirt for all occasions.

The basis of the shirt is an ESP8266 running the FastLED library, hooked up to strings of WS2812B LEDs. It’s a great combination for doing quick and simple colorful animations without a lot of fuss. The LED strips are then fastened to the shirt by sewing them on, with heatshrink added to the strips to give the thread something to attach to. Tulle fabric is used as a diffuser, hiding the strips when they’re off and providing a more pleasant glowing effect. Everything is controlled from a small box, fitted with an arcade button and 7-segment display.

It’s a fun piece that’s readily achievable for the novice maker, and a great way to learn about LEDs and sewing. We’ve seen other similar builds before, such as this glowing LED skirt. Video after the break.

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A Stylish Coffee Table Featuring Conway’s Game Of Life

March 10, 2020 by Lewin Day 11 Comments

Coffee tables are a great place to put your hot beverages, but most don’t offer a lot beyond that. For most people this is perfectly acceptable, but hackers often desire a little more. [Andrei Erdei] is one such person, who built Conway’s Game of Life into this handsome piece of furniture.

The build began with an existing coffee table, chosen for its glass top. Unfortunately, the top was painted black on one side, and was completely opaque, negating its use as a diffuser for LEDs. Instead, this was replaced with smoked glass, with frosted window film applied to make the final piece darker. This attention to detail allowed [Andrei] to install the WS2812B LED strips underneath such that they’re invisible when switched off. The LEDs themselves are run by a WEMOS D1 mini, based on the ESP8266. This microcontroller has plenty of grunt, which makes running the LEDs and the Game of Life code a cinch.

If you want to make something attractive and blinky, it’s hard to go wrong with Conway’s Game of Life. You can even use it to make a clock or a synthesizer; or build an entire game of Tetris within it. Video after the break.

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Lighting Up A Tiny Train Needs Tiny Tools

March 4, 2020 by Donald Papp 11 Comments

A tiny toy train that [voidnill] illuminated with a small LED strip fragment demonstrates several challenges that come with both modifying existing products, and working with small things in general. One is that it is hard in general to work around existing design choices and materials when modifying something. The second is that problems are magnified with everything is so small.

[voidnill]’s plentiful photos illustrate everything from drilling out small rivets and tapping the holes for screws to installing a tiny switch, LED strip, and button cells as a power supply. When things are so small, some of the usual solutions don’t apply. For example, cyanoacrylate glue may seem like a good idea for mounting small plastic parts, but CA glue easily wicks into components like the tiny power switch and gums up the insides, rendering it useless.

[voidnill] uses lots of careful cutting and patience to get everything done, and demonstrates the importance of quality tools. The LED strip fragment is driven by three small button cells, and while tape does a serviceable job as a battery holder, [voidnill] believes a 3D printed custom frame for the cells would really do the trick.

The kind of work that goes into making or modifying small things really puts into perspective the amount of effort behind projects like this coffee table with an N-gauge model railway inside it.

Using IR LEDs To Hide In Plain Sight

February 28, 2020 by Sharon Lin 90 Comments

Getting by without falling under the gaze of surveillance cameras doesn’t seem possible nowadays – from malls to street corners, it’s getting more common for organizations to use surveillance cameras to keep patrons in check. While the freedom of assembly is considered a basic human right in documents such as the US Condition and the Universal Declaration of Human Rights, it is not a right that is respected everywhere in the world. Often times, governments enforcing order will identify individuals using image recognition programs, preventing them from assembling or demonstrating against their government.

Freedom Shield built by engineer [Nick Bild] is an attempt at breaking away from the status quo and giving people a choice on whether they want to be seen or not. The spectrum of radiation visible to humans maxes out around 740nm, allowing the IR waves to remain undetected by normal observers.

The project uses 940nm infrared (IR) LEDs embedded in clothes to overwhelm photo diodes in IR-sensitive cameras used for surveillance. Since the wavelength of the lights are not visible to humans, they don’t obstruct normal behavior, making it an ideal way to hide in plain sight. Of course, using SMD LEDs rather than the larger sizes would also help with making the lights even less visible to the naked eye.

The result doesn’t perfectly obscure your face from cameras, but for a proof-of-concept it’s certainly a example of how to avoid being tracked.

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