Harry Potter Wand Hack Makes Magic Real

Any sufficiently advanced hack is indistinguishable from magic, a wise man once observed. That’s true with this cool build from [Jasmeet Singh] that magically opens a box when you wave a Harry Potter magic wand in the right way. Is it magic? No, it’s a neat hack that uses computer vision to track the wand and recognize when you make the magic gesture.

The trick is based on the same technique that Universal Studios use in their Harry Potter theme park, as detailed in a patent with the snappy title of “System and method for tracking a passive wand and actuating an effect based on a detected wand path“. The basic idea is that a retroreflective dot on the end of the wand reflects light from a set of infra-red LEDs around the camera. An infra-red sensitive camera detects this reflected light as a bright dot. This camera is tied into a computer vision system that tracks the path of the dot, then triggers the action if it follows a certain pattern.

The version that [Jasmeet] built uses a Raspberry Pi NoIR camera, and a Raspberry Pi 3 running OpenCV. This feeds into a machine learning graph that detects the letters of the alphabet. If the detected letter is an A (for Alomahora, the Harry Potter open spell), then the box opens. If it is a C, the box closes. This is all tied together using Python.

It’s a neat build that ties together a number of interesting techniques, and which could keep the kids amused for a while. You could also expand it further, such as adding a death ray that triggers if you trace an S for Sectumsempra. That’ll teach them not to mess with the dark arts.

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Lighting Up Your Spectrespecs

In the ever-popular world of Harry Potter, a pair of Spectrespecs are useful if you’re hunting for wrackspurts and nargles. While we’ve never spotted either of these creatures ourselves, if you’d like to go out on a hunt, [Laveréna]’s build might be for you.

To start with, you’ll need the frames for the Spectrespecs. [Laveréna] elected to source hers commercially, but you can 3D print them or even craft them by hand if you so desire. Then, a TinyLily microcontroller board is installed, with its small size allowing it to be tucked neatly out of sight in the top of the sunglasses. Two NeoPixels are then installed, with the TinyLily programmed to flash the LEDs in the requisite blue and red colors for easy identification of supernatural creatures.

Tools such as cheap microcontrollers designed for wearables and low-cost addressable LEDs are making advanced cosplay designs easier than ever. Whipping up custom blinkables no longer requires knowledge of advanced multiplexing techniques and how to properly drive high-power LEDs. Of course, LED wearables do still get properly advanced – like this skin-based 7-segment display. If you’ve got a glowable project of your own that you’re dying to share, be sure to let us know!

Play Chess Like Harry Potter

If you are a Harry Potter fan, you might remember that one of the movies showed an Isle of Lewis chess set whose pieces moved in response to a player’s voice commands. This feat has been oft replicated by hackers and [amoyag00] has a version that brings together a Raspberry Pi, Arduino, Android, and the Stockfish chess engine in case you want to play by yourself. You can see a video of the game, below.

Interestingly, the system uses Marlin — the 3D printing software — to handle motion using the Arduino. We suppose moving chess pieces over a path isn’t much different than moving a print head. It is certainly a novel use of GCode.

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Magic Wand Learns Spells Through Machine Learning And An IMU

Jennifer Wang likes to dress up for cosplay and she’s a Harry Potter fan. Her wizarding skills are technological rather than magical but to the casual observer she’s managed to blur those lines. Having a lot of experience with different sensors, she decided to fuse all of this together to make a magic wand. The wand contains an inertial measurement unit (IMU) so it can detect gestures. Instead of hardcoding everything [Jennifer] used machine learning and presented her results at the Hackaday Superconference. Didn’t make it to Supercon? No worries, you can watch her talk on building IMU-based gesture recognition below, and grab the code from GitHub.

Naturally, we enjoyed seeing the technology parts of her project, and this is a great primer on applying machine learning to sensor data. But what we thought was really insightful was the discussions about the entire design lifecycle. Asking questions to scope the design space such as how much money can you spend, who will use the device, and where you will use it are often things we subconsciously answer but don’t make explicit. Failing to answer these questions at all increases the risk your project will fail or, at least, not be as successful as it could have been.

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Mad Eye For The WiFi

In the Harry Potter universe, Professor Moody was, perhaps unfairly, given the nickname Mad Eye for the prosthetic eye he wore. His eye remains a challenge for technically-minded cosplayers aiming to recreate the look and feel of this unique piece of headgear. [cyborgworkshop] had already mastered the basic eye, but wanted to take things further.

The original build relied on a sub-micro servo to move the eyeball. This was done at random as an attempt to simulate the eye’s behaviour in the books and films. However, wanting more, [cyborgworkshop] decided to make the eye more reactive to its surrounding environment. Using the Adafruit Huzzah, a breakout board for the ESP8266, code was whipped up to detect the number of WiFi access points in the area. The more access points, the more frequent and erratic the movement of the eye. Occasional slower periods of movement are coded in before the eye resumes its wild darting once more, depending on just how saturated the local WiFi environment is.

It’s a great twist on the project, and [cyborgworkshop] has provided more details on the initial build, too. If you think you’re having déja vu, check out this build using recycled parts.

A Shocking Wizard Duel

You’ve probably heard of Arthur C. Clarke’s third law, suggesting that any sufficiently advanced technology is indistinguishable from magic. Taking this literally and in the best possible way, [Allen Pan] of [Sufficiently Advanced] is using readily available technology to simulate magical wizarding duels in the fashion of Harry Potter.

Entitled the Wizard Analogue No-Magic Dueling Simulator — or W.A.N.D.S. for short — is a slightly more interactive version of laser tag. It’s especially engaging because your body is on the line. A Raspberry Pi using Google’s speech recognition service listens for the spell names and — remember, pronunciation is key — fires off the spell from an infrared LED tipped wand. Each duelist has five spells at their disposal, but their accuracy is up to you.

Once your opponent’s receiver registers a hit, an Arduino triggers transcutaneous electrical nerve stimulation (TENS) devices which sends pulses to various regions on the body to simulate the spell’s effect. What’s a few electrical shocks between wizards, eh?

As a defense from the constant barrage, the spell Protego — aimed at one’s own sensor — grants a few seconds immunity; however all spells have a built-in cool-down to prevent their abuse and an LED on the wand indicates when they’re ready to be used.

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Manhattan Marauder’s Map

If you solemnly swear that you are up to no good, and you happen to spend most of your time in Manhattan below the mid-90s, then you will appreciate this Raspberry Pi-based Manhattan Marauder’s Map.

Not that a Harry Potter-themed map was necessarily [GawkyFuse]’s intention when creating this interesting build; it’s just that the old-time print of Manhattan — it shows Welfare Island in the East River, which was renamed Roosevelt Island in 1971 — lends a nice vintage feel to the build. Printed on plain paper, the map overlays a 64×32-LED matrix, which is driven by a matrix HAT riding atop the Pi 3.

[GawkyFuse] uses the OwnTracks app on his and his wife’s iPhone to report their locations back to CloudMQTT. The Pi subscribes to the broker and updates his location in red and her location in blue as they move about the city; a romantic touch is showing a single purple dot when they’re together. There’s no word on what’s displayed when either leaves the map area, but the 2048-pixel display offers a lot of possibilities.

We’ve seen a Weasley clock or two around these parts before, but strangely no Marauder’s Maps like this one. Although this Austrian tram-tracking map comes pretty close to [GawkyFuse]’s nice design.

[via r/raspberry_pi]