Computer Tracking Of Billiard Balls

October 31, 2012 by Brian Benchoff 15 Comments

The folks at the London-based startup GoCardless have a pool table at their office. Being the techies they are, they decided to build a system that automatically scores games. The results, while not fully complete, are still pretty impressive for something whipped up during a 48 hour hackathon.

The automated score keeper uses a webcam duct taped to the ceiling right above the center of the pool table, The balls – red and yellow balls replace the rainbow of solids and stripes to make things easier – are found using OpenCV.

This build isn’t quite finished yet. The people at GoCardless are looking to improve the accuracy of their setup by using a camera with a higher frame rate and possibly moving on to physics simulation to predict where the balls should be. If these guys get the time, they could add something like augmented reality pool table to improve shot accuracy.

Vidia after the break.

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Launching A Balloon And Not Landing In The Ocean

October 24, 2012 by Brian Benchoff 32 Comments

In just a few short hours, the Yale Undergraduate Aerospace Association will launch their 4th high altitude balloon project into the rarefied air of the stratosphere and with any luck bring back pictures of the view high above Connecticut Long Island, Rhode Island, and Martha’s Vineyard.

Inside their surprisingly strong unibody chassis is two GoPro cameras and a triple-redundant telemetry system consisting of a custom radio system capable of transmitting over 40 miles, a cell-phone based comms system and a SPOT satellite tracker.

There is one very large problem the Yale Aerospace team has had to cope with; Because they’re launching their Skyview balloon from the eastern seaboard of the US, it’s very likely their payload could end up taking a drink in the Atlantic. To solve this problem, the team developed a novel cut-down solution: a piece of nichrome heater wire is wrapped around the line tying the payload to the balloon. If the hardware receives a signal from the ground, or has a software problem, or runs out of battery power, the nichrome circuit will release the balloon from its launch vehicle to hopefully return it to solid ground.

The Yale Aerospace team has also written a custom iOS app allowing the chase cars to track the balloon in real time – a great feature if you’re trying to communicate with several cars going down the highway. You can check out the live data from the balloon on the Yale Aerospace tracking site or just head over to their twitter to read the latest news about the flight.

Scratch-built Motor Uses A Clever Design

October 23, 2012 by Mike Szczys 17 Comments

[Lou] is on a hot streak when it comes to interesting builds. This time around he made his own motor using wood, PVC, some fasteners, and a bunch of enameled wire.

His method of building a commutator is intriguing. He first builds a rotor by cutting two opposing sides off of a PVC four-way connector and pushing a short galvanized pipe through what’s left. After adding two PVC nubs with caps and nails as pivot points he wraps the PVC and metal pipe with a continuous length of enameled wire. The enamel is then sanded off the windings around the PVC, and half is covered with electrical tape. The spinning rotor will cause the brushes to contact the bare wire during half of the rotation, and be insulated by the tape during the other half. The video after the break shows the motor in action, then walks you through each step of the build.

If you liked this video you should check out [Lou’s] water bottle rocket launcher, or his automated Ping Pong table topper which stores the game in the ceiling.

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Exploring The Mandelbrot Set In Real Time

October 23, 2012 by Brian Benchoff 33 Comments

The Mandelbrot set – the fractal ‘snowman turned on its side’ seen above – has graced the covers of magazines, journals, and has even been exhibited in art galleries. An impressive feat for what is nothing more than a mathematical function, and has become something of an obsession for [Chiaki Nakajima].

Even on modern computers, generating an image of a portion of the Mandelbrot set takes a good bit of time. When [Chiaki] discovered this fractal in the mid-1980s, the computers of the day took hours to generate a single, low-resolution image. Real-time zooming and scrolling was impossible but [Chiaki] made the best of what he had on hand and built Pyxis, a Mandelbrot set generator made entirely out of TTL logic chips (Google Translate here).

The original Pyxis connected to a desktop computer via a breakout box. while a special program toggled the bits and registers inside the Pyxis to generate pictures of the Mandelbrot set a thousand times faster than the CPUs of the day could muster.

Time marches on, and the original logic chip Pyxis is can be easily surpassed by even the slowest netbooks. There is, however, another way to build a hardware Mandelbrot set generator: FPGAs.

A few years ago, [Chiaki] began work on the Pyxis2010 (translation), an FPGA-based Mandelbrot set generator able to dynamically zoom and pan around the world’s most popular fractal. Built around an Altera Cyclone III FPGA he picked up from Digikey for $600 (no, not a dev board, just a bare chip), [Chiaki] began deadbugging his circuit directly onto the pins of the hugely expensive FPGA. A man with a steady hand and no fear if there ever was one.

Instead of connecting his Mandelbrot generator to a computer and using it as a co-processor, [Chiaki] decided he wanted something more portable. He found an old Sony PSP, removed the LCD screen, and integrated it into his circuit. After a careful bit of dremeling and fabrication, [Chiaki] had a hand-held Mandelbrot generator that is able to display images of the world’s most famous fractal faster than any desktop computer.

It goes without saying this build is incredible. The technical skill to build an insanely fast Mandelbrot generator on an FPGA is astonishing, but basing it off a logic-chip based build reaches into the realm of godliness. You can check out a video of this amazing build after the break.

Props to [Ian Finder] for sending this one in.

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Most Useless Machine: Building Elevator Edition

October 18, 2012 by Mike Szczys 41 Comments

[Niklas Roy] calls it his Perpetual Energy Wasting Machine, but we know it for what it truly is: a building-sized most useless machine. You’ll remember that a most useless machine is a bobble that uses clever design to turn itself off once you have turned it on. This does the same thing with the elevator of the WRO Art Center in Wroclaw, Poland. The one difference is that it continually turns itself on and off.

He rigged up a pulley system that travels through the stairwell of the building. Whenever the elevator door on the top floor opens it causes the call button on the bottom floor to be pressed. The same thing happens when the elevator reaches the ground floor. But he didn’t stop there. Since the device is just wasting electricity whenever the elevator moves without passengers in it, he added a meter to track the loss. It’s the guts of a printing calculator strapped to the inside of the car. Every time the doors open it adds to the total.

You can see the installation in the video clip after the jump.

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Reverse Engineering Solari Soft Flap Displays

October 17, 2012 by Mike Szczys 25 Comments

This is a side view of the guts of a one character Solari soft flap module. This is the type of mechanical display used in some transportation hubs that have a flap for each letter. The motor turns the flaps through the alphabet until it gets to the target letter. Recently [Boz] had a client approach him who needed a custom controller for a 20-character soft flap display. (Link fixed in 2022. Thanks Wayback Machine!)

The process started out with a magnifying glass and multimeter which yielded a rather complicated hand-drawn schematic. An optical encoder is used to judge which character is currently displayed. After analyzing the output using an oscilloscope [Boz] designed a PIC based driver board which is controlling the display seen in the clip after the break.

The great thing about these displays is that they don’t use any electricity except when they change letters. This sounds like the predecessor of ePaper and makes us wonder if there are any companies developing high-contrast ePaper to replace soft-flap digits?

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Reproduce 3D Printed Models By Making Your Own Molds

October 17, 2012 by Mike Szczys 36 Comments

Need fifty copies of that 3D printed whirligig you’re so proud of? It might be faster to just cast copies by using the 3D printed model to make a mold. [Micah] found himself in this situation and managed to cast one copy every 10-12 minutes using the mold seen above.

With the object in hand, you need to find a container which will fit the mold without too much waste. The bottom half of the mold is then filled with modeling clay, a few uniquely shaped objects to act as keys, and the model itself. After getting a good coating of release agent the rest of the mold is filled with a silicone rubber product which is sold for mold making. This creates one half of the mold. After it cures the clay and key objects are removed, everything is sprayed with the release agent, and the other half of the mold is poured.

Now your 3D object can be copied by pouring two-part resins in the to shiny new mold.