3D Scanning Rig And DIY Turntable

May 23, 2015 by Rich Bremer 11 Comments

It seems almost every day 3D scanning is becoming more and more accessible to the general DIYer. The hardware required is minimal and there are several scanning softwares and workflows to choose from. However, if you have slowly walked around a subject while holding a Kinect and trying to get a good scan, you know this is not an easy task. A quick internet search will result in several DIY scanning setup solutions that have been cobbled together and lack substantial documentation…. until now! [aldricnegrier] is fighting back and has designed and documented a rotary table that will spin at a constant speed while a subject is 3D scanned, making person scanning just that much easier.

The project starts off with a plywood base with a Lazy Susan bearing assembly attached to the top. The Lazy Susan supports the rotating platform for the subject person to stand on, but it’s not just a platform, it’s also a huge gear! The platform teeth mesh with a much smaller 3D printed gear mounted on the shaft of a DC motor and reduction gearbox assembly.

Another goal of the project was to make the rotary table autonomous. There is an ultrasonic sensor mounted to the base aimed above the rotating platform. The ultrasonic sensor is connected to an Arduino and if the system senses someone or something on the platform for 3 seconds, the Arduino will command a DC motor driver to start spinning the platform.

As cool as this project is so far, [aldricnegrier] wanted to make it even cooler: he added speech recognition. Using Microsoft’s Speech Toolkit, saying the words ‘Start Skanect‘ will start the scanning process on the PC. Now, a sole person can scan themselves easily and reliably.

[aldricnegrier] has made all of his CAD files, STL files and Arduino code available so anyone wanting to build this clearly capable setup can do so!

Pictures That Defeat Key Locks

May 23, 2015 by Mike Szczys 65 Comments

We’re at LayerOne this weekend and one of the talks we were excited about didn’t disappoint. [Jos Weyers] presented Showing Keys in Public — What Could Possibly Go Wrong? The premise is that pictures of keys, in most cases, are as good as the keys themselves. And that pictures of keys keep getting published.

[Jos] spoke a bit about new services that offer things like 3D scanning and storage of your key for printing when you get locked out, or apps that ask you to take a picture of your key and they’ll mail you a duplicate. Obviously this isn’t the best of ideas; you’re giving away your passwords. And finding a locksmith is easier than findind a 3D printer. But it’s the media gaffs with important keys that intrigues us.

We’ve already seen the proof of concept for taking covert images to perfectly duplicate a key. But these examples are not so covert. One example is a police officer carrying around handcuff keys on a belt clip. Pose for a picture and that key design is now available to all. But news stories about compromised keys are the biggest offenders.

A master key for the NYC Subway was compromised and available for sale. The news coverage not only shows a picture at the top of the story of a man holding up the key straight on, but this image of it on a subway map which can be used to determine scale. This key, which is still published openly on the news story linked above, opens 468 doors to the subway system and these are more than just the ones that get you onto the platform for free. We were unable to determine if these locks have been changed, but the sheer number of them has us thinking that it’s unlikely.

Worse, was the availability of fire-department ~~master~~ keys ~~which open lock boxes outside of every building~~. (Correction: these are fire department keys but not the actual lock-box keys) A locksmith used to cut the original keys went out of business and sold off all their stock. These keys were being sold for $150, which is bad enough. But the news coverage showed each key on a white background, straight on, with annotations of where each type of key will work.

Other examples include video news stories about credit card skimmers installed in gas pumps — that coverage showed the key used to open the pump housing. There was also an example of speed camera control cabinet keys being shown by a reporter.

[Jos’] example of doing the right thing is to use a “prop” key for news stories. Here he is posing with a key after the talk. Unfortunately this is my own house key, but I’m the one taking pictures and I have blurred the teeth for my own security. However, I was shocked during image editing at the quality of the outline in the image — taken at 6000×4000 with no intent to make something that would serve as a source for a copy. It still came out remarkably clear.

Some locks are stronger than others, but they’re all meaningless if we’re giving away the keys.

Hacklet 48 – Weather Sensing Projects

May 23, 2015 by Adam Fabio 21 Comments

Throughout history, mankind has been at the mercy of the weather. Planning a major outdoor event like a wedding or a naval battle? Better hope for clear skies! Man doesn’t have the ability to change mother nature at will quite yet, but hackers are working on it! Until then, we can measure the current conditions and predict the weather in the near future. A bit of help from cloud based computer models and global sensing even allows us to model and predict weather patterns days in advance. It’s no surprise that makers, engineers, and hackers love weather projects. We’ve found there are two basic project groups (with a some overlap between them): Sensing projects and display projects. This week’s hacklet focuses on some of the best weather sensing projects on Hackaday.io!

We start with [diysciborg] and Modular Weather Station. This 2014 Hackaday Prize entrant is a DIY outdoor weather station. [diysciborg] went with easily available PVC pipe and sheet metal for most of his mechanical build. His anemometer alone is a work of art. Mounting 8 magnetic reed switches in slots cut in a PCB allows for a thin device which can easily sense the speed of the wind. Other sensors include a TLS230R light to frequency converter for sunlight measurement, CO, wind direction, and more. An Arduino Pro Mini is at the center of it all.

[Clovis Fritzen] is saving the planet from global warming with his project FacilTempo. FacilTempo is a weather station, and an entry in the 2015 Hackaday Prize. The idea is to make a simple and low-cost setup which can be built in bulk and placed anywhere on the Earth. [Clovis] plans to measure temperature, humidity, atmospheric pressure, sunlight, and rain. He also hopes to add a Sparkfun sensor to monitor wind speed and direction. All the data will be transmitted via a radio link. [Clovis] is adding the ability for FacilTemp to communicate via 433 MHz, WiFi, or Bluetooth. The entire sensor suite and its on-board ATmega328 will be powered by a LiPo battery. The battery will be charged by solar or wind power, depending upon what is available on site. With 8 project logs already in the can, FacilTempo is well on its way to beating back global warming!

[Ulf Winberg] is building the Low Cost Weather Station, his entry in the 2015 Hackaday Prize. Low Cost Weather Station aims to be a $50 sensor suite for local weather conditions. [Ulf] plans to power the entire device using wind and solar energy. He’s hoping to avoid batteries by storing his power in a supercapacitor. Power calculations have been taking up quite a bit of his design time so far. The $50 bill of materials limit is one that [Ulf] is serious about. He’s keeping careful eye on his component selections to keep that goal attainable. The system will transmit wind speed, wind direction, sun, and other data through a Laird BL600 Bluetooth low energy transceiver.

Finally we have [Greg Miller] taking it back to basics with Weather Station Zeta. Zeta is [Greg’s] first big project. He’s only just recently learned to solder, but he’s already squeezing a lot of performance out of a little Arduino. The idea is to create a two station system. The outdoor station will monitor the weather, including temperature, humidity, and barometric pressure. Data will be transmitted to an indoor station with a similar set of sensors. The indoor station will also include a 20 line x 4 column character LCD to display the data. [Greg] has the indoor section of the system just about done, and he’s working on learning the ins and outs of XBee data radios. He’s also going to include an Adafriut CC3000 breakout board to Web enable the weather station. We love seeing ambitious early projects like this one!

If you want to see more projects like these, check the Weather Sensing Projects list on Hackaday.io.

That’s it for this week’s Hacklet, As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Finally, VR For Four Eyes

May 23, 2015 by Brian Benchoff 30 Comments

In the next few years, VR headsets will be everywhere, and everyone will slowly recede into their own little reality that is presented on high-resolution displays right in front of their eyes. One specific group will be left out: eyeglass wearers. VR just doesn’t work with eyeglasses, and a few people in Germany are fixing this problem. They’re creating custom prescription lenses for Google Cardboard, giving anyone with glasses the opportunity to look just a little more hipster.

The folks behind this Indiegogo already run a specialty optics shop in Germany. They have the tools to make custom lenses for spectacles, and they’re the first company so far that has identified a problem with the current crop of VR headsets and has created a solution. The campaign is for a set of lenses that can be attached to Google Cardboard with double stick tape. There are limitations on how strong of a prescription they can make, but it should work for most four eyes.

It should be noted this Indiegogo isn’t the only way to get custom lenses for a VR headset. If you have your prescription, there are a few places to buy glasses online for $30 or so. Do that, remove the lenses from the frame, and affix them to Cardboard.

From Broken Drill Bit To Knife: Backyard Forging Basics

May 23, 2015 by James Hobson 21 Comments

One of our tipsters sent in a great video showing how to make knives out of old broken drill bits. It comes from [The Art of Weapons] YouTube channel which is run by a 15 year old from the UK. He’s applying old techniques to modern technology and it’s awesome to see someone young with these skills.

The beauty of this hack is aside from the tools you’ll need, it’s practically free to do. Worn out drill bit or other steel tool? No problem – heat it up and make something new. At the heart of this build is making your own forge. There’s lot of options, from using firebricks, to making a soup can forge like he did. From there, it’s really just a matter of annealing the steel (heating it up to red hot, and letting it cool down slowly in sand), and then heating it up again and forming it with a hammer and anvil.

But he doesn’t stop there: he also shows us his method of making handles for knives out of hardwood — its a pretty cool process and the finished knives are beautiful. The video below is a bit long, but well worth the watch if you’re interested in trying your own hand at forging.

Continue reading “From Broken Drill Bit To Knife: Backyard Forging Basics” →

Hackaday Fail: A $3000 Prototype That Doesn’t Work

May 23, 2015 by Brian Benchoff 113 Comments

[Dan Royer] is hard at work building his own personal robot army. Robots mean motors, and motors mean gearboxes. In [Dan]’s case, gearboxes mean $3000 wasted on a prototype that doesn’t work. Why doesn’t it work? He doesn’t know, and we don’t either.

[Dan] would like to use small but fast DC motors for his robots coupled to a gearbox to step down the speed and increase the torque. The most common way of doing this is with a planetary gear set, but there’s a problem with the design of planetary gears – there is inherent backlash and play between the gears. This makes programming challenging, and the robot imprecise.

A much better way to gear down a small DC motor is a hypocycloid gear. If you’ve ever seen the inside of a Wankel engine, this sort of gearing will look very familiar: a single gear is placed slightly off-axis inside a ring gear. On paper, it works. In reality, not so much.

[Dan] spent $3000 on a prototype hypocycloid gearbox that doesn’t turn without binding or jamming. The gear was made with incredible tolerances and top quality machining, but [Dan] has a very expensive paper weight sitting on his desk right now.

If anyone out there has ever designed or machined a hypocycloid gearbox that works, your input is needed. The brightest minds [Dan] met at the Bring A Hack event at Maker Faire last weekend could only come up with. ‘add more lasers’, but we know there’s a genius machinist out there that knows exactly how to make this work.

Hackaday Fail is a column which runs every now and again. Help keep the fun rolling by writing about your past failures and sending us a link to the story — or sending in links to fail write ups you find in your Internet travels.

Hackaday Prize Entry: Biopotential Signal Library

May 22, 2015 by Brian Benchoff 11 Comments

With prosthetics, EEG, and all the other builds focused on the body and medicine for this year’s Hackaday Prize, it might be a good idea to take a look at what it takes to measure the tiny electrical signals that come from the human body. Measuring brain waves or heartbeats indoors is hard; AC power frequencies easily couple to the high impedance inputs for these measurements, and the signals themselves are very, very weak. For his entry to The Hackaday Prize, [Paul Stoffregen] is building the tools to make EEG, ECG, and EMG measurements easy with cheap tools.

If the name [Stoffregen] sounds familiar, it’s because he’s the guy behind the Teensy family of microcontroller boards and several dozen extremely popular libraries for everything from displays to real time clocks. The biopotential signal library continues in [Paul]’s tradition of building very cool stuff with just code.

The hardware used in this project is TI’s ADS1294, a 24-bit ADC with either 4 or 8 channels. This chip is marketed as a medical analog front end with a little bit of ECG thrown in for good measure. [Paul] is only using the ADS1294 initially; more analog chips can be added later. It’s a great project in its own right, and when you include the potential applications of this library – everything from prosthetics to body sensors – it makes for an awesome Hackaday Prize entry.