Sims-Style Plumb Bob Broadcasts Your Mood

November 28, 2020 by Kristina Panos 3 Comments

While there are a lot of objects from the Sims that we wish were real, we probably wish more than anything that everyone had a mood indicator hovering above their heads at all times. It would make working from home go a lot more smoothly, for instance. [8BitsAndAByte] made this Bluetooth-controlled plumb bob as part of their Sims Halloween costume, but we think it has real day-to-day value as this pandemic wears on, either as a mood ring or a portable free/busy indicator.

The hardware is about as simple as it gets — an Adafruit Feather nRF52 Bluefruit controls a pair of NeoPixel rings, one for each half of the translucent 3D-printed plumb bob. Power comes from a 500mAh battery, and all the electronics are situated inside of an attractive hat. Check out the build video after the break.

There’s more than one way to use color to convey information. This seven-segment temperature display does it with thermochromic film.

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Halloween Pumpkin Scares With An Evil Eye

November 15, 2020 by Lewin Day 1 Comment

These days, a classic Jack O’ Lantern just doesn’t cut the mustard. Kids are expecting to be scared by high-quality animatronics at a minimum. This haunting work by [Zero To Infinity] might just do the trick.

A real pumpkin is pressed into service in this build, with the usual threatening grin and candlelit interior. However, where it differs is in its single, animated eye. The eye itself is constructed of a pingpong ball, drawn upon with markers for a creepy bloodshot look. A pair of servos allow the eye to twitch and roll, under the command of an Arduino Nano. For further interactivity, an ultrasonic sensor is used to only trigger the pumpkin when it senses a person approaching.

It’s a fun holiday build that also serves as a great primer on how to work with servos and microcontrollers. We can imagine a more advanced setup using more sensors and pumpkins to train multiple eyes on the unsuspecting visitor. If that’s not scary enough, perhaps just make your pumpkins breathe fire instead. Video after the break.

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Haunted TV Does Mirror Scares With Raspberry Pi

November 13, 2020 by Lewin Day No comments

Hallowe’en may be over for another year, but that just means you’ve got more time to prepare your build for next time. [gocivici] has a fun twist on the classic mirror scare that might be just up your alley.

The build starts with an old black and white TV, hooked up to a Raspberry Pi 3. The Pi films the scene in front of the television through a camera secreted into the screen’s headphone jack, and displays it on screen. The camera feed is run through OpenCV, which runs face and eye detection algorithms to determine when a person is looking at the screen. Based on a basic timer script, when a viewer has looked long enough, a ghostly apparition is displayed, lurking behind the viewer. When the user looks over their shoulder, the apparition quickly disappears, as per the classical horror trope.

It’s a fun build that would make an excellent set piece for your next Hallowe’en party. For extra effect, be sure to secret it down a dark hallway with some IR LEDs illuminating the scene for the camera only. If you prefer something with a little more whimsy, consider these animated singing pumpkins instead. Video after the break.

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Computer Vision Maps Christmas Lights

November 3, 2020 by Bryan Cockfield 27 Comments

There’s a small but dedicated group of folks out there who spend all year planning their Christmas decorations. These aren’t simple lawn ornaments or displays, either, but have evolved into complex lightning performances that require quite a bit of computer control. For some things, hooking up a relay to a microcontroller can get the job done, but [Andy] has turned to computer vision to solve some of the more time-consuming aspects of these displays.

Specifically, [Andy] has a long string of programmable RGB LED lights to wrap around a Christmas tree, but didn’t want to spend time manually mapping out each light’s location. So he used OpenCV to register the locations of the LEDs from three different camera angles, and then used a Python script to calculate their position in the 3D space. This means that he will easily be able to take the LEDs down at the end of the holidays and string them back up next year without having to do the tedious manual mapping ever again.

While [Andy] notes that he may have spent more time writing the software to map out the LEDs than manually doing it himself, but year-after-year it may save him a lot of time and effort, not to mention the benefits of a challenge like writing this software in the first place. If you want to get started on your own display this year, all you really need is some lights and a MIDI controller.

Raspberry Raven Pi Security Camera Does Double Duty

November 3, 2020 by Kristina Panos 11 Comments

The worst thing about holiday decorations is that while you could leave them up all year, your neighbors probably won’t like you very much for it. Christmas lights on your house are one thing, but as far as Halloween decorations go, [MisterM]’s raven security camera is one of the few exceptions to this rule.

Nevermore will [MisterM] wonder who goes there. As soon as this raven lays its beady red LED eyes on whatever is lurking in the garden, it comes to life with a bit of head swiveling and some random sounds. The bird either goes CAW! or quotes Christopher Lee’s reading of Edgar Allen Poe’s “The Raven”.

Inside this bird’s chest cavity is a Raspberry Pi 2 and standard camera, a servo to swivel the head, and an audio amplifier and speaker. This bird is running MotionEye on top of the Raspi OS so it can run a script whenever it senses motion.

We like that [MisterM] was able to find right-sized bits of plastic to mount the servo in the neck and the horn to the head. It just goes to show that not everything needs a 3D printer, a CNC, or woodworking. Check out the scary demo after the break.

Want to scare the whole neighborhood? Check out the science behind good-looking house projections.

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Animated Pumpkins Sing And Scare On Halloween

October 30, 2020 by Lewin Day 5 Comments

The animated video combined with the 3D-printed prop makes for an excellent effect.

Carving Jack O’ Lanterns out of pumpkins is a favorite Hallowe’en tradition for many, but relying on candles and knives is decidedly low-tech. [Lewis] of [DIY Machines] decided to whip up something a little more animated to scare the local trick-or-treaters instead.

The build consists of 3D printed pumpkins, lit from behind with a low-cost projector. Driven by a Raspberry Pi, the projector plays video files that project animated faces onto the pumpkins. The effect is great, giving the illusion of a real anthropomorphic Jack O’ Lantern sitting on your very porch. To control the system, a series of arcade buttons are hooked up to the Raspberry Pi allowing visitors to activate a song, a scare, or a story.

It’s a fun build that is a great way to add some interactivity to your Hallowe’en decorations. If you want to take your work up a notch, consider projecting on to your whole house. Video after the break.

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Projecting Halloween Peril

October 28, 2020 by Matthew Carlson 3 Comments

Every holiday has a few, dedicated individuals committed to “going all out.” Whether they’re trying to show up the neighbors, love the look, or just want to put a smile on the faces of those passing by; the results are often spectacular. A recent trend in decorations has been away from analog lights and ornaments and towards digital light shows via a projector. [Georgia Clegg] and [Luma Bakery] have written up a fantastic guide detailing the involved process of house projection for those feeling the holiday spirit.

There is more to the effect than simply pointing a projector at a home and running a video clip. The good displays make use of the geometry of the home and the various depths of the walls don’t distort the picture. The house itself is mapped into the image being displayed.

There are generally two approaches to mapping: point of view mapping and neutral/orthographic mapping. The first is just setting the projector in a fixed position and designing the graphics in such a way that they will look correct. The downside is that if there are multiple projectors, each projector will need to be separately designed for and they cannot be moved or adjusted. The second maps the house in an actual 3d sense and figures out how to display the content according to the viewpoint that the projector is currently at. This means you can create one source content and simply export it for the various projectors.

As you can imagine, the second is much more involved and this is where [Georgia Clegg] has stepped in. There’s a whole series that covers creating your house in MeshRoom, cleaning it up in Blender, creating the videos in After Effects, and setting up your projector to keep it running through the season.

We’ve seen other amazing projector mapping displays with lasers here at Hackaday. Now you can make one yourself. Just don’t get bogged down refurbishing your vector projector along the way.
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