Ah, Christmas. That wonderful time of year when you can roll out of bed to the screams and wails of children, grab a hot cocoa, and spend several hours arguing with an 8-year-old about which LEGO set to build first. Simply magical. While you’re waiting for the Doctor Who Christmas special to come on, settle down with these wonderful Christmas-themed builds that came in over the last few weeks.

One step closer to Robot Santa

Here’s an interesting way to spice up your seasonal headwear. [Mark] took a Santa hat and added a string of multicolored LEDs to the brim. The lights were picked up at a drug store for a dollar. Control is through a simple push button connected to an ATtiny13. Press the button, the lights cycle in a different pattern. Very cool, so check out the video.

A holographic holiday tree

[Auger] posted this very cool light up Christmas tree decoration on Instructables. This tree is made up of three pieces of acrylic. Different designs were laser cut into each piece of plastic – candy canes for the ‘red’ piece, stars and tinsel for the ‘yellow’ piece, and the tree for the ‘green’ piece. LEDs of the respective colors are cemented to the bottom of each bit of plastic. It’s called light piping and is used everywhere. This is the first time we’ve seen three colors, though.

This is what nerds do, and it’s awesome

[Rickard Dahlstrand] was playing around with his phone trying to take deliberately fuzzy pictures of his tree. He noticed the dashes produced from the LED Christmas lights must be produced from PCM dimming. Going through the EXIF data in the picture, he found the exposure time was 1/17th of a second. 1/17 of a second = ~ 58 ms / 5 (cycles on the picture) = ~11 ms per cycle = ~100 Hz frequency on the PCM dimming. Of course this is just about 2 times the line frequency in [Rickard]‘s native Sweden, so we’ll call this confirmed. There’s no blog post for this, but we’ve never seen a clearer example of applied geekery. Simply awesome.

Yeah, we measured [Rickard] on a nerd meter

In the spirit of giving, [Johannes] decided to tell the entire world exactly how nerdy he is. He built a ‘Nerd Alert’ meter out of an old 1950s Japanese multimeter. The old guts of the meter were chucked, and a simple amp made out of a transistor amplifies the current flowing through the user’s fingers. A neat scale ([Johannes] measures somewhere between Amiga Workbench and Space invaders) replaces the old, boring, number-based one. Again, no write-up, but here’s some awesome build pictures.

Finally a use for all those old radio tubes

[AUTUIN] took apart a vacuum tube with a blow torch and a diamond cutting wheel. Surprisingly, he was able to put it back together, but not before making a wonderful Christmas ornament. There are two copper wires inside the envelope that are the leads to a single orange-red LED. The whole thing is powered by a watch battery. We’ll be sure to reference [AUTUIN] next time we have to take apart a glass bulb, because he managed not to burn, cut or blind himself.

Six things in a links post? It’s a Christmas miracle!

[Darryl] sent in a nice tool to select and display all of the hacker/maker merit badges available from Adafruit. Oh, we’re still trying to figure out who to give 10 badges to. We’re giving away skull ‘n wrench badges to the top ten hacks ever featured here. Leave a note in the comments, or tell us who should win.

Holiday wishes

Now put the computer down and go spend some time with your families, or failing that, strangers. Of course there’s an all day Doctor Who marathon, and that thing isn’t going to watch itself…

Hackaday contributor [Nick Schulze] popped out an impressive set of LED headgear for a hat-themed party.

[Nick] is no stranger to working with LEDs. Previously he built a blue 8x8x8 cube something like this other 512 node full color version. He had a bunch of LEDs left over from that project and decided to put them to good use.

The first part of the build is the frame itself, made from thick fencing wire. He just started bending it around his head and got an uncomfortable head-shaped hoop to which he could solder. From there, enameled copper wire wraps its way through the system, supplying logic levels to all of the LEDs. Everything is done without a circuit board of any kind. The LED drivers themselves are attached by first using a zip tie to affix a resistor to the frame, then by soldering the TLC5916 chip to that resistor. Even the ATmega8 is included dead-bug style by soldering it to the frame which we think servers as ground. Program it with the free-floating female pin header and you’ll get the fantastic animations seen in the video after the break.

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[Lauren] has created a facial conditioning device dubbed the Happiness Hat. The hat measures a sensor at the wearer’s cheek to determine if the wearer is smiling. When the hat does detects the wearer is not smiling, it activates a servo that prods the wearer. This project is fairly unique in that it provides haptic bio-feedback of what the body is doing, a similar project to the Happillow. While the Happiness Hat seems to work for treating the outward symptoms of unhappiness, this is but an early step towards the droud.

Viddy yourself this Halloween standing out amongst your droogs with this Mini-POV bowler. We’ll quit with the nadsat so as to avoid a kick to the yarbles, you have our sincerest appy polly loggy for starting in the first place. [cheeto4493] modified a Mini-POV to sit atop the bowler with an extension hanging out toward the brim that houses the lights. A motor, mounted inside the hat spins the entire device. Some counterweight was necessary to keep the whole thing from wobbling too much.

It is worth noting that, in person, the message scrolls slowly by. The refresh rate on the camera causes it to seem to jump around in the video.