Making A Birthday Party Magical With Smart Wands

Visitors to the Wizarding World of Harry Potter at Universal Studios are able to cast “spells” by waving special interactive wands in the air. Hackers like us understand that there must be some unknown machinations happening behind the scenes to detect how the wands are moving, but for the kids wielding them, it might as well be real magic. So when his son asked to have a Harry Potter themed birthday party, [Adam Thole] decided to try recreating the system used at Universal Studios in his own home.

Components used in the IR streaming camera

The basic idea is that each wand has a reflector in the tip, which coupled with strong IR illumination makes them glow on camera. This allows for easy gesture recognition using computer vision techniques, all without any active components in the wand itself.

[Adam] notes that you can actually buy the official interactive wands from the Universal Studios online store, and they’d even work with his system, but at $50 USD each they were too expensive to distribute to the guests at the birthday party. His solution was to simply 3D print the wands and put a bit of white prismatic reflective tape on the ends.

With the wands out of the way, he turned his attention to the IR imaging side of the system. His final design is a very impressive 3D printed unit which includes four IR illuminators, a Raspberry Pi Zero with the NoIR camera module. [Adam] notes that his software setup specifically locks the camera at 41 FPS, as that triggers it to use a reduced field of view by essentially “zooming in” on the image. If you don’t request a FPS higher than 40, the camera will deliver a wider image which didn’t have any advantage in this particular project.

The last part of the project was taking the video stream from his IR camera and processing it to detect the bright glow of a wand’s tip. For each frame of the video the background is first removed and then any remaining pixel that doesn’t exceed a set brightness level if ignored. The end result is an isolated point of light representing the tip of the wand, which can be fed into Open CV’s optical flow function to show [Adam] what shape the user was trying to make. From there, his software just needs to match the shape with one of the stock “spells”, and execute the appropriate function (such as changing the color of the lights in the room) with Home Assistant.

Overall, it’s an exceptionally well designed system considering the goal was simply to entertain a group of children for a few hours. We almost feel bad for the other parents in the neighborhood; it’s going to take more than a piñata to impress these kids after [Adam] had them conjuring the Dark Arts at his son’s party.

It turns out there’s considerable overlap between hacker types and those who would like to have magic powers (go figure). [Jennifer Wang] presented her IMU-based magic wand research at the 2018 Hackaday Superconference, and in the past we’ve even seen other wand controlled light systems. If you go all the way back to 2009, we even saw some Disney-funded research into interactive wand attractions for their parks, which seems particularly prescient today.

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Portable Pi Power Pack Makes For Petite Projects

Since the Pi Zero was released, there have been many attempts to add a power bank. Cell phone batteries are about the same size as a Pi Zero, after all, and adding a USB charging port and soldering a few wires to a Pi is easy. The PiSugar is perhaps the cutest battery pack we’ve seen for the Pi Zero, and it comes in a variety of Hats compatible with the Pi, capable of becoming a small display, a keyboard, or any other thing where a small, portable Linux machine is useful.

The core of this build is a small circuit board the size of a Pi Zero. Attached to this board is a 900mAh battery, and the entire assembly is attached to the Pi Zero with a set of two spring clips that match up with with a pair of pads on the back of the Pi. Screw both of these boards together, and you have a perfect, cableless solution to adding power to a Pi Zero.

But the PiSugar doesn’t stop there. There are also cases, for a 1.3 inch LCD top, a 2.13 inch ePaper display, an OLED display, a camera, a 4G module, and something that just presents the pins from the Pi GPIO header. This is an entire platform, and if you print these parts in white plastic, they look like tiny little sugar cubes filled to the brim with electronics and Linux goodness.

Yes, you’ve seen 3D printed Pi cases before, but nothing in the way of an entire platform that gives you a Pi Zero in an extensible platform that can fit in your pocket and looks like sweet, sweet cubes of sucrose.

The Easiest Thermal Camera Build You’ll Ever See

Thermal cameras are one of those tools that we all want, but just can’t justify actually buying. You don’t really know what you would do with one, and when even the cheap ones are a couple hundred dollars, it’s a bit out of the impulse buy territory. So you just keeping waiting and hoping that eventually they’ll drop to the price that you can actually own one yourself.

Well, today might be the day you were waiting for. While it might not be the prettiest build, we think you’ll agree it can’t get much easier than what [vvkuryshev] has put together. His build only has two components: a Raspberry Pi and a thermal camera module he picked up online for about $80 USD. There isn’t even any wiring involved, the camera fits right on the Pi’s GPIO header.

Of course, you probably wouldn’t be seeing this on Hackaday if all he had to do was just buy a module and solder it to the Pi’s header. As with most cheap imported gadgets, the GY-MCU90640 module that [vvkuryshev] bought came with some crusty Windows software which wasn’t going to do him much good on the Raspberry Pi. But after going back and forth a bit with the seller, he was able to get some documentation for the device that put him on the right track to writing a Python script which got it working under Linux.

The surprisingly simple Python script reads a frame from the camera four times a second over serial and run it through OpenCV. It even adds some useful data like the minimum and maximum temperatures in the frame to the top of the image. Normally the script would output to the Pi’s primary display, but if you want to use it remotely, [vvkuryshev] says he’s had pretty good luck running it over VNC. In fact, he says that with a VNC application on your phone you could even use this setup on the go, though the setup is a bit awkward for that in its current incarnation.

This isn’t the first DIY thermal camera build we’ve seen, and it isn’t even the first one we’ve seen that leveraged a commercially available imaging module. But short of buying a turn-key camera, we don’t see how it could get any easier to add heat vision to your bag of tricks.

A Raspberry Pi Grimoire For The Command Line Wizard

Who says there’s no such thing as magic? Not anyone who knows what a Unix pipe is, that’s for sure. If you do some of your best incantations at a blinking cursor, this scratch-built Raspberry Pi Zero “Spellbook” laptop created by [Calvin] might be just what the apothecary ordered. Lucky for us, he was kind enough to document the design and construction of this penguin-powered tome for anyone else who wishes to dabble in the GNU Dark Arts.

In the series of videos after the break, viewers have the opportunity to watch a project go from idea to final product. The first video was uploaded nearly a month before the project was completed, and goes over some of the design elements of the project as well as different ideas [Calvin] had in terms of things like component placement. Throughout the video, he illustrates his ideas in TinkerCAD, which might not have been our first choice for a project this complex, but it does go to show what’s possible in the free web-based CAD package.

By the second video, [Calvin] has printed some parts and now has the hardware coming together. The general idea is that the outside panels of the “book” are made out of steel cut from the side panel of an old computer, with the 3D printed components taking the form of spacers between the electronic components. These plastic “pages” are not only easier and faster to print than a complete case, but help sell the appearance of the book when viewed from the sides.

[Calvin] has shared his TinkerCAD design so that others can print out the necessary components for the book, though you’ll have to source your own steel plates. He also breaks down all the principle components he used and gives links to where you can buy them, from the display and keyboard down to the screws and standoffs. He went with the Pi Zero and sticks to mainly console work, but if you want something with enough power to throw around a graphical environment, he says there’s room in the case for a Pi 3.

Hackers seem to enjoy hiding hardware inside of books, PLA or otherwise. We’ve recently seen an iPad nestled snugly into a notebook, and of course no house would be complete without a book doubling as a hidden switch.

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Raspberry Pi Powers This Retro Chess Computer

If you imagine somebody playing chess against the computer, you’ll likely be visualizing them staring at their monitor in deep thought, mouse in hand, ready to drag their digital pawn into play. That might be accurate for the folks who dabble in the occasional match during their break, but for the real chess aficionados nothing beats playing on a real board with real pieces. Of course, the tricky part is explaining the whole corporeal thing to a piece of software on your computer.

Enter the “Chess Challenger” by [slash/byte]. Modeled after a commercial gadget of the same name from 1978, his retro-themed open hardware design utilizes the Raspberry Pi Zero and modern chess software to bring the vintage concept into the 21st century. With the Chess Challenger and a standard board, the player can face off in an epic battle of wits against the computer without risk of developing carpal tunnel. We can’t guarantee though that a few boards might not get flipped over in frustration.

The pocket sized chess computer uses a “sandwich” style construction which shows off the internals while still keeping things reasonably protected. All of the electronics are housed on the center custom PCB which features a HT16K33 driver for the dual LTP-3784E “starburst” LED displays, a MCP1642B voltage regulator, 16 TL3305 tactile switches for the keyboard, and a MCP73871 battery management chip for the 3.7 volt lithium-ion battery that powers the whole show. The Pi Zero itself connects to the board by way of the GPIO header, and is mechanically supported by the standoffs used to hold the device together.

On the software side of things, the Pi is running the mature Stockfish open source chess engine. In development now for over a decade, this GPL licensed package aims to deliver a world-class chess gameplay on everything from smartphones to desktop computers, and we’ve seen it pop up in a number of projects over the years. [slash/byte] has provided a ready to flash SD card image for the Raspberry Pi, and even provides detailed installation and setup instructions which guide you through some of the more thorny aspects of the setup such as getting the Pi running from a read-only operating system so that abrupt power cuts don’t clobber the filesystem.

Over the years, some of the most impressive projects we’ve seen revolved around playing chess, and this latest entry by [slash/byte] is no exception. Another example of the lengths the chess community will go to perfect the Game of Kings.

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2600-Inspired Handheld Brings the Faux Woodgrain

The Atari 2600 is a console from a very different time, when home appliances, furniture, and even automobiles were all covered in fake vinyl woodgrain veneer. Somehow it was the in thing for a decade, and then immediately became tacky overnight. Regardless, if you want to evoke the era, that’s what you do – and that’s exactly what [Christian] did with this handheld RetroPie build.

An early concept sketch shows off [Christian]’s art skills.
The technical side of things is fairly routine in these parts – a Pi Zero runs RetroPie so you can play emulated games from the mid-90s and earlier. It’s the visual presentation that we particularly enjoy. The look of the early Atari is evoked through clever use of materials. The body is in black plastic, with blocky red buttons for controls. It’s finished with a vinyl woodgrain applique around the screen, and we think it’s a wonderful aesthetic.

The files to print your own are available on Thingiverse, and [Christian] has provided a basic guide to sourcing similar parts. It’s all common stuff, readily available on eBay or elsewhere.

We love seeing retro throwbacks like this – the tiny Macintosh Plus from the 2017 Superconference is a particular highlight.

HD Video and Telemetry Link Uses Standard WiFi Hardware

[GlytchTech] decided to implement his own Digital Data Link (DDL) for his drone experiments, and by using a Raspberry Pi Zero and some open-source software, he succeeded in creating a mostly self-contained system that delivers HD video and telemetry using an Android phone as a display.

USB tethered Android phone used as a display and touch interface.

The link uses standard WiFi hardware in a slightly unusual way to create a digital data link that acts more like an analog system, with a preference for delivering low latency video and a graceful drop-off when signal quality gets poor. A Raspberry Pi Zero, Alfa NEH WiFi card, external antenna, battery, and a 3D printed enclosure result in a self-contained unit. Two are needed: one for each end of the link. One unit goes on the drone and interfaces to the flight controller, and the other is for the ground station.

A companion android app allows for just about any old Android phone to serve as video feed, on-screen display of telemetry data, and touchscreen interface.

The software is DroneBridge (GitHub repository) and it implements Wifibroadcast which uses WiFi radios, but without the usual WiFi functionality. A Raspberry Pi is the usual platform, but there’s also an ESP32 port. The software is capable of even more, but so far suits [GlytchTech]’s needs just fine, and he was able to refine his original Watch_Dogs-inspired hacking drone with it.