Acoustic Barcodes Deliver Data With A Fingernail And Microphone

October 11, 2012 by 44 Comments

Either through QR codes, RFID, or near field communication, there seems to be some desire to share tiny pieces of data in a more physical and accessible form. [Chris Harrison], [Robert Xiao], and [Scott E. Hudson] of the HCI Institute at Carnegie Mellon have come up with a fairly interesting solution of making data more physical. They call it Acoustic Barcodes, and it’s able to store over a billion unique IDs in a small strip of plastic.

By engraving a barcode pattern into a piece of wood, stone, glass, or plastic, the guys then attached a microphone to the barcode and ran their fingernails across their invention. A computer interprets the sounds of a finger scraping against the acoustic barcode and produces a series of 1s and 0s.

This binary code can be used to look up various items in a database, or perform actions on a computer. In the video after the break, you can see these acoustic barcodes attached to a whiteboard to provide real tactile control of a video projector.

You can check out a PDF of the Acoustic Barcode paper here.

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Hackaday’s Portal Gun Actually Levitates A Companion Cube

October 11, 2012 by 57 Comments

I was out to lunch with a couple friends, brainstorming ideas for fun projects when one of them says “Wouldn’t it be cool if we could build a working gravity gun?”. We all immediately concurred that while it would in fact be cool, it is also a silly proposition. However, only a few seconds later, I realized we could do a display piece that emulated this concept very easily. Floating magnetic globes have been around for quite some time.

I determined I would tear the guts out of a stock floating globe and mount it on a portal gun, since they’re easier to find than a gravity gun. I would also build a custom companion cube to be the correct size and weight necessary.

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Getting Started With The Stellaris Launchpad

October 11, 2012 by 72 Comments

We’ve already given an overview of the Stellaris Launchpad, but lets look at the first steps to running code on the device. First we’ll get the development software working, then we’ll build and run a very simple example.

TI allows use of the full version of their IDE, Code Composer Studio, with the Launchpad’s on-board debugger. To work with Stellaris microcontrollers, you’ll also need to grab StellarisWare. This free software package contains support for the Stellaris devices including peripheral drivers, a USB library, and code examples. Finally, you’ll need the ICDI drivers to communicate with the debugger. TI has all the required software for this board available here. See the TI getting started directions for a walk-through of how to install the required software.

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Stare Deep Into This Well-lit Interactive Infinity Mirror

October 11, 2012 by 26 Comments

infinity-mirror

[acorv] recently sent us a link to a cool, interactive infinity mirror (Translation) he built. He was originally a bit gun-shy about sending the project our way, but our recent Reddit AMA inspired [acorv] to submit it via our tip line, and we’re glad he did.

Having been lucky enough to score $100 of gear from Sparkfun’s 2012 Free Day, he picked up a pair of addressable LED strips and a Teensy++. He built an LED ring from reflective foil, sandwiching the strips between a mirror and a piece of mirror glass. The resulting infinity mirror looked nice enough, but [acorv] wanted to make the static display a bit more interesting.

He added an IR receiver and ultrasonic rangefinder to the mirror’s frame, allowing him to both control the display remotely and detect when people were standing nearby. As you can see in the video below, [acorv] can change the patterns on a whim, and the mirror speeds up the display when someone stops to take a closer look.

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Nixie Clock Without A PCB

October 11, 2012 by 23 Comments

Looking for an artistic way to build circuits? Don’t want to design a PCB? The Lethal Nixie Tube Clock is a free form circuit that gives you the time one digit at a time. It uses a IN-1 Nixie tube to display the digits. This is driven by ten MPSA42 high voltage transistors. A IRF520 N-FET, inductor, and a diode are used as a switching power supply that generates the high voltage needed to drive the Nixie tube. It’s probably not lethal, but there are exposed high voltages in the cube. You’d definitely regret touching it.

An ATMega8 is used to control the clock. It drives the various digits of the Nixie tube, and generates a PWM output to switch the high voltage supply. Unfortunately, the schematic has been lost. If you’re interested in the switching supply, it’s likely similar to the one explained here.

Check out a video of the clock after the break.

Via Dangerous Prototypes

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Motivating Engineering Students With Microcontrollers

October 11, 2012 by 16 Comments

We see a lot of microcontroller based hacks around here, and it’s not hard to see why learning how to use microcontrollers is valuable to prospective engineeer. Unfortunately, microcontroller courses are dreaded by students since they focus on theory instead of application. In The First Lecure, [Colin] talks to a class of engineering students about how to get practical with microcontrollers.

He starts with an overview of a bomb countdown project that he used to learn the basics of microcontrollers. This started as a 555 based timer, but he ended up using a PIC18 after having issues with timing and reliability. Next, he discusses a paintball sentry gun inspired by a Hackaday post.  He finishes off some advice and gives the students some hardware: a Pickit2 programmer and a Saleae Logic Analyzer.

It’s easy to lose motivation due to the heavy focus on theory in engineering. [Colin]’s advice to start building stuff will hopefully motivate these students to take an interest in microcontrollers. We also like how he advises students to read Hackaday. Check out the full video of the lecture after the break.

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Build Your Own Water Rocket Launcher

October 10, 2012 by 16 Comments

We feel like the days when you want to play in the water are far behind us. But if you can still find a warm afternoon here or there this water rocket launcher build is a fun undertaking. We figure most of the time spent on the project will be in shopping for the parts. They’re all quite common, and once you have them on hand it can be assembled in under an hour.

The concept is simple, but that doesn’t stop people from building rather complicated water rocket rigs. This one which [Lou] devised is rather simple but it does offer connections to a hose and air compressor (the alternative being to fill the bottle with water ahead of time and use a bike pump for air pressure). PVC is used to connect the two inputs to the bottle via a pair of valves. The bottle is held in place while water and air are applied. The launch happens when a pull on that rope  releases the bottle.

Check out the build process and bottle launch after the break. We think that rocket needs a few fins.

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