Putting The Brains Of A Reverse Geocache On The Outside

March 20, 2013 by 9 Comments

ioio

A reverse geocache – a box that only opens in a specific geographical area – is a perennial favorite here at Hackaday. We see a ton of different implementations, but most of the time, the builds are reasonably similar. Of course dedicating a GPS receiver solely to a reverse geocache isn’t an inexpensive prospect, so [Eric] came up with a better solution. He’s using a smart phone as the brains of his geocache, allowing him to keep the GPS and display outside the locked box.

The build began by finding an old box and modifying it so it can be locked with a servo. The only other bits of electronics inside the box are an IOIO board, a battery pack, and an I2C EEPROM for storing a few settings. On the phone side of things, [Eric] wrote an Android app to serve as both the programming interface, UI, and GPS hardware for his reverse geocache. It’s exactly like all the other reverse geocaches we’ve seen, only this time the controls are wireless.

[Eric] put up a video demoing his reverse geocache. You can check that out after the break.

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Hackaday Links: March 20th, 2013

March 20, 2013 by 23 Comments

Giant fresnel lens is dangerous fun

giant-fresnel-lens-is-dangerous-fun

Here’s an interesting, and rather dangerous, use for those old big screen TVs that are frequently listed for FREE on Craigslist. With the lens from the old TV built into an adjustable wooden frame, [Grant] was able to melt a stack of pennies, instantly burn wood, melt spots in concrete, and serve his family a cooked egg… Cool.

Projection mapping app helps create hologram like performance stage

projection-mapping-app-creates-live-desktop-stage

[Aimino] used an iPad, a mobile projector, and a mosquito screen to create a trippy hologram like stage. It might not seem like much at first, but it’s actually a pretty interesting effect. Watching the video makes me wonder what other applications this could have in the near future.

The world’s strongest magnet

worlds-strongest-magnet

At a cost of over $14 million dollars and weighing in at 35 tons, the 45 Tesla Hybrid is the strongest DC magnet on Earth. It’s powerful enough that the film crew couldn’t even safely get in to take footage of it.  Over half of their camera tapes were wiped clean just while being in the same facility that houses it!

Virtual Body chair uses 4 of our 5 senses

virtual-body-chair

Created in the hopes of providing a VR experience for seniors with mobility problems who can no longer travel the world, Tokyo Metropolitan University’s Ikei Laboratory presents the ‘Virtual Body’ exhibition. Included are a 3D monitor, a pair of headphones, a fan to create breezes and spread scents, a chair that moves and vibrates, and moving foot pedals.

Iron Man laser gauntlet pops balloons with ease

functional-iron-man-laser-gauntlet

If you’re an Iron Man fan with disposable income, you might want to check out this functional full metal laser gauntlet. Built from scratch using no blueprints or guides, [AnselmoFanZero] sells them for around $3K USD.

Measuring Meditation With A Heart Rate

March 20, 2013 by 15 Comments

meditation

We’ve seen our fair share of builds over the years that attempt to peer inside a user’s head and divine their state of mind. Whether the goal is to induce lucid dreaming or just reduce anxiety, we’re always impressed with how many ways you can detect moods with physiological measurements.  [Kirk] has been measuring his own physiology for months, and found the biggest change during meditation is the variability in his heart rate. Using that algorithm, he made an orb that changes colors when he’s meditating.

The hardware for the build uses a Bluetooth LE heart rate monitor connected to a smart phone communicating with an Electric Imp. After processing the heart rate data, the Imp triggers an RGB LED strip controlled with an Arduino.  The result is a plastic orb that glows whenever the user is displaying some sort of mindfulness, cross referenced with algorithm generated from mindlessly browsing the Internet.

Hackerspace Intro: Make Lehigh Valley

March 19, 2013 by 16 Comments

make-lehigh-valley

The video tour of Make Lehigh Valley in Pennsylvania involves mostly a show-and-tell about the raw materials just waiting to find their way into members’ projects. The tour starts off outside the warehouse that house the hackerspace as well as an associated business incubator called Hive 4A. It then moves inside to give us a look at what they’ve got going on.

We love the space. There are really two kinds of buildings we see used in these tours. One type are commercial retail spaces, like HeatSync Labs or Workshop 88. They’re clean, well-lit, and in the public view. This is the other kind, behind closed doors and full or floor-space. The building features a really awesome wide-plank wooden floor. It plays host to a smattering of different equipment and a multitude of boxes, jars, troughs, and jugs full of all kinds of stuff. It looks like they’re beginning to get the parts organization under control. Old milk jugs serve as a first round of sorting. There’s also a nice little small parts rack built from plastic tea bottles and small cubby holes made of cardboard. See it all in the clip after the break.

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Carry A Git Server In Your Pocket

March 19, 2013 by 17 Comments

android-git-server

We love using Git for its superior version control. We often host our more advanced projects in a public Github repository. But the bulk of our little experiments are simply local repos. This is fine if you’re always at home, but if we are away from home we find ourselves having to SSH into our server to copy over the Git files. [Andrew] found a way around this slightly awkward process. He used an old Android phone as a Git server.

This actually makes a lot of sense when you start to think about it. Most Android phone have a microSD card slot to provide a huge storage bin (the lack of this on the Nexus 4 is baffling) so you don’t need to worry about running out of space. All of these devices have WiFi, making it easy to use them as an AP when there isn’t any other WiFi around. And the web-connected nature of the device will make syncing your repo over the Internet a snap.

Most of the behind the scenes work is done using Debian packages. This provides a few issues which [Andrew] walks through one by one. We also like his pointers like using ‘noatime’ on your EXTx file systems to avoid wear on the SD card.

Fabricating Custom Displays For A Commercial Coffee Roaster

March 19, 2013 by 14 Comments

custom-display-panel-for-a-coffee-roaster

Roasting the perfect coffee bean is an art form. But even the most talented of roasters can use a little feedback on what’s going on with their equipment. [Ludzinc] recently helped out a friend of his by building this set of 7-segment displays to show what’s happening with this coffee roaster.

The yellow modules hiding underneath the display panel are responsible for setting the speed of the hot air blower and the rate at which the drum turns. They’re adjustable using some trimpots, but it sounds like the stock machine doesn’t give any type of speed feedback other than direct observation.

The solution was to patch into those speed controllers using the ADC of a PIC chip. They each output 0-10V, which [Ludzinc] measures via a voltage divider. After the speed is quantified the microcontroller outputs to one of the displays. Since there’s a different chip for each readout, the firmware can be custom tuned to suit the operator’s needs.

Keep this in mind if you’re still planning to build that coffee roaster out of a washing machine.

Stereoscopic Display Art Installation

March 19, 2013 by 9 Comments

stereoscopic-display

This rig is something of a museum or art installation, but the concept is so simple we thought it could easily inspire your next project. The two mirrors and two video sources make up a stereoscopic display.

The user sits between two displays (computer monitors shown here, but the post also shows images projected on two walls of a room). A pair of mirrors mounted at forty-five degrees form the eye pieces. It’s a V-shaped mirror assembly in which the narrow end pointing toward the bridge of the user’s nose. The mirrors reflect the images from the monitors, giving a different view for each eye.

In this case each monitor is playing back a video loop, but one is just slightly longer than the other. Each monitor has a potentiometer in front of it. The user can turn them to speed or slow the playback in an attempt to bring the video back into sync. We don’t think we’d replicate that portion of the project. But it might be fun to view some stereoscopic clips in this way. There’s even instructions on how two cameras were used to record the scenes.

You can get a closer view of the test apparatus in the clip after the jump.

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