Old CDs Create A Haunting Rainbow Vortex

The 1960s were, in Western culture, a time of great social and political upheaval, and the dawning of the psychedelia subculture. This resulted in an art style consisting of bright colours in wild, shifting designs. [Afraser-kruck] has built a device capable of generating beautiful rainbow light patterns, which he calls Mesmer-Eyes.

Unnerving, to say the least.

The device uses two CDs, stripped of their reflective coating. This leaves the plastic layer behind, which appears to be acting as a circular diffraction grating. By passing light from a flashlight through a CD, a dazzling rainbow vortex is created, and the effect is even further improved by adding a second disc. The patterns can be moved and shifted by changing the distance between the discs themselves, as well as the flashlight. This is achieved through the use of a sled that slides on PVC pipes, holding each individual element.

It’s a build of a kind we haven’t seen before, and is put to good use as a creepy Halloween decoration, imitating the famous Cheshire Cat. It’s one we can’t wait to tackle ourselves, and we wonder how difficult it would be to turn it into a projection, or a larger scale design.

Creepy eyes remain a Halloween staple; we’ve featured them before. Video after the break.

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What Can You Learn From An Eggbot?

An eggbot is probably the easiest introduction to CNC machines that you could possibly hope for, at least in terms of the physical build. But at the same time, an eggbot can let you get your hands dirty with all of the concepts, firmware, and the toolchain that you’d need to take your CNC game to the next level, whatever that’s going to be. So if you’ve been wanting to make any kind of machine where stepper motors move, cut, trace, display, or simply whirl around, you can get a gentle introduction on the cheap with an eggbot.

Did we mention Easter? It’s apparently this weekend. Seasonal projects are the worst for the procrastinator. If you wait until the 31st to start working on your mega-awesome New Year’s Dropping Laser Ball-o-tron 3000, it’s not going to get done by midnight. Or so I’ve heard. And we’re certainly not helping by posting this tutorial so late in the season. Sorry about that. On the other hand, if you start now, you’ll have the world’s most fine-tuned eggbot for 2020. Procrastinate tomorrow!

I had two main goals with this project: getting it done quickly and getting it done easily. That was my best shot at getting it done at all. Secondary goals included making awesome designs, learning some new software toolchains, and doing the whole thing on the cheap. I succeeded on all counts, and that’s why I’m here encouraging you to build one for yourself.

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Schrödinger Quantum Percolator Makes Half Decent Coffee

I couldn’t decide between normal and decaffeinated coffee. So to eliminate delays in my morning routine, and decision fatigue,  I’ve designed the Schrödinger Quantum Percolator — making the state of my coffee formally undecidable until I drink it.

At its core, the Quantum Percolator contains a novel quantum event detector that uses electron tunneling to determine whether to use caffeinated or decaffeinated coffee. The mechanical components are enclosed in an opaque box, so I can’t tell which type of coffee is being used.

The result is coffee that simultaneously contains and does not contain caffeine – at least until you collapse the caffeination probability waveform by drinking it. As the expression goes, you can’t have your quantum superposition of states and drink it too!

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WiFi Makes The Heart Glow Fonder

It’s more than a little too late for Valentine’s Day this year, but if you start now, you’re sure to be looking good next February. Print something that truly conveys how you feel, through the magic of wireless communication and RGB LEDs (Youtube, French).

Yes, [Heliox] has built a Valentine’s day project, and the presentation is top notch as always. A heart is 3D printed in white filament, with two chambers separated by a thick wall. Each chamber features five NeoPixel LEDs, controlled by an ESP8266 in the base.  The color of each chamber can be controlled through the Blynk smartphone app, allowing you to choose the exact colors that best represent your relationship.

The 3D printed heart does a good job of diffusing the LEDs, with the device showing a rich and consistent glow without any unattractive hotspots. It’s a fun holiday build, and if you’re quick, you might just have time to print one yourself if you start right away.

[Heliox] has good form when it comes to LED projects – her infinity cube is particularly impressive. Video after the break.

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Teardown: AppLights Personalized Projection

Listen, it hurts to hear, but somebody needs to say it. It’s over, OK? You’ve got to admit it and move on. Sure, you could get away with it for a week or two in January, but now it’s just getting weird. No matter how hard you fight it, the facts are the facts: the holidays are over. It’s time to pack up all those lights and decorations before the neighbors really start talking.

Fun Fact: It can’t actually do this

But don’t worry, because there’s an upside. Retailers are now gearing up for their next big selling season, which means right now clearance racks the world over are likely to be playing home to holiday lights and decor. That wouldn’t have been very interesting to the average hacker or maker a few years ago, after all, there’s only so much you can do with a string of twinkle lights. But today, holiday decorations are dripping with the sort of high-tech features you’d expect from gadgets that are actively aiming to be obsolete within the next ten months or so.

Case in point, the “AppLights Personalized Projection” which I found sulking around the clearance section of the Home Depot a couple weeks back. This device advertises the ability to project multi-color custom messages and animations on your wall, and is configured over Bluetooth with a companion application on your Android or iOS device. At a minimum we can assume the device must contain a fairly powerful RGB LED, an LCD to shine the light through, and some sort of Bluetooth-compatible microcontroller. For $20 USD, I thought it was worth taking a shot on.

Around this time last year, the regular Hackaday reader may recall I did a teardown for a Christmas laser projector. Inside we found red, green, and blue lasers of considerable power, as well as all the optics and support hardware to get them running. It was a veritable laser playground for $14. Let’s see if the AppLights projector turns out to be a similar electronic cornucopia, and whether or not we’ve got a new Hackaday Holiday tradition on our hands.

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Printing Christmas Cards The Hard Way

Printing customized Christmas cards is a trivial matter today: choose a photo, apply a stock background or border, add the desired text, and click a few buttons. Your colorful cards arrive in a few days. It may be the easiest way, but it’s definitely no where near as cool as the process [linotype] used this season. (Editor’s note: skip the Imgur link and go straight for the source!)

The first task was to create some large type for the year. [linotype] laser printed “2018” then used an iron to transfer toner to the end of a piece of scrap maple flooring. Carving the numbers in relief yielded ready-to-go type, since the ironing process took care of the necessary mirroring step. The wood block was then cut to “type high” (0.918 inches; who knew?) using a compositor’s table saw – with scales graduated in picas, of course.

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Automate Your Home From The Clearance Rack

The month or so after the holidays have always been a great time to pick up some interesting gadgets on steep clearance, but with decorations and lights becoming increasingly complex over the last few years, the “Christmas Clearance” rack is an absolute must see for enterprising hackers. You might just luck out like [ModernHam] and find a couple packs of these dirt cheap wireless light controllers, which can fairly easily be hacked into the start of a home automation system with little more than the Raspberry Pi and a short length of wire.

In the video after the break, [ModernHam] walks the viewer through the start to finish process of commanding these cheap remote plugs. Starting with finding which frequencies the remotes use thanks to the FCC database and ending with using cron to schedule the transmission of control signals from the Pi, his video really is a wealth of information. Even if you don’t have this particular model of remote plug, or don’t necessarily want to setup a home automation system, there’s probably some element of this video that you could still adapt to your own projects.

The first step of the process is figuring out how the remote is communicating to the plugs. [ModernHam] noticed there was no frequency listed on the devices, but using their FCC IDs he was able to find the relevant information. In the United States, devices like these must have their FCC IDs visible (though they could be behind a battery door) by law, so the searchable database is an invaluable tool to do some basic reconnaissance on a poorly documented gadget.

An RTL-SDR receiver is then used to fine tune the information gleaned from the FCC filing. [ModernHam] found that the signals for all four of the remote plugs were being broadcast on the same frequency, which makes controlling them all the easier. Using the rtl-sdr command, he was able to capture the various signals from the transmitter and save them to separate files. Then it’s just a matter of replaying the appropriate file to get the plugs to do your bidding.

Of course, the RTL-SDR can’t transmit so you’ll have to leave your dongle behind for this last step. Luckily all you need to transmit is the rpitx package created by [F5OEO], along with a supported Raspberry Pi and a small length of wire attached to the appropriate GPIO pin. This package contains the tool sendiq which can be used to replay the raw captures made in the previous step. With some scripting, it’s fairly straightforward to automate these transmissions to control the remote plugs however you wish from the Pi.

The RTL-SDR Blog put together their own guide for “brute forcing” simple remote control devices like this as well, and we’ve even seen similar techniques used against automotive key fobs in the past. Amazing what a piece of wire and some clever code can pull off.

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