Morph: Adaptive Spaceframe

November 10, 2013 by 17 Comments

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[William Bondin] is working on a rather interesting project, a tetrahedron morphing robot called Morphs (Mobile Reconfigurable Polyhedra). 

It is able to move by the extension of each of its telescopic edges, and as it morphs, the centre of gravity shifts, allowing it to roll over. It is far from an efficient way to move, but it is quite entertaining to watch!

The custom two-directional linear actuators were designed to ensure the weight is symmetrically distributed on each axis, and they were able get the current draw down to about 200mA during actuation, which means with a few strategically placed battery cells, it’ll be able to go wireless too. The prototype unit is controlled by a single Arduino, which sends the commands to each motor-encoder couple.

[William] is hoping to develop it into a full scale architectural prototype, and by 2015 hopes to have these interactive robotic structures rolling around public parks. The architectural end goal is to allow for buildings to respond to environmental inputs, like daylight and temperature.

Confused? Check out the video after the break.

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Make Any Shape Board In Eagle

November 10, 2013 by 21 Comments

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[Bryan] has been working on a very nice analog LED clock circuit, but when it came time to lay out the parts in Eagle, he was somewhat miffed by the inability to create designs in his Eagle boards. Eagle is a fine tool for laying out circuits, but when it comes to making strangely shaped PCBs, Eagle just isn’t the right tool.

The solution to this problem was to create the board outline in OpenSCAD. The desired shape of [Bryan]’s clock was easily designed, but importing the shape into an Eagle layer was another matter entirely.

OpenSCAD, though, can output 2D shapes to the DXF format. Getting the DXF board into Eagle required [Bryan] to write a script that outputs Eagle WIRE commands. Pasting these commands into the command line gave [Bryan] a perfectly shaped PCB.

Since DXF is supported by every drawing package on the planet, [Bryan]’s 20 line script could also be used for much more intricate designs. If you have an incredibly complex Illustrator drawing that deserves to be a PCB, it doesn’t get much easier than tossing it through a script.

The Rabbit’s Hole: Creative Reuse And Stop Motion Animation

November 9, 2013 by 3 Comments

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The folks down at The Rabbit Hole Hackerspace have been busy lately. They’ve created an amazing stop motion animation short titled “The Rabbit’s Hole”. The three-minute film documents the journey of a white rabbit through several strange lands, including the court of a “hormonally imbalanced queen”, the sewers, a PCB wasteland, and a banana jazz concert. The rest of the video is a behind the scenes view, showing the incredible amount of teamwork that went into the film’s creation.

From set building to final photography, the entire film was shot in one day.  The set was split into 8 pieces. Each piece represented a scene the rabbit would journey through in the final movie. Members of The Rabbit Hole were able to work in parallel, each designing their own section of the set. Once the photography was done, [Whisker] took over for the process of editing and sound design. Just like in Hollywood, post production took much longer than the actual shoot.

The amazing part of the video is that most of the characters and set pieces are created from The Rabbit Hole’s junkbox. Even the star of the show, a 3D printed Rabbit wasn’t immune. Many rabbits were printed for the stop motion animation process. As can be expected, there were a few failed prints. Those prints became Rabbit footed Lamps, Tables, and a rather macabre rabbit’s hand in a tray. Even the camera dolly was welded up from some scrap metal and old roller blade wheels.

We like the way the entire hackerspace was able to come together to create something greater than any one of them could have done alone. This sort of project should be a template for other hackerspaces to follow.

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VFD Display Becomes An Amplifier

November 9, 2013 by 15 Comments

Born well into the transistor era of the late 80s, [Fernando] missed out on all the fun you can have with high voltage and vacuum tubes. He wanted to experience this very cool tech, but since you won’t find a tube checker down at the five and dime anymore, where exactly do you get a vacuum tube to play around with? [Fernando]’s solution was to rip apart the vacuum fluorescent display from an old radio (Google Translate) and use that as a triode.

Inside every VFD is a filament, grid, and cathode – three simple elements also found in the triodes of just about every tube amp ever made. By applying a small voltage to the filament, a larger voltage to the cathode, and sending an audio signal to the grid, this triode amplifies the electrical signal coming from a stereo or guitar.

[Fernando] built his circuit on a breadboard, and with a little tweaking managed to get a fairly respectable amount of gain from parts salvaged from a radio. While using VFDs as amplifiers is nothing new – we’ve seen it a few times before, tube builds are always great to see, and bodged up electronics even more so.

Detect Disguises With A Raspberry Pi

November 9, 2013 by 17 Comments

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Computer vision based face detection systems are getting better every day. Authorities have been using face detection and criminal databases for several years now. But what if a person being detected is wearing a mask? High quality masks have been making their way out of Hollywood and into the mainstream. It isn’t too far-fetched to expect someone to try to avoid detection using such a mask. To combat this, [Neil] has created a system which detects face masks.

The idea is actually rather simple. The human face has a well-defined heat signature. A mask will not have the same signature. Even when worn for hours, a mask still won’t mimic the infrared signature of the human face. The best tool for this sort of job would be a high resolution thermal imaging camera. These cameras are still relatively expensive, so [Neil] used a Melexis MLX90620 64×8 16×4 array sensor. The Melexis sensor is interfaced to an Arduino nano which then connects to a Raspberry Pi via serial.

The Raspberry Pi uses a Pi camera to acquire an image. OpenCV’s face detection is then used to search for faces. If a face is detected, the data from the Melexis sensor is then brought into play. In [Neil’s] proof of concept system, a temperature variance over ambient is all that is needed to detect a real face vs a fake one. As can be seen in the video after the break, the system works rather well. Considering the current climate of government surveillance, we’re both excited and a bit apprehensive to see where this technology will see real world use.

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Transmitting Data With A Pi And RTL-SDR

November 9, 2013 by 31 Comments

Sometimes the best builds aren’t anything new, but rather combining two well-developed hacks. [Marc] was familiar with RTL-SDR, the $30 USB TV tuner come software defined radio, but was surprised no one had yet combined this cheap radio dongle with the ability to transmit radio from a Raspberry Pi. [Marc] combined these two builds and came up with the cheapest portable radio modem for the Raspberry Pi.

Turning the Raspi into a transmitter isn’t really that hard; it only requires a 20cm wire inserted into a GPIO pin, then toggling this pin at about 100 MHz. This resulting signal can be picked up fifty meters away, and through walls, even.

[Marc] combined this radio transmitter with minimodem, a program that generates audio modem tones at the required baud rate. Data is encoded in this audio stream, sent over the air, and decoded again with an RTL-SDR dongle.

It’s nothing new, per se, but if you’re looking for a short-range, low-bandwidth wireless connection between a computer and a Raspberry Pi, this is most certainly the easiest and cheapest method.

HHH: Delta CNC Mill

November 9, 2013 by 3 Comments

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[Dan] wrote in to show off the delta-bot CNC mill which he and some buddies got up and running over the course of about two weeks. The team from Mad Fellows — a hackerspace in Prescott, Arizona — put their heads together and managed to build the thing from mostly parts-on-hand. Would you believe they’re only out-of-pocket about $100 in new materials?

After a bit of modeling work they started scavenging for parts, recovering most of the acrylic stock from dead LCD monitors. But there are many parts like the stepper motors, precision rods, bearings, belts, and pulleys that can’t or shouldn’t be salvaged in order to end up with a reasonably solid machine tool. We like [Dan’s] tip that the parts should be screwed together as gluing them would be problematic when it comes time to replace broken components.

You may be wondering about the strength of a delta-bot for milling. The purpose of the build is to make molds for investment casting. The lost-material (we don’t know if it’s wax or something else) is quite easy to machine and you can see in the clip after the jump that the mill does a great job. But they also did some tests on aluminum and apparently it’s not a problem.

The CNC version of HHH is over, so why are we posting this now? We messed up. [Dan] sent in a qualifying entry before the deadline and somehow we let it slip through the cracks. Sorry [Dan]! Better late than never — we’ll get a T-shirt in the mail right away.

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