UV Monitoring Budgie Keeps An Eye On Exposure Levels

October 19, 2022 by Lewin Day 2 Comments

UV rays are great at helping us generate vitamin D, but they can also be harmful, causing sunburn and even melanoma. To help kids keep track of the UV index in his local area, [Jude Pullen] created the UV Budgie.

The build is based around an Arduino Nano 33 IoT board, which queries the Met Office’s API to determine the UV level in the area. The relevant data is then displayed on a small e-ink display, with cute little sun characters telling you about the prevailing conditions. It also announces the current risk level with recorded voice samples, advising on whether precautions should be taken, such as using sunscreen or sheltering inside for the worst days. Plus, there’s a bird that flaps its wings to announce an update, actuated by a small servo in the base.

It’s a fun build that should help [Jude] and his family remain sun safe in the summer. [Jude] notes the build could also be reprogrammed to share other warnings, too. APIs to query local air quality or radiation levels are just some of the ideas that come to mind. Video after the break.

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Whip Up Some Homemade Artisanal Flux

October 18, 2022 by Al Williams 32 Comments

You don’t think much about the power company until you flip the lights on and they don’t come on. The same can be said of soldering flux. You don’t think much about it, usually, until you try soldering without it. Flux has a cleaning action on metal surfaces that allows for a proper solder joint. The problem is, do you have any idea what’s in the flux you are using? We don’t either. [Catsndogs] has a recipe to make your own flux and then you’ll know.

At the heart of rosin flux is basically tree sap. If you live near pine trees, you can source it naturally. If not, you can find it at music instrument stores. Stringed instruments use rosin, so it is readily available. If you do source it yourself, [Catsndogs] reports that it doesn’t matter if it is old or clean. You do want to pick out as much tree bark and dead ants as you can, though. You essentially dissolve it in alcohol (at least 80% isopropyl or ethanol). Then filter it through filter paper or a coffee filter.

You can adjust the viscosity by allowing the alcohol to evaporate to make the mixture thicker or by adding more alcohol to make it thinner. Thicker flux is good for tacking down SMD parts. As you might expect, this isn’t “no clean” flux. Also, the flux is very flammable, so be careful.

This isn’t the first time we’ve heard of this recipe. Or even the second time. But it is a good reminder that you can make your own free of whatever wacky chemicals are in the commercial preparations.

Automatic Flag Waver Lets You Show Your Loyalty Without Getting Tired

October 16, 2022 by Robin Kearey 31 Comments

A flag is a great tool to show your loyalty to a country, a sports team or even a philosophical movement. But there’s not so much you can actually do with a flag: you can either hang it somewhere, or wave it around to attact others to your cause. [Mellow] found that waving quickly becomes tiresome, and decided to design a machine that automates this task for him.

Now there’s a bit more involved in designing a proper flag-waver than simply moving the flag back and forth. Ideally, the fabric should flow smoothly from side to side and show both sides equally, in the same way a human would do when waving a big flag around. After a bit of research [Mellow] decided on a design that generates a rather complex motion using just a single servo: the mast is tilted from left to right, while gravity ensures the flag rotates around its axis. It’s probably best demonstrated visually, as [Mellow] does in the video embedded below.

The flag-waving mechanism is designed in Fusion 360 and 3D printed using white filament. Inside a little square box is a Wemos D1 Mini, powered by a lithium battery scavenged from a vape pen, as well as a battery management system and a power switch. The servo sits on top of the box and holds the flag in a little socket that allows the mast to rotate freely. [Mellow] also went one step further and built a two-flag waver, which still uses only one servo but creates two opposite motions through a set of spur gears. Both waver types bring a lively atmosphere to their surroundings, and we can actually imagine them being useful in places like sports bars.

Automatic flag-wavers are still rare devices, and as far as we can tell this is only the second one we’ve seen, after this hat-mounted example. That is, if you don’t count the automatic “flag” on this mailbox.

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Enjoy The Beauty Of Corona Discharge With This Kirlian Photography Setup

October 12, 2022 by Dan Maloney 12 Comments

In our age of pervasive digital media, “pics or it didn’t happen” is a common enough cry that most of us will gladly snap a picture of pretty near anything to post online. So if you’re going to take a picture, it may as well be as stunning as these corona discharge photographs made with a homebrew Kirlian photography rig.

We know, Kirlian photography has a whole “woo-woo” vibe to it, associated as it has been with paranormal investigations and the like. But [Hyperspace Pirate] isn’t flogging any of that; in fact, he seems way more interested in the electronics of the setup than anything else. The idea with Kirlian photography is basically to capacitively couple a high-voltage charge across a dielectric, which induces an electrostatic discharge to a grounded object. The result is a beautiful purple discharge, thanks to atmospheric nitrogen, that outlines the object being photographed.

[Pirate]’s first attempt at a Kirlian rig used acrylic as a dielectric, which proved to be susceptible to melting. We found this surprising since we’ve seen [Jay Bowles] successfully use acrylic for his Kirlian setup. Version 2 used glass as a dielectric — right up until he tried to drill a fill port into the glass. (Important safety tip: don’t try to drill holes in tempered glass.) Version 3 used regular glass and a 3D-printed frame to make the Kirlian chamber; filled with saltwater and charged up with a homebrew Tesla coil, the corona discharge proved enough to char fingertips and ignite paper. It also gave some beautiful results, which can be seen starting at around the 7:40 mark in the video below.

We loved the photos, of course, but also appreciated the insights into the effects of inductance on the performance of this setup. And that first homebrew flyback transformer [Hyperspace Pirate] built was pretty cool, too.

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Ugliest Airplane Ever Built Predicted The Future

October 5, 2022 by Al Williams 31 Comments

The airplane that many called “the flying barrel” is also widely considered the ugliest plane ever built. However, [Dark Skies] in the video you can see below argues that the Stipa-Caproni was the direct predecessor of the turbofan engine. Either way, it is an interesting and unique part of aviation history.

The plane was built in the days when inventors were experimenting with many different ways to improve aircraft utility and performance. In this case, the inventor built an “intubated propellor” which used a prop to draw air through a venturi tube in an effort to improve engine efficiency. The 570kg vehicle had a wingspan of just over 14 meters and was a bit more than 6 meters long. It could reach about 72 knots and climb to over 3 km.

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An Automated Digitizer For 35mm Slides

October 3, 2022 by Lewin Day 12 Comments

Slides make for great old-timey fun, but it’s awesome to have a digital backup of your old photos, too. An automatic digitizer can make quick work of your collection, and this build from [rbwood53] will do just that.

The digitizizer is based on a Kodak carousel slide projector. It’s fitted with LED strips instead of the original light source, which are used to illuminate the slides themselves. An Arduino Nano is used to command a camera to take photos, via a hacked-up shutter release remote. The camera is set up with a zoom lens and relies on auto-focus to get crisp, clear images of the slides. The Arduino is also charged with telling the carousel system to advance to the next slide as required. It keeps count as the slides go by, so it stops when the entire carousel has been imaged.

Overall, it’s a straightforward build that automatically imaged over 40 boxes of slides for [rbwood53] without issue. If you’ve got a smaller collection to digitize, you might find this simple 3D-printed adapter to be useful, too!

Homebrew LED Strips That Are HomeKit-Compatible

October 3, 2022 by Lewin Day 6 Comments

Google, Amazon and Apple are all duking it out for supremacy in the smart home space. As you’ve probably noticed, cheaper smart lights and the like typically don’t offer connectivity with Apple’s HomeKit system. However, if you want some smart lighting that works in that ecosystem without breaking the bank, you can always build your own!

This simple build uses an ESP8266-01S as the brains of the operation. It’s a cut-down board that only has two GPIO pins available, but for this job, that’s enough. It’s paired with a simple relay for switching a single-color LED strip on and off, and an MP2307 buck converter for power. The code loaded onto the ESP8266 is simple, and allows it to connect to Wi-Fi and link up with Apple HomeKit for control.

Let’s say you’re a real fancy-pants, though, and you want RGB-addressable LEDs for your HomeKit setup. No problem, you can do that too! It’s as straightforward as hooking up an ESP8266 to some WS2812B LED strip and flashing the right firmware that emulates an Elgato EVE LED strip. You can even activate special lighting effects on the via the EVE app if you so desire, to take advantage of the fully-addressable nature of the strip.

There are plenty of off-the-shelf solutions in this space, but many of them are quite expensive for what you actually get in the box. Sometimes building your own is more fun, too. Alternatively, if you don’t like Apple’s smart home solutions, you can always try a more open alternative. Video after the break.

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