It’s not Halloween yet, but if you’re planning a technically-complicated costume, it might serve you well to start building now. To that end, here’s a guide from [Ikkalebob] on how to produce a compact animatronic eye mechanism.
The eye is inspired by mechanisms used in professional animatronics. However, that doesn’t mean it’s hard to build. Complex machining is done away with in favor of readily reproducible 3D-printed components. The eyes are able to look in different directions and can move realistically, and the build includes working eyelids that have a great blinking action to them that feels very natural. An Arduino Uno is charged with running the eyes, paired with a bunch of hobby servos and an Adafruit PCA9685 servo driver. A hefty 5V, 4 amp power supply is on hand to deliver enough juice so the servos move smoothly without stuttering.
The program is known as TwinkleFOX, and relies on the popular FastLED library for addressable LEDs. [Mark’s] demo setup is built around using WS2811 LEDs, put together in a string with plastic diffusers on each bulb. The Arduino is programmed to vary the brightness of each LED according to a triangle wave function. To create the twinkling effect, each LED has its own unique clock signal, so they vary in brightness at different times and at different rates.
Using an Arduino Uno or Leonardo, [Mark] reports its possible to twinkle 300 individual LEDs at a rate of over 50 updates a second. Using a faster microcontroller should net reliable performance with longer strings. Meanwhile, if you’re wondering how the older-style lights used to twinkle, we’ve covered that before too. Video after the break.
The project works in a relatively simple fashion: essentially, a Raspberry Pi Pico is charged with reading an HC-SR04 ultrasonic rangefinder. It’s all wrapped up in a 3D-printed skull-like housing. When the skeleton detects someone or something close in front, the Pi triggers a small servo hooked up to a 3D-printed gear. This interfaces with a pair of racks which drive the skull’s eyebrows up and down, and opens and shuts its jaw.
Of course, there are some major anatomical problems here. Skulls don’t have eyebrows; that’s just not possible. Eyebrows are hair attached to flesh and muscle; they simply don’t exist in the world of bone. However, it’s fair to say [Kevin]’s taking creative license for the sake of the holiday, and we can all support that.
This is a basic build, and a fun one. It would be an excellent way to learn some basic microcontroller skills, while also serving as a great little Halloween charm to scare guests going back to the fridge for another beverage.
We get a cavalcade of quality holiday hacks every year around this time. This year should be no exception – so get your spooktacular hacks into the tips line, post-haste! Video after the break.
During the day, or simply when it’s bright inside, the mirror appears normal, like any other. However, behind the special two-way mirrored glass surface is a spooky 3D print, such as a skull or an annoying yellow cartoon character. When the lighting level gets low, everything changes. A light-dependent resistor hooked up to a Digispark detects the change, and then fires up some 5V LEDs to light the scary image, revealing it behind the mirror. Even better, it plays a loud screaming sound with the help of a DFplayer MP3 module.
We’d love to see the concept taken even further, too. It would be quite something if, when a passer-by approached, the room lights suddenly cut out and the mirror activated in its full glory.
We’ve seen some great Halloween builds over the years. If you’re eager to get one out this season, you might wanna get hacking now! Video after the break.
The festive season is often as good a reason as any to get out the tools and whip up a fun little project. [Simon] wanted a little tchotchke to give out for the holidays, so they whipped up a Christmas tree PCB that’s actually Arduino-compatible.
It’s a forward-looking project, complete with USB-C connector, future-proofing it for some time until yet another connector standard comes along. When plugged in, like many similar projects, it blinks some APA102 LEDs in a festive way. The PCB joins in on the fun, with white silkscreen baubles augmented by golden ones created by gaps in the soldermask.
An ATTiny167 is the brains of the operation, using the Micronucleus bootloader in a similar configuration to the DigiSpark Pro development board. It relies on a bit-banged low-speed USB interface for programming, but the functionality is largely transparent to the end user. It can readily be programmed from within the Arduino IDE.
It’s not an advanced project by any means, but is a cute giveaway piece which can make a good impression in much the same way as a fancy PCB business card. It could also serve as an easy tool for introducing new makers to working with addressable LEDs. Meanwhile, if you’ve been cooking up your own holiday projects in the lab, don’t hesitate to drop us a line!
The trick here is in the delivery. [MG] has produced a large quantity of these small devices, packaging them in anti-static wrappers. The wrappers contain a note instructing children to insert them into their parent’s work computers to access “game codes”, and to share them with their friends while hiding them from adults.
The idea of children brazenly plugging hostile USB devices into important computers is enough to make any IT manager’s head spin, though we suspect [MG] doesn’t actually intend to deploy these devices in anger. It serves as a great warning about the potential danger of such an attack, however. Stay sharp, and keep your office door locked this October 31st!
It’s a simple build that demonstrates the basic techniques of working with DACs and scopes in a charming holiday fashion. A Tektronix T932A analog oscilloscope is pressed into service as a display, by operating in XY mode. A Teensy 3.5 was then chosen for its onboard digital to analog converters, and used to output signals to draw a Christmas tree and star on the screen.
Old-school coders will appreciate the effort taken to plot the graphics out on graph paper. While the hack doesn’t do anything cutting edge or wild, it’s impressive how quick and easy this is thanks to modern development methods. While the technology to do this has existed for decades, a hacker in 1998 would have spent hours breadboarding a PIC microcontroller with DACs, let alone the coding required. We’ve come a long way.