Accelerometer Poi

September 12, 2013 by Marsh 15 Comments

accelerometerPoi

Even if you’ve never attended a rave, you have probably seen one portrayed on film or television. Those glowing spheres-on-a-string being swung around are called poi, and [Matt Keeter] has designed a pair with an accelerometer upgrade. Poi have a long history and were originally made from plants, but contemporary examples usually feature some kind of light, whether it’s fire, LEDs, or even glowsticks tied to shoelaces.

This build required double-sided PCBs and [Matt] had to custom make the protective covering that slips over the board. The poi are powered by 2 AA batteries fed into a 5V boost regulator. But wait, no microcontroller and no PWM? Actually, we think it’s quite clever that [Matt] took the output from the accelerometer and fed into an inverting amplifier. This keeps the voltage constant while allowing the accelerometer to vary the current. Had he used PWM, the fast motion of the swinging poi would instead produce a blinking effect.

An additional trimmer potentiometer accounts for variability in the accelerometers’ output by adjusting the default brightness. If the recent recap of Burning Man has you excitedly planning to attend next summer, you’d probably find plenty of opportunities to use these in the desert.

An Improved Bubble Display With RGB LEDs

September 10, 2013 by Marsh 14 Comments

Making a bubble display is quite an undertaking, but [Jay] takes advantage of iterative design to construct this impressive (and at 60 tubes, massive) bubble display. The display functions by dispensing bubbles to serve as illuminated pixels in each tube as they rise through the fluid. His build log steps through the display’s construction with a keen attention to detail and above all, patience.

Rather than diving right in and slapping some tubes together, [Jay] took the time to research other bubble display projects, including one we featured a few years back that grew out of yet another HackaDay article. His prototypes started off small to test potential features: whether to use water or glycerin, timing for the air pumps and bubble size, and several others. [Jay] even filled the log with videos of every test, so you can watch the problems and solutions unfold at each step.

The finished display boasts sixty 30″ tall tubes, making it 64″ wide. [Jay] also installed RGB LEDs at every edge where the tubes meet to better distribute the light. You can watch one of the many videos of the display at work below.

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Graffiti Briefcase For Stealth Tagging

September 9, 2013 by Marsh 251 Comments

We’re floored by painter and engineer [Bob Partington’s] graffiti briefcase, which proves how well art and tech can complement one another. Fear not, Arduino haters, [Bob]’s case is an analog dream: no microcontrollers here.

The guts consist of 2 components: a linear drive system and a trigger assembly. The former takes advantage of a small RC motor with a chain drive which slides the can’s mounting unit along two stainless steel rods. The latter includes a custom wound solenoid plugged into a 24V cordless drill battery, which slams down 5 pounds of force onto the can’s nozzle to fire the paint.

This all fits into an otherwise inconspicuous looking briefcase to provide some urban camouflage. The final component is a stencil, which slides into a rectangular hole on the bottom of the case. The paint can sprays downward through the stencil and tags the ground at the touch of a brass button located near the handle. [Bob] has plenty of other cool inventions you should check out that are less illegal. Or, stick it to the man by automating your tagging with Time Writer.

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‘conus’ Mixes Media, Math And Mollusks

September 5, 2013 by Marsh 14 Comments

conusCA

We love art installations that use technology in ways probably never before considered, and Moscow media artist [Dimitry Morozov] has done just that with ‘conus’, which reads the surface of mollusk shells and translates the data into real-time audio and video. These shells are unique; their pigmentation generates natural cellular automata. (If you’ve never heard of cellular automata, Conway’s Game of Life is a good example, where a rule set determines whether a cell lives, dies, or regenerates.

[Dimitry’s] installation uses homemade digital microscopes to scan the naturally-created cellular automata of several shells, each rotating on its own disc. As the shell spins, the scans from the microscopes are fed into an algorithm which transforms the signals into data for multiple audio channels and three video monitors. You can watch the mathematical translation of the biologically-formed patterns in a video after the break.

Check out the MSP430 game of life shield for another example of cellular automata.

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A Think-tank Solution For Monitoring Radioactive Water Storge Tanks

August 31, 2013 by Mike Szczys 46 Comments

SONY DSC

When we hear reports of radioactive water leaking into the ocean from the [Fukushima Dai-Ichi] plant in Japan we literally have to keep ourselves from grinding our teeth. Surly the world contains enough brain power to overcome these hazards. Instead of letting it gnaw at him, [Akiba] is directing his skills at one solution that could help with the issue. There are a number of storage tanks on site which hold radioactive water and are prone to leaking. After hearing that they are checked manually each day, with no automated level monitoring, he got to work. Above is the wireless non-contact tank level sensor rig he built to test out his idea.

A couple of things made this a quick project for him. First off, he just happened to have a MaxSonar MB7389 waterproof sonar sensor on hand. Think of this as a really fancy PING sensor that is water tight and can measure distance up to five meters. [Akiba’s] assumption is that the tanks have a hatch at the top into which this sensor would be positioned. The box next to it contains a Freakduino of his own design which includes hardware for wireless communications at 900 MHz. This is the same hardware he used for that wireless toilet monitor.

We really like seeing hacker solutions to environmental problems. A prime example is some of the cleanup hacks we saw around the time of the BP Gulf of Mexico oil spill.

Making Keys After The Apocalypse

August 25, 2013 by Brian Benchoff 50 Comments

Making keys is an amazing art with a lot of skill and technique involved. For those of you living in a post-apocalyptic world, [Dan] has a much simpler solution to the problems of having one too few keys for your locks and deadbolts – just cast them out of scrap with the power of the sun.

To make the mold of the key, [Dan] is using a two-piece plaster of paris mold. First, a thick layer of plaster is laid down in a small container and the key floated on the surface. After drying, sprues are put in with clay and the key embedded in a curing plaster block. After a few hours, a proper mold is created ready to receive molten metal.

The casting material is zinc – not as hard as the original steel key, but more than strong enough to turn a lock. This zinc is melted in a steel and plaster crucible with a gigantic fresnel lens.

As for the utility of this method of copying keys after the apocalypse, we’ll have to wonder how practical this method is. A giant fresnel lens isn’t just something you randomly find unless you’re going house to house looking for projection TVs, and finding a can of mold release after the end of the world is beyond credulity. That said, it’s a cool demonstration of metal casting that can be easily accomplished at home or at any hackerspace.

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Ultrasonic Anemometer For An Absurdly Accurate Weather Station

August 21, 2013 by Brian Benchoff 41 Comments

With his meteorological interests, [Carl] builds weather stations. Temperature and humidity sensors are a dime a dozen, but with his DIY ingenuity, [Carl] has built some very interesting and complicated devices. The latest of which is an ultrasonic wind sensor that uses the time of flight of ultrasonic pulses to detect how fast the wind is blowing.

[Carl]’s sensor uses four ultrasonic transducers aligned to North, South, East, and West to detect the wind speed. By measuring the time it takes an ultrasonic pulse to travel between the sensors indoors, Subtracting the in-situ measurement gives him the time of flight for each axis, and thus the wind speed.

It’s an impressive display of engineering that comes with an amazingly detailed design report. After three months of operation, [Carl] has found his ultrasonic anemometer is better than the traditional mechanical ‘egg-cup’ anemometer at measuring low wind speeds. The only real problem with the build is the fact the design makes a great bird perch, but some fine steel wire quickly corrected that problem.