Husband Uses MRI Images To 3D Print Wife’s Skull And Tumor

January 17, 2015 by 35 Comments

[Michael Balzer] shows us that you are your own best advocate when it comes to medical care – having the ability to print models of your own tumors is a bonus. [Michael’s] wife, Pamela, had been recovering from a thyroidectomy when she started getting headaches. She sought a second opinion after the first radiologist dismissed the MRI scans of her head – and learned she had a 3 cm tumor, a meningioma, behind her left eye.  [Michael], host of All Things 3D, asked for the DICOM files (standard medical image format) from her MRI.  When Pamela went for a follow-up, it looked like the tumor had grown aggressively; this was a false alarm. When [Michael] compared the two sets of DICOM images in Photoshop, the second MRI did not truly show the tumor had grown. It had only looked that way because the radiologist had taken the scan at a different angle! Needless to say, the couple was not pleased with this misdiagnosis.

However, the meningioma was still causing serious problems for Pamela. She was at risk of losing her sight, so she started researching the surgery required to remove the tumor. The most common surgery is a craniotomy: the skull is sawed open and the brain physically lifted in order to access the tumor below it. Not surprisingly, this carries a high risk of permanent damage to any nerves leading to loss of smell, taste, or sight if the brain is moved the wrong way. Pamela decided to look for an alternative surgery that was less invasive. [Michael] created a 3D print of her skull and meningioma from her MRIs. He used InVesalius, free software designed to convert the 2D DICOM files into 3D images. He then uploaded the 3D rendered skull to Sketchfab, sharing it with potential neurologists. Once a neurologist was found that was willing to consider an alternative surgery, [Michael] printed the skull and sent it to the doctor. The print was integral in planning out the novel procedure, in which a micro drill was inserted through the left eyelid to access the tumor. In the end, 95% of the tumor was removed with minimal scarring, and her eyesight was spared.

If you want to print your own MRI or CT scans, whether for medical use or to make a cool mug with your own mug, there are quite a few programs out there that can help. Besides the aforementioned InVesalius, there is DeVIDE, Seg3D, ImageVis3D, and MeshLab or MeshMixer.

Twisted String Actuators

January 17, 2015 by 39 Comments

[Travis] tells us about a neat actuator concept that’s as old as dirt. It’s capable of lifting 7kg when powered by a pager motor, and the only real component is a piece of string.

The concept behind the twisted string actuator, as it’s known to academia, is as simple as putting a motor on one end of a piece of string, tying the other end off to a load, and putting a few twists in the string. It’s an amazingly simple concept that has been known and used for thousands of years: ballistas and bow-string fire starters use the same theory.

Although the concept of a twisted string actuator is intuitively known by anyone over the age of six, there aren’t many studies and even fewer projects that use this extremely high gear ratio, low power, and very cheap form of linear motion. A study from 2012 (PDF) put some empirical data behind this simple device. The takeaway from this study is that tension on the string doesn’t matter, and more strands or larger diameter strands means the actuator shrinks with a fewer number of turns. Fewer strands and smaller diameter strands take more turns to shrink to the same length.

As for useful applications of these twisted string actuators, there are a few projects that have used these systems in anthropomorphic hands and elbows. No surprise there, really; strings don’t take up much space, and they work just like muscles and tendons do in the human body.

Thanks [ar0cketman] for the link.

Vacuum Tube

Vacuum Tube Repair After A Spectacular Failure

January 17, 2015 by 33 Comments

[Eric] has an Atwater Kent 55C AM radio from the early 1900’s. He’s been trying to restore the radio to proper working condition. His most recent pain has been with the rectifier tube. The tube is supposed to have a complete vacuum inside, but that’s not the case here. When the tube is powered up, it glows a beautiful violet color. It may look pretty, but that’s indicative that gas has leaked into the tube. It needed to be replaced.

[Eric] had a tube that would serve as a good replacement, but it’s plug didn’t fit the socket properly. He was going to have to use this old broken tube to make an adapter. Rather than just tearing the old tube apart, he decided to have some fun with it first. He hooked it up to a variac, an ammeter, and a volt meter. Then he slowly increased the voltage to see what would happen. The result was visually stunning.

The tube starts out with the same violet/blue glowing [Eric] experienced previously. As the voltage increases, it gets more and more intense. Eventually we start to see some green colors mixing in with the violets. [Eric’s] reaction to this unexpected result is priceless. As the tube gets increasingly hot, the anode starts glowing an orange-red color. Finally, the filament starts to crackle like a sparkler before the tube just gives up and completely fails.

After the light show, [Eric] moves on to replacing the tube. He begins by tapping on the old tube’s socket with the end of a screwdriver. After much tapping, the glass starts to come lose from the socket. After a bit of wiggling and twisting the tube finally came free from the socket. [Eric] luckily had an unused octal socket that fit perfectly inside of the old socket. All he needed to do to build his adapter was to connect the four pins from the old adapter to the proper pins on the octal socket. Piece of cake.

…Or so [Eric] thought. After testing some new tubes with a tube tester, he realized he had soldered all four pins incorrectly. On top of that, he had super glued the adapter together. He eventually got the two pieces apart. This time he removed all of the unused pins from the octal socket so he wouldn’t get it wrong. Another run on the tube tester confirmed that everything looked good. After plugging the tube into the radio, it worked just as expected

If you need fabrication rather than repair, we’ve got you covered there as well. Check out [Charles Alexanian’s] process for making new vacuum tubes in his garage. Now if you just have too darn many of them around, you can always decorate your pad with ’em.

Continue reading “Vacuum Tube Repair After A Spectacular Failure” →

Dial

Dial Is A Simple And Effective Wireless Media Controller

January 17, 2015 by 26 Comments

[Patrick] was looking for an easier way to control music and movies on his computer from across the room. There is a huge amount of remote control products that could be purchased to do this, but as a hacker [Patrick] wanted to make something himself. He calls his creation, “Dial” and it’s a simple but elegant solution to the problem.

Dial looks like a small cylindrical container that sits on a flat surface. It’s actually split into a top and bottom cylinder. The bottom acts as a base and stays stationary while the top acts as a dial and a push button. The case was designed in SOLIDWORKS and printed on a 3D printer.

The Dial runs on an Arduino Pro mini with a Bluetooth module. The original prototype used Bluetooth 2.0 and required a recharge after about a day. The latest version uses the Bluetooth low energy spec and can reportedly last several weeks on a single charge. Once the LiPo battery dies, it can be recharged easily once plugged into a USB port.

The mechanical component of the dial is actually an off-the-shelf rotary encoder. The encoder included a built-in push button to make things easier. The firmware is able to detect rotation in either direction, a button press, a double press, and a press-and-hold. This gives five different possible functions.

[Patrick] wrote two pieces of software to handle interaction with the Dial. The first is a C program to deal with the Bluetooth communication. The second is actually a set of Apple scripts to actually handle interaction between the Dial and the various media programs on his computer. This allows the user to more easily write their own scripts for whatever software they want. While this may have read like a product review, the Dial is actually open source! Continue reading “Dial Is A Simple And Effective Wireless Media Controller” →

Postage Scale

Fixing A Broken Postage Scale

January 16, 2015 by 7 Comments

[Starhawk] had an old Pitney Bowes G799 postage scale that wasn’t working as it should. After years of faithfully measuring packages and cooking ingredients, the scale stopped working. At first it fell out of calibration. Then the power up sequence stopped working. The scale normally would turn on, light up the entire display, then change to dashes, and finally set itself to 0.0 lbs. In this case, it would get stuck at the dashes and never change to 0.0.

[Starhawk] ended up purchasing another duplicate scale from eBay, only to find that when it arrived it had the exact same power up problem. Using deductive reasoning, he decided that since the scale was broken during shipping the problem would likely be with a mechanical component. He turned out to be correct. The cheap momentary power button was at fault. When pressing the button, the contact would get stuck closed preventing the scale from zeroing out properly. [Starhawk] easily fixed his problem by replacing the switch.

Next [Starhawk] replaced the old scale’s LCD module with one from the new scale, since the old one looked to be on its way out. The scale still had a problem correctly measuring weight. [Starhawk] tried swapping the load cell from the new scale to the old one, but he found that the new load cell had some kind of problem that prevented the scale from zeroing out properly. The solution ended up being to use the newer “analog board” as [Starhawk] calls it.  The end result was the old scale with two newer circuit boards, an older load cell, and a new power switch. Next time it might be easier to just build his own scale.

Simple Pen Plotter

Simple DIY Pen Plotter, Great First CNC Project

January 16, 2015 by 10 Comments

[Morten] has been busy recently making a pen plotter. It is a simple and elegant build that he completely designed from the ground up. There are no extra frivolous parts here. The frame is made from laser-cut plexiglass which makes fabrication easy if you have access to a laser cutter. Two NEMA17 motors are responsible for the machine’s movement. One moves the pen carriage back and forth by way of a belt. The other is connected by laser-cut gears to a roller bar, scavenged from an ink jet printer, that moves the paper media forward and aft underneath the pen.

The software chain used here is sort of uncommon compared to other inexpensive DIY CNC machines we see here on Hackaday. [Morten] creates his geometry with Rhino, then uses a plugin called Grasshopper to generate the g-code that controls the machine. That g-code is sent using gRemote to an Arduino flashed with the contraptor.org g-code interpreter. A RAMPS board takes the step and direction signals generated by the Arduino and moves the two stepper motors appropriately.

In typical open-supporting fashion, [Morten] has made his design files freely available for anyone to download. His plotter moves the pen side to side and the paper front to back in order to draw shapes but that’s not the only way a plotter can work. Check out this polar plotter and this one that hangs.

Check out the video after the break…

Continue reading “Simple DIY Pen Plotter, Great First CNC Project” →

Alarm1

Adding WiFi And SMS To An Alarm System

January 16, 2015 by 17 Comments

[Don] wanted to bring his alarm system into the modern age. He figured that making it more connected would do the trick. Specifically, he wanted his alarm system to send him an SMS message whenever the alarm was tripped.

[Don] first had to figure out a way to trigger an event when the alarm sounds. He found a screw terminal that lead to the siren. When the alarm is tripped, this screw terminal outputs 12V to enable the siren. This would be a good place to monitor for an alarm trip.

[Don] is using an Arduino nano to monitor the alarm signal. This meant that the 12V signal needed to be stepped down. He ran it through a resistor and a Zener diode to lower the voltage to something the Arduino can handle. Once the Arduino detects a signal, it uses an ESP8266 WiFi module to send an email. The address [Don] used is the email-to-SMS address which results in a text message hitting his phone over the cell network.

The Arduino also needed power. [Don] found a screw terminal on the alarm system circuit board that provided a regulated 12V output. He ran this to another power regulator board to lower the voltage to a steady 5V. This provides just the amount of juice the Arduino needs to run, and it doesn’t rely on batteries. [Don] provides a good explanation of the system in the video below. Continue reading “Adding WiFi And SMS To An Alarm System” →