Parts Bin Spooky Eye Build

Halloween is a great holiday for hacks, bringing out the creativity in even the most curmudgeonly wielder of a soldering iron. [tdragger] was looking to have some good old fashioned Halloween fun, and got to thinking – putting together this great Spooky Eyes build in their attic window.

The effect itself is simple – just two glowing orange LEDs spaced the right distance apart, placed in the highest window in the house. As every young child knows, the attic is almost the spookiest room in the house, second only to the basement.

Various effects were programmed in to the Arduino running the show, like breathing and blinking effects, to give that frightful character. For maintenance and programming purposes, [tdragger] wanted to have the Arduino remotely mounted, and searched for a solution. Rather than leaning on a wireless setup or something modern and off-the-shelf, instead some old RJ11 telephone extension cables were pressed into service. These allowed the eyes to be placed in the window, allowing the Arduino to be placed in a more accessible location.

It’s a basic project, but one that has a good fun factor. Sometimes it’s good to use what you’ve got to hand, so that the buzz of enjoyment isn’t dampened by the long wait for shipping. For something bigger, check out this giant staring eyeball.

Taking Halloween to the Next Level with JARVIS

As an avid “Haunt Hacker”, [Steve Koci] knows a thing or two about bringing high-tech to Halloween. Wanting to build a mobile robot that could accompany him to conventions as a demonstration of the sort of animatronic mechanisms and controls he uses, he came up with the idea of JARVIS. The original plan was to make a more traditional robot, but with the addition of an animated skull and some Steampunk-style embellishments, JARVIS is definitely the kind of thing you don’t want to run into on an October night.

Construction of JARVIS started in 2016, after [Steve] saw the Agent 390 tracked robot chassis from ServoCity. With the addition of extra wheels and a custom track, he converted the Agent 390 into a triangular track arrangement which he said he’s had his eye on since “Johnny 5” sported them back in Short Circuit.

There’s a dizzying array of electronics required to make JARVIS move and talk, not least of which is the “Banshee” prop controller. This device is made to simplify the construction of animatronic heads and provides not only organic-looking randomized movement but automatic jaw synchronization. Using a wireless audio connection, [Steve] is able to talk through a speaker mounted on the chest of the robot, while the skull automatically matches its mouth to his speech in real time. Combined with the GoPro in a two-axis gimbal, this allows JARVIS to function as a fairly robust telepresence platform. Much to the delight/horror of those it’s used on.

Getting JARVIS to move requires not only the two beefy motors and a dedicated controller supplied by the Agent 390 platform, but no less than thirteen servos for the head, arms, and grippers. There’s even a linear actuator used to tilt the skull up and down, presumably for terrifying people of various heights and ages. JARVIS even has a pair of Adafruit’s electronic eyes mounted in the skull, as if you thought you would be spared the horror of seeing glowing eyes following you in the dark.

To control all this hardware, [Steve] uses two RC transmitters in conjunction with a smartphone displaying the video feed coming from the GoPro. It takes some serious finger-gymnastics to get JARVIS doing its thing, which [Steve] says he’s still trying to master.

As many projects that have graced these pages can attest to, hackers seem to delight in coming up with new and exciting ways to terrify the young and old alike. Sometimes they can’t even wait until Halloween.

Continue reading “Taking Halloween to the Next Level with JARVIS”

A Perfect Rose, a Stepper, an X-Ray Machine, and Thee

The Day of Compulsory Romance is once more upon us, and in recognition of that fact we submit for your approval an alternative look at one of the symbols of romantic love: an X-ray of a rose.

Normally, diagnostic X-rays are somewhat bland representations of differential densities of the tissues that compose various organs and organ systems, generally rendered in shades of gray. But [Linas K], a physicist with time to kill and access to some cool tools, captured the images in the video below not only in vivid color, but as a movie. The imaging side of the project consists of a low-power X-ray tube normally used for non-clinical applications and a CMOS sensor panel. The second video shows that [Linas] did an impressive upgrade on the X-ray controller, rolling his own from an FPGA. This allowed him to tie in a stepper motor to rotate the rose incrementally while taking images which he stitched together in post.

Watching the interior structure of the flower as it spins is fascinating and romantic in its own right, for certain subsets of romance. And really, who wouldn’t appreciate the work that went into this? But if you don’t have access to X-ray gear, fear not — a lovely Valentine’s gift is only a bottle of ferric chloride away.

Continue reading “A Perfect Rose, a Stepper, an X-Ray Machine, and Thee”

Teardown: What’s Inside a Christmas Laser Projector?

In the world of big-box retail, December 26th is a very special day. The Christmas music playing on the overhead speakers switches back to the family friendly Top 40, the store’s decorations get tossed in the compactor, and everything that’s even remotely related to the holiday is put on steep clearance. No more money to be made on the most commercialized of all holidays, so back to business as usual.

It’s in this narrow corridor of time, between the Great Holiday Unloading and the new spring products coming in, that you can find some fantastic deals on Christmas decorations. Not that long ago, this would hardly be exciting news for the readers of Hackaday. But Christmas lights and decorations have really started pushing the envelope in terms of technology: addressable RGB LED strands, Bluetooth controlled effects, and as of the last couple years, friggin’ lasers.

That’s right, you’ve seen them all over the neighborhood, probably took a few stray beams to the eye, you might even own your own. Laser projectors have been one of the most popular Christmas decorations for the last couple of years, and it’s not hard to see why. Just set the projector up in front of your house, and you’re done. No need to get on a ladder and string lights on the roof when you can just blast some directed energy up there instead.

Given how popular they are, I was surprised to see a lone Home Accents Holiday Multi-Color Light Projector on the clearance rack at Home Depot for around $14 a few days after Christmas. This was a 75% price reduction from normal MSRP, and right in that sweet impulse-buy price range. Let’s see what’s hiding inside!

Continue reading “Teardown: What’s Inside a Christmas Laser Projector?”

LED Tree Brings Gravity to Christmas

Here’s a fun entry into our coin cell challenge. The power source is the actuating force in [Frank]’s blinky LED Christmas tree, which takes advantage of the physical structure of coin cells and our old pal gravity to roll out some holiday cheer. Talk about forward voltage!

We love the concept, and the circuit couldn’t be more simple. A coin cell is released at the top of the tree and rolls down a series of angled foam board railings covered with 1/4″ copper tape. As the coin cell travels, the negative terminal shimmies along the face of the tree, which has corresponding ground rail tapes. There’s no microcontroller here—all that’s needed for blinks are breaks in the negative rail tape.

The challenging part of a project like this is the execution. Getting a coin cell to ride the rails without falling off required angle experimentation prior to and during the build. Now that it’s done, keeping the tree tilted back against the wall is key. [Frank] explored several options for returning the coin cell to the top using a camera motor and the gear assembly from an old inkjet, but for now, his six-year-old does the job without complaint. Check out his work ethic after the break.

Continue reading “LED Tree Brings Gravity to Christmas”

The Secret of Twinkling Christmas Lights

With the holidays over, many of us are braving the elements to take down all those holiday lights. LED lights have largely taken over the market, but in some places, you can still get classic incandescent bulbs. There are some effects that LEDs can’t quite mimic yet. One of those is the magic of “twinkling” light sets, which [Alec Watson] explains in a Technology Connections video. Everyone has seen bulbs that flash, and strings that dim. But the twinkle effect until recently has been hard to describe.

Typical flashing bulbs use a bimetallic strip. As the filament of the bulb heats up, the strip bends, opening the circuit. Then the strip cools and closes the circuit again. Twinkling lights do exactly the opposite. The bimetallic strip shorts the bulb out rather than open the circuit. Twinkling sets also use a lot of bimetallic strip bulbs – typically every fifth bulb has a strip. The result of the bulbs being shorted out is that all be the bulbs in set see a higher voltage. This makes the entire strip shimmer in time with the flashing. That’s where the twinkling magic comes from.

It occurs to us that the voltage on the strip would be a great source of random seeds. Sure, you’d have to replace bulbs now and again, but how many people can say they get their random numbers from a set of Christmas lights?

If you’re curious how incandescent Christmas lights can blow and not take out the whole strip, check out this article about anti-fuses.

Continue reading “The Secret of Twinkling Christmas Lights”

Custom PCB Revives a Vintage Tree Stand

After 56 years, [Jeff Cotten]’s rotating Christmas tree stand had decided enough was enough. While its sturdy cast aluminum frame was ready for another half-century of merriment, the internal mechanism that sent power up through the rotating base had failed and started tripping the circuit breaker. The problem itself seemed easy enough to fix, but the nearly 60 year old failed component was naturally unobtanium.

But with the help of his local makerspace, he was able to manufacture a replacement. It’s not exactly the same as the original part, and he may not get another 56 years out of it, but it worked for this season at least so that’s a win in our books.

The mechanism inside the stand is fairly simple: two metal “wipes” make contact with concentric circle traces on a round PCB. Unfortunately, over the years the stand warped a bit and the wipe made contact with the PCB where it wasn’t intended do. This caused an arc, destroying the PCB.

The first step in recreating the PCB was measuring the wipes and the distance between them. This allowed [Jeff] to determine how thick the traces needed to be, and how much space should be between them. He was then able to take that data and plug it into Inkscape to come up with a design for his replacement board.

To make the PCB itself, he first coated a piece of copper clad board with black spray paint. Using the laser cutter at the makerspace, he was then able to blast away the paint, leaving behind the two concentric circles. A quick dip in acid, a bit of polishing with toothpaste, and he had a replacement board that was close enough to bolt up in place of the original hardware.

If you’d like to see the kind of hacks that take place above the stand, we’ve got plenty to get you inspired before next Christmas.