Misc Hacks

4174 Articles

Digital Light Processing, So Many Tiny Mirrors

March 22, 2015 by 29 Comments

Did you know there are a million little mirrors flickering back and forth, reflecting light within some modern projectors; like a flip-dot display but at the micro level? In his video, [Ben Krasnow] explains the tiny magic at work in DLP, or digital light processing technology with a scaled up model he constructed of the moving parts.

LCD projectors work much like old slide projectors. Light is shined through a transparent screen containing the image, which is then focused and enlarged through a lens. DLP projectors however achieve the moving image in a slightly different way. A beam of focused light is shined onto a chip equipped with an array of astonishingly small mirrors. When the mirror is flipped in one direction, it reflects the light out through the lens and creates a visible pixel. When the mirror is tilted the opposite direction, no light is reflected and the pixel is dark. All of these tiny moving parts are actuated by means of static electricity, and since a pixel can effectively only either be in an on or off state without any range of value in-between, the pixel must flutter at a rate fast enough to achieve the illusion of intensity, much like pulsing an LED to create a dimming effect.

In addition to slicing open the protective casing of one of these tiny micro-mirrored chips to give us a look at their physical surface under a microscope, [Ben] also built his own functioning matrix from tiles of mirrors and metal washers sandwiched around pieces of string. A wound electromagnet positioned behind each tile tilts the pixel into position when a current is run through the wire — although he didn’t sink the time needed to build out the full array in this manner (and we don’t blame him). If you do have the time and add in a high powered flash-light, this makes for an awesome way to shine messages on your roommate’s wall.

Continue reading “Digital Light Processing, So Many Tiny Mirrors” →

Toggle Magnet

Switchable Magnet With A Simple Circuit

March 17, 2015 by 26 Comments

Magnets are awesome. Electromagnets are even cooler. But what if you could make a semi-permanent switchable magnet that acts like an electromagnet, but doesn’t use any energy to hold metal? You’re going to want to take a look at this Low-power Magnetic Hold and Release Mechanism.

It’s actually a very simple concept. It is basically an electromagnet attached to a permanent magnet — it’ll hold any metal object exactly as you’d expect — but if you run current through the inductor attached to it, the magnetic field created by the electricity will temporarily cancel out the field of the magnet — thus freeing your object being held. Since gravity is pretty fast acting, this impulse of current doesn’t need to be very long, only fractions of a second.

Now the real question is how big could you go? We covered another project a while ago called Open Grab which discusses the possibility of using technology like this in Quadcopters.

For a solution that uses no power at all take a look at switchable magnet clamps used for welding — they’re pretty cool — but patent protected of course.

Happy Pi Day. 3.14159265359……

March 14, 2015 by 72 Comments

Unless you were alive in 1592, this is the closest to the perfect “Pi day” you’ll ever get.  3/14/15.  And if you want to take a moment to pause at 9:26:53 (am or pm?  Time zone? Country?) we’ll be right there with you. Well, sorta of.

Now, before you laugh, and think Pi is just a number, think again.  It’s almost magical in nature.  It’s effects on our daily lives is found everywhere.  From biology to astrophysics.  In the perspective of history, it can be used as a milestone to mark many different culture’s advancement of math and science.  In short, Pi is a keystone of the modern world.  With out it, we’d never would have gone to the moon. We might sill be on horse back.  And forget electronics.  That fun stuff never would have happened.

(As a side note, on this day, 3/14,  just happens to be Albert Einstein birthday.  Happy birthday!)

We hope you have an awesome Pi day.  We would love to see you in the comments too.  For example, we’d love to hear about and see posts of algorithms that can compute Pi.  How far can you compute Pi on a Raspberry Pi?  Or even child hood stories of your first encounter with that magical number.  Post up, and let us know your thoughts.

We’ll leave you with this cute video after the break, It’s an 8-year-old reciting 200 digits of Pi .  But if you need more digits….There is 1 million digits of pi.

Continue reading “Happy Pi Day. 3.14159265359……” →

Nerdalert: German TV Producers’ Amazing Vectorscope Animations

March 14, 2015 by 21 Comments

German weekend late-night comedy show “Neo Magazin Royale” has a bunch of super-nerds behind the screens in the production studio. This is apparently what they do when they’re (not) working: making test screens that render as multiple animations on their test equipment.

While others out there are limited to displaying cool graphics on oscilloscopes, these guys have vectorscopes and waveformer monitors. A vectorscope is like an oscilloscope in X-Y mode, but with one screen that decodes the color space and one screen for the audio (in stereo). A waveform monitor that plots out the brightness levels of a test image. Normal studio techs use these to calibrate their colors, brightness, and audio levels.

Apparently, these guys programmed a custom test screen that would: a) encode a small animation of a 20-sided die spinning around the show’s logo in the color channel b) encode the show’s logo in the left and right sound channels, and c) their production company’s logo in the screen’s brightness.

At the end of the video, the director Patrick (in the glasses) admits that they’ve spent about three months working on this project and everyone starts laughing. “And who gets anything from this? Nobody!” says the show’s host.

One way to rectify that, though. Post the source code!

Bike Stand

Dirt Cheap Plywood Bike Holder

March 9, 2015 by 24 Comments

Commuting to work on a bicycle saves tons of dough, but sometimes storing your bike isn’t that easy. [Lewis] has been playing around with a few prototype bike stands and seems to have found the ticket, and it’s way cheaper –maybe even free, if you have the supplies. All you need is a single strip of plywood, and some wood screws, or wood glue! Well, that and a woodworking clamp.

The stand is designed to clamp onto 4×4 posts, or even a 2×4 stud. It’s great for storing bikes along your fence! It’s built purposefully snug, which allows you to add a small clamping force to make for a very rigid stand, suitable for even old steel-framed clunkers. Hooray for friction! Oh and if you’re happy with the location you could always get rid of the clamp and screw it in place instead.

Simple? Yup. Effective? Totally.

Oh and if it’s still crummy old winter where you live, why not beat the cold weather blues with an indoor bicycle roller?

Artist Inadvertently Builds Hodoscope

March 6, 2015 by 31 Comments

A Hodoscope is an instrument used to determine the trajectory of charged particles. It’s built out of a three-dimensional matrix of particle detectors – either PIN diodes or Geiger tubes – arranged in such a way that particles can be traced along coincident detectors, revealing their trajectory.

This is not a hodoscope. It’s a chandelier. This chandelier is made of 92 individual Geiger tubes, each connected to a single LED fixture and a speaker. When a charged particle flies through the room and hits a Geiger tube, the light fixture lights up, a ‘click’ plays on the speaker, and the entire room is enveloped in light for a short moment in time. If, however, that charged particle continues on to another Geiger tube, the trajectory of the particle can be deduced.

The purpose of the installation – beside just being art or something – is to show the viewer sources of radiation and normal levels of radioactivity due to terrestrial and cosmic sources. Of course the spacing of these detectors is rather large – it’s made to fit in a gallery – and there is no connection between the detectors, making a coincident circuit impossible. If you want a real hodoscope, here you go.

This installation can be seen at the Burchfield Penney Art Center in Buffalo, NY through April 12. If you’re in the area, go there and eat a banana. Video below. Thanks [David] for the tip.

Continue reading “Artist Inadvertently Builds Hodoscope” →

Big Jacobs Ladder

11,000 Volt Jacob’s Ladder Sounds Like A Lightsaber

March 5, 2015 by 35 Comments

In the high-voltage world, a Jacob’s ladder is truly a sight to behold. They are often associated with mad scientist labs, due to both the awesome visual display and the sound that they make. A Jacob’s ladder is typically very simple. You need a high voltage electricity source and two bare wires. The wires are placed next to each other, almost in parallel. They form a slight “V” shape and are placed vertically. The system acts essentially as a short-circuit. The voltage is high enough to break through the air at the point where the wires are nearest to each other. The air rises as it heats up, moving the current path along with it. The result is the arc slowly raising upwards, extending in length. The sound also lowers in frequency as the arc gets longer, and once [Gristc] tuned his system just right the sound reminds us of the Holy Trilogy.

We’ve seen these made in the past with other types of transformers that typically put out around 15,000 Volts at 30mA. In this case, [Gristc] supersized the design using a much beefier transformer that puts out 11,000 Volts at 300mA. He runs the output from the transformer through eight microwave oven capacitors as a ballast. He says that without this, the system will immediately trip the circuit breakers in his house.

In the demo video below, you can see just how large the arc is. It appears to get about 10 inches long before breaking with a sound different from any Jacob’s ladders we’ve seen in the past as well. Continue reading “11,000 Volt Jacob’s Ladder Sounds Like A Lightsaber” →