Here’s a talking reverse geocache puzzle box which [Erv Plecter] built as a wedding gift for his friends. The box itself isn’t really the gift, but a surprise delivery system for a collection of cash from the couple’s circle of friends to go toward the honeymoon. We think this is about fifty times more fun that getting a fat envelope of bills. Who would really expect to find cash inside once you finally get to the target location?

Unlike the other geocache box we saw recently, this one has no display to show you clues to the destination. Instead, it plays back audio clips which [Erv] recorded himself. They’re quite tongue-in-cheek which is another nice personal touch. The pin seen protruding out of the right side of the box can be removed to play a clue and check the location. It’s connected by a little chain to a 5 euro-cent piece which conceals an emergency release mechanism for the lid. The device is powered with a Lithium battery and can be recharged without opening the box via a USB port in the side.

We’ve embedded the video demonstration of the box after the break.

[Ranger Bob] crafted this great looking Reverse Geocache box. Our favorite feature is the black piece of acrylic on top. It’s laser cut (not sure if the letters are engraved or not) and gives a great finished look while hiding a couple of things at the same time.

The orange box is a metal cash box, and there’s a smooth indentation in the lid where the handle resides when not being carried. [Bob] removed the handle and mounted the GPS module in that void. But there’s also an OLED display mounted next to it. As you can see in the demo video after the break, the screen is bright enough to be seen clearly through the smoky acrylic covering that depression.

This project gave [Bob] the chance to order his first professionally made circuit board. He did the design in Eagle, managing to keep within the 5cmx5cm limits of Seeed Studio’s least expensive Fusion PCB option. The board hosts the PIC 18F87J50 responsible for handing the screen, GPS module, input button, and USB port. Power comes from an internal Lithium battery.

We’ve featured a lot of Reverse Geocache boxes and they’re still one of our favorite projects because so much love goes into the design and build process. Here’s another one that we chose randomly for your amusement.

[Buxtronix] wanted to know where his cat (named Ash, but we thought Socks sounded much more cliché) was going when on the loose. He designed a GPS tracking collar and a way to map the data it collects.

The hardware actually turns out to be very simple. He needed a GPS module to gather location data, and a way to store that information having decided that live broadcast was not feasible. He hit SparkFun because they have a GPS module that is small enough for a cat collar, and outputs data with one serial pin. Unfortunately this module is no longer available, but if you have a similarly sized replacement let us know in the comments. Data capture is made easy by this device, you just need to record the serial data as it comes down the pipeline. [Buxtronix] used an OpenLog board as it dumps the data onto an SD card. When [Ash] returns from his roaming, [Buxtronix] grabs the SD card, and uses a Python script to convert the NMEA data to KML format which can be overlaid on Google Earth and Google Maps.

GPS receivers may be available for well under $100 these days, but what’s the fun in buying one when you can build it yourself? According to [Andrew], the creator of this device, he was inspired by Matjaž Vidmar who developed a GPS receiver from scratch over 20 years ago. His article can be found here and includes some nicely hand-drawn diagrams as well as a lot of theory.

However, [Andrew's] article is a bit more up-to-date and features plenty of theory itself. He explains how he built his four-channel GPS receiver, able to track four satellites at the same time. This is the minimum number of satellites needed to track your position using such a device.

GPS technology is quite incredible, and the amount of soldering as well as the understanding of the theory behind it required to build such a device is astonishing. Interestingly (sadly?), it seems we are beyond the time of LORAN hacks, but if you have an old one to share, be sure to send it in! For something a bit easier, maybe one could try making a GPS “cateye” to track what your pet does all day!

[Davy] and his friend [Chris] were tasked with putting together a bachelor party for their friend [J], and had a little more in mind than the standard drunken revelry. To earn the privilege of partying his brains out, they decided that [J] would have to fulfill a series of tasks and challenges before joining up with the rest of his friends for the evening’s events. [Davy] didn’t specify what these tasks were, lest he spoil the surprise, but he did let us in on a little device that he and [Chris] built to help guide the bachelor through his day.

They were a bit worried that the bachelor would get sidetracked during his journey if he happened to imbibe along the way, so they built a device called jGPX that would ensure [J] stayed on track and on time. jGPX is a custom GPS navigator consisting of an Arduino, a GPS module with built-in antenna, and a compass.  The pair created a set of routes in Google Earth, exporting the data to KML for interpretation by their device. The jGPX is meant to guide [J] along via a small LCD screen that shows him the distance to his target as well as the proper direction of travel to get there.

It looks like [J’s] friends put a lot of effort into his party, and although there are no details as to how things went, we’re sure it was a blast!

The team at Eschelle Inconnue wanted to “trace a sound cartography of Islam” in Marseilles, France, so they came up with a clever little GPS walking tour powered by an Arduino, MP3 playback module, and a surface transducer speaker.

The team used a Processing app to define geographic areas where each MP3 file would play. An Arduino on the build queries a GPS module and selects the audio file from an MP3 playback module. This isn’t uncommon, and a lot of large outdoor museums (think battlefields) have similar setups.

Determining which audio to play at what location is fairly easy, but that’s not what makes this build special. Instead of simply hooking up a pair of headphones to the build, the team decided to use a surface speaker that turns just about any solid material into a speaker. From the writeup, this is supposed to, “diffuse sounds by giving the illusion to collect them, to listen to the words of the walls, the whisperings through the materials” but we think it’s just a great way to have several people listen to the same audio file at the same time.

The team at czANZO, the Czech Amateur Near-Space Object group, sent up one of the best high-altitude balloons we’ve ever seen last weekend and the resulting video is remarkable.

The team’s build blog (Google Translate link for everyone without Chrome) goes through the design and construction of their payload. Like every other balloon build we’ve seen, a styrofoam cooler is used for the enclosure, but there’s a lot of really neat additions that make this build special.

The team included a cut down device in the event the balloon gets caught in the jet stream. Without this cut-down device the balloon could end up hundreds of miles away from the launch point. That’s the reason for the cut-down device they’ve given, although we suspect it’s an excuse to play around with pyrotechnic rope cutting. The optical and audible alarm is something we haven’t seen on many high-altitude balloon launches, which is odd because it made ground recovery much easier.

The team has a lot of video from the flight that [Pavel Richter] dumped onto Vimeo. We really like the footage showing all of Prague, you can check that out after the break.

Imagine our surprise when we learned [Bruce Simpson], who made headlines in 2003 with his $5000 DIY cruise missile, is still alive, not illegally interned in a black ops prison, and still doing what he does best: building really awesome remote-control airplanes.

The first successful mass-produced pulse jet aircraft was the German V-1 flying bomb. The V-1 had a very primitive guidance system, but the unmanned pulse jet aircraft quickly evolved into a few target drones used by the US Air Force. There was never any significant advancement towards improving the fuel consumption, noise level, or heat signature of pulse jets, so they were superseded by the superior turbojet. Despite their failings, pulse jets are remarkably easy to build and amazingly fast.

Instead of being antagonized by the New Zealand and United States governments, [Bruce] spends most of his time now working on pulse jet projects. He’s flown quite a few modified R/C planes and has an electronic Engine Control Unit for his jets. One of his most impressive projects is the 100 pound thrust pulse jet that was later attached to a go-kart. His no weld version of a pulse jet can be built in even the most minimalist work shop and is the epitome of an easy-to-build jet engine.

To get an idea of how fast [Bruce]‘s planes can be, check out his Long-EZ R/C pulse jet in action after the break.

[Janis] has an outdoor cat that likes to roam all over the neighborhood. He was curious to see what he was up to all day, so he decided to build a small cat cam to document the feline’s comings and goings. After the cat returned one evening with a snail riding along on his back, [Janis] thought it would be pretty interesting to see where the cat was going as well.

He calls his creation “CatEye”, and it consists of a small JPEG color camera and GPS sensor, both of which are managed by what looks to be an ATMega328. The camera snaps pictures as the cat roams around, while the GPS sensor records its location throughout its travels. All of the data is stored on an SD card, making it easy to transfer the pics and .KML files back to his computer. A few clicks later, he can see everywhere his cat has been, using Google Earth.

It seems like a pretty interesting project, and we would love to see some schematics and code so that we can strap one of these on [Caleb] our cat to see where he’s been all day.

Hackaday forum member [nes] was training for an endurance race, and rather than having someone verbally call out his lap times, he wanted something he could keep in-vehicle to help keep track of his performance. With the race budget running dry, he and his teammates needed something cheap, if not free, to get the job done.

He scored a “broken” GPS receiver on eBay for a measly £4 and found that the receiver worked, but corrupted software prevented the unit from mapping routes. Since he didn’t require routing functions to keep track of his lap times, he splayed the GPS receiver open and started hunting around for a serial bit stream. He found what he was looking for after a bit of probing and hooked it up to his computer to see if the data contained NMEA sentences.

He cut the receiver down to the necessary parts and then started work on the lap timer itself. The timer uses an ATMega32 to run the show, displaying relevant time and location information on an LCD panel he scavenged from the trash bin.

He admits that the wiring is a bit questionable, but says that after about seven hours of rough use, everything is still intact and working great.

While some people can rely solely on memory and landmarks to find their way home, others need a bit more help. Consider Instructables user [_macke_] for instance.

Like other screenless GPS navigation devices we have seen, his “Find Home Detector” uses a GPS module to obtain his location, guiding the way home via a set of alternate indicators. In this case, he uses LEDs which are laid out like a compass rose. When [_macke_] is aimed toward his destination, the LED nearest to his fingertips lights up, letting him know he is on the right path. As he turns away from home, the other LEDs light, indicating the direction in which he should turn.

His forearm-mounted GPS navigator uses a LilyPad Arduino to control the system, much like others we have seen. It is connected to a GPS sensor and a compass module that work in concert to guide him home. The compass is responsible obtaining his heading information, and while it might look as if the LEDs that surround the module are pointing North, they are in fact indicating the heading of his destination instead.

It’s a cool little creation, and we can imagine it would be quite helpful if you happen to be walking home after a long night of drinking.

Be sure to check out the video below for a quick demonstration.

We’re not sure if this is the first time, but here’s some pretty solid proof that Arduino has found its way into the weapons of war. The creators, [Derek Wales], [John Eischer], and [George Hopkins] are all Electronics Engineering majors at West Point. They came up with this idea after seeing video footage of a firefight in Afghanistan where combat soldiers were calling in artillery strikes using a compasses and GPS devices. It’s an all-in-one unit that can provide the same information quickly and accurately. The prototype above, which they call the DemonEye, contains a laser range finder, digital compass, and a GPS module. The article also states that it contains a mini-computer but we recognize that as an Arduino Mega (thanks to Miguel over at Areopago 21 for noticing this first and sending in the tip about it).

The prototype apparently comes in at $1000. Okay, it seems a bit high but not out of the ballpark. What we can’t understand is how the second generation of devices was billed out at $100,000 for five more units. What’s the going rate for laying out military-grade PCBs?

The hackers over at the xda-developers forum always seem to have something awesome brewing, and [fosser2] is no exception. He bought himself a Viewsonic G-tablet, but was a bit disappointed in its lack of a GPS module. He pried the tablet open in hopes of finding a spot where he might be able to cram one in, and was happily surprised at what he found.

It turns out that either Viewsonic had plans to include a GPS module and scrapped them, or they are planning on adding GPS to a future SKU. The tablet’s mainboard already had a spot laid out for the module, as well as the GPS antenna. He carefully soldered in a compatible module from Digikey, and then got to work adding the various other components required to get it working properly.

While the hack doesn’t require that you add a ridiculous amount of parts to the board, you had better make sure your soldering skills are up to snuff before giving it a shot. Those who can’t reliably solder SMD components should probably stay away from this one.

[via Engadget]

[ifixit] has apparently grown tired of tearing apart Apple’s latest gizmos, and their latest display of un-engineering has a decidedly more federal flair. You may have heard about Yasir Afifi’s discovery of a FBI-installed tracking device on his car back in October of last year. Apparently, the feds abandoned a similar device with activist Kathy Thomas. Wired magazine managed to get their hands on it, and gave it to ifixit to take apart. There’ve even posted a video.

The hardware itself isn’t that remarkable, it’s essentially a GPS receiver designed before the turn of the century paired with a short range wireless transceiver. The whole device is powered by a set of D-sized lithium-thionyl chloride batteries which should be enough juice to run the whole setup for another few decades–long enough to outlast any reasonable expectations of privacy, with freedom and justice for all.

The latest project from Lucidscience.com is a simple AVR based GPS tracker. As usual, the instructions here are quite in-depth including schematics and step by step procedures all the way down to modifying cables when necessary. What we found interesting is that the GPS module he’s using is so simple. It only requires 3 wires, one for power, one for serial communication, and one for a heartbeat.

For the microprocessor, he’s using an ATMega 324, which is a bit of processing overkill but he needed the SRAM for the GPS point storage. You could obviously expand to external storage but the goal here was to keep it extremely simple. Actually, there just isn’t a whole lot here other than the microprocessor, the GPS module, and a level converter. After wrapping up the circuit he goes on to explain how to get the data into Google Earth for display. After a few trips around the block you can see the results are quite nice.