Raspberry Pi Chiptune Player Rocks A Sound Chip From The 80’s

September 4, 2016 by Donald Papp 13 Comments

Sometimes it’s worth doing something in an inefficient way. For example, it might be worth it in order to learn something new, or just to use a particular part. [Deater] did just that with the Raspberry Pi AY-3-8910 Chiptune Player (with LED visualizers!)

The venerable General Instrument AY-3-8910 series sound chips were common in older hardware like home computers and game consoles as well as sound cards for the Apple II family. They were capable of generating three channels of square waves with various effects. Developers eventually squeezed every little bit of performance out with clever hacks. The Raspberry Pi has more than enough power to do all this in software, but as [Deater] puts it, it’s far more interesting to use an actual AY-3-8910 from the 80’s. Some LED bar graphs and matrices round out the whole system.

All the code for the Raspberry Pi AY-3-8910 chiptune player can be found on [deater]’s github repository for the project. A video of the player banging out some sounds is embedded after the break.

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“Starry Night” Dress Shines On The Experience Of Multiple Builds

September 2, 2016 by Donald Papp 10 Comments

[Dave Hrynkiw] wrote up some practical and useful detail around embedding electronics into clothing. It centers around his daughter’s “Starry Night” high school graduation dress, which is the culmination of a lot of experimentation in finding the best way to do things. His daughter accented the dress with LEDs to produce a twinkling starfield effect, and a laser-cut RGB pendant to match.

While [Dave] is the president of Solarbotics and pitches some products in the process of writing it all up, the post is full of genuinely useful tips that were all learned though practical use and experimentation. Imagine how awesome it must be growing up a child of a “local technology-hacking company” founder — akin to growing up as Willy Wonka’s progeny.

What advice does [Dave] have for making electronics an awesome part of garments? For example, the fact that regular hookup wire isn’t very well suited to embedding into clothing due to the need for high flexibility. There is also the concept of sequestering electronics into a separate Technology Layer — a must for anything that will be used more than once. The idea is to “build your technology so it can be isolated from the fashion aspect as much as possible. It makes building and maintenance of both the fashion and technology aspects much simpler.”

Slapping some LEDs and a battery pack into clothing might do the trick if all you care about is some bling, but if you want something that actually highlights and complements clothing while also being able to stand up to repeated use, this is a great read. A simple lighting effect that complements a design isn’t difficult, and there’s no need to reinvent the wheel or make the same mistakes others have encountered. Video is embedded below.

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Dirt Cheap VR Gun With Tracking For $15 Of Added Hardware

August 28, 2016 by Donald Papp 2 Comments

Virtual reality doesn’t feel very real if your head is the only thing receiving the virtual treatment. For truly immersive experiences you must be able to use your body, and even interact with virtual props, in an intuitive way. For instance, in a first-person shooter you want to be able to hold the gun and use it just as you would in real reality. That’s exactly what [matthewhallberg] managed to do for just a few bucks.

This project is an attempt to develop a VR shooting demo and the associated hardware on a budget, complete with tracking so that the gun can be aimed independent of the user’s view. [matthewhallberg] calls it The Oculus Cardboard Project, named for the combined approach of using a Google Cardboard headset for the VR part, and camera-based object tracking for the gun portion. The game was made in Unity 3D with the Vuforia augmented reality plugin. Not counting a smartphone and Google Cardboard headset, the added parts clocked in at only about $15.

Using corrugated cardboard and a printout, [matthewhallberg] created a handheld paddle-like device with buttons that acts as both controller and large fiducial marker for the smartphone camera. Inside the handle is a battery and an ESP8266 microcontroller. The buttons on the paddle allow for “walk forward” as well as “shoot” triggers. The paddle represents the gun, and when you move it around, the smartphone’s camera tracks the orientation so it’s possible to move and point the gun independent of your point of view. You can see it in action in the video below.

Tracking a handheld paddle with a fiducial marker isn’t a brand new idea; We were able to find this project for example which also very cleverly simulates a trigger input by making a trigger physically alter the paddle shape when you squeeze it. The fiducial is altered by the squeeze, and the camera sees the change and registers it as an input. However, [matthewhallberg]’s approach of using hardware buttons does allow for a wider variety of reliable inputs (move and shoot instead of just move, for example). If you’re interesting in trying it out, the project page has all the required details and source code.

This isn’t [matthewhallberg]’s first attempt and getting the most out of an economical Google Cardboard setup. He used some of the ideas and parts from his earlier DIY Virtual Reality Snowboard project.

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Abusing A Cellphone Screen With Solenoids Posts High Score

August 25, 2016 by Donald Papp 10 Comments

This Raspberry Pi 2 with computer vision and two solenoid “fingers” was getting absurdly high scores on a mobile game as of late 2015, but only recently has [Kristian] finished fleshing the project out with detailed documentation.

Developed for a course in image analysis and computer vision, this project wasn’t really about cheating at a mobile game. It wasn’t even about a robotic interface to a smartphone screen; it was a platform for developing and demonstrating the image analysis theory he was learning, and the computer vision portion is no hack job. OpenCV was used as a foundation for accessing the camera, but none of the built-in filters are used. All of the image analysis is implemented from scratch.

The game is a simple. Humans and zombies move downward in two columns. Zombies (green) should get a screen tap but not humans. The Raspberry Pi camera takes pictures of the smartphone’s screen, to which a HSV filter is applied to filter out everything except green objects (zombies). That alone would be enough to get you some basic results, but not nearly good enough to be truly reliable and repeatable. Therefore, after picking out the green objects comes a whole chain of additional filtering. The details of that are covered on [Kristian]’s blog post, but the final report for the project (PDF) is where the real detail is.

If you’re interested mainly in seeing a machine pound out flawless victories, the video below shows everything running smoothly. The pounding sounds make it seem like the screen is taking a lot of abuse, but [Kristian] mentions that’s actually noise from the solenoids and not a product of them battling the touchscreen. This setup can be easily adapted to test out apps on different models of phones — something that has historically cost quite a bit of dough.

If you’re interested in the nitty-gritty details of the reasons and methods used for the computer vision portions, be sure to go through [Kristian]’s github repository where everything about the project lives (including the aforementioned final report.)

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Modified R/C Jet Cannon Spews Nerf, Slays Cardboard Tanks

August 22, 2016 by Donald Papp 14 Comments

[ajw61185] made a video overview of a radio-controlled A-10 jet modified to spew a hail of harmless Nerf balls as it strafes helpless cardboard cutouts of T-72 tanks on a bright, sunny day.

The firing assembly in the jet comes from a Nerf Rival Zeus Blaster, which is itself an interesting device. It uses two electric flywheels to launch soft foam balls – much like a pitching machine. With one flywheel running a little faster than the other, the trajectory can be modified. For example, a slight topspin gives the balls a longer and more stable flight path. Of course, foam balls slow down quickly once launched and at high speeds the aircraft can overtake the same projectiles it just fired, but it’s fun all the same.

Cramming the firing assembly into aircraft took some cleverness. The front of the jet contains the flywheel assembly, and a stripped-down removable magazine containing the foam balls fits behind it. A flick of a switch on the controller spins up the flywheels, and another flick controls a servo that allows the balls to enter the firing assembly and get launched. The ammo capacity on the jet is low at only twelve shots per load, and it fires all twelve in roughly half a second. Since the balls are fired at the ground in a known area, they’re easy to retrieve.

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DIY Command Station For Kerbal Space Program Is Overkill

July 25, 2016 by Donald Papp 16 Comments

We’ve seen custom controller mods for Kerbal Space Program before, but a group calling themselves the Makerforce went a step further with their design and build of the KSP “Overkill” Command Station, which has much more in common with a fancy standup arcade unit than a custom controller. Kerbal Space Program is a hit indie game that, among other things, simulates the challenges of spaceflight. Like most games, you use the mouse and keyboard for control but many fans find this too limiting. With the help of a software mod that exposes control and status information over hardware serial communications, the door to full telemetry and remote control was opened to just about anyone to craft their own custom hardware such as flight sticks and status displays. Not content with the idea of having just a joystick and a few buttons critical for the flight process, this project took a different approach.

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The Most Expensive VR Experiment You’ll See All Week

July 24, 2016 by Donald Papp 9 Comments

There isn’t a lot of detail to be found behind this short demo of robot-based physical feedback for VR, but the video (embedded below) demonstrates things well. It’s an experiment in generating force feedback for virtual objects using a Baxter robot and the HTC Vive. When the user presses against a wooden block in VR, the robot presses back which simulates the mass of the virtual object. Force feedback is one of these areas in which research is ongoing, and in a variety of different directions.

Like so many other things in life, nothing beats the real thing for actual physical feedback. Also, there’s something great about giving a $25,000 robot the job of impersonating a few simple wooden blocks in VR, just so you can strap on a VR rig and basically give a robot a realistic-feeling fist bump.

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