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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Building A Poketch Powered By An Apple Watch

October 2, 2022 by Lewin Day 2 Comments

In Pokemon Diamond and Pearl and the ensuing modern re-releases, the player is given a computer called a Poketch to assist on their journey. [DistressedOwl] decided to build one for real.

The build starts with an Apple Watch, which provides a capable smartwatch platform and a quality display. It’s then given a snap-on case that’s 3D printed in PLA. [DistressedOwl] decided to use model painting techniques to give the build a worn-in, distressed look, which feels fitting for a watch belonging to a rough-and-tumble Pokemon trainer.

The Apple Watch runs a custom app via Test Flight which mimics the appearance of the in-game Poketch. It includes various screens like a basic map and Pikachu looking melancholy next to a digital watch. Sadly, the dowsing app in the Poketch won’t help you find hidden items on the ground.

It’s a build that reminds us of some great Pip-Boy builds over the years. It would make the perfect addition to a Pokemon cosplay, too. Just don’t forget to take some Pokeballs along too!

Teensy Becomes Tiny Handheld Computer, Plays Emulators

September 29, 2022 by Lewin Day 13 Comments

Science fiction predicted that we would one day all carry around tiny computers of great power. While smartphones are great, those predictions were more based on cuter systems that more closely approximated existing computers, with keyboards and screens. [Jean-Marc Harvengt] has built something along those very lines, and it’s called the T-COMPUTER.

This build centers around the mighty Teensy 4.1. That means it’s got an 800 MHz Cortex-M7 processor, 1 MB of RAM, and 8 MB of flash – eclipsing the specs of many retrocomputers of yesteryear. [Jean-MarcHarvengt] has paired the Teensy with a 42-key keyboard and a TFT screen, making a compact handheld computer platform. It’s also got VGA out for display on a bigger screen, along with USB and an old-school Atari joystick port! Power is via a small rechargeable lithium cell on the back, and 16-bit stereo audio is available via a standard 3.5mm jack. There’s also a little GPIO available if you need to interface with something.

It’s capable of emulating the Commodore 64 and Super Nintendo, as well as more obscure systems like the Atari Lynx. And before you ask – yes, it can run DOOM. It’s a fun little platform that would be enjoyable for retrogaming and hacking on the go. If you want to build your own, files are readily available on Github to recreate the system.

Handheld computer builds are always growing in popularity now that so much computing power can be had in a tiny devboard formats. If you’ve built your own neat little rig, be sure to let us know! Video after the break.

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