OpenSurgery Explores The Possibility Of DIY Surgery Robots

August 14, 2016 by Gerrit Coetzee 31 Comments

As the many many warnings at the base of the Open Surgery website clearly state, doing your own surgery is a very bad idea. However, trying to build a surgery robot like Da Vinci to see if it can be done cheaply, is a great one.

For purely academic reasons, [Frank Kolkman] decided to see if one could build a surgery robot for less than an Arab prince spends on their daily commuter vehicle. The answer is, more-or-less, yes. Now, would anyone want to trust their precious insides to a 3D printed robot with dubious precision? Definitely not.

The end effectors were easily purchased from a chinese seller. Forty bucks will get you a sterile robotic surgery gripper, scissor, or scalpel in neat sterile packaging. The brain of the robot is basically a 3D printer. An Arduino and a RAMPS board are the most economical way to drive a couple steppers.

The initial version of the robot proves that for around five grand it’s entirely possible to build a surgery robot. Whether or not it’s legal, safe, usable, etc. Those are all questions for another research project.

The Quest For Mice With Frickin’ Laser Beams (Pointed At Their Brains), Building A Laser Controller

August 13, 2016 by Gerrit Coetzee 16 Comments

The logo for the field is kind of cute though.

[Scott Harden] is working on a research project involving optogenetics. From what we were able to piece together optogenetics is like this: someone genetically modifies a mouse to have cell behaviors which can activated by light sensitive proteins. The mice then have a frikin’ lasers mounted on their heads, but pointing inwards towards their brains not out towards Mr. Bond’s.

Naturally, to make any guesses about the resulting output behavior from the mouse the input light has to be very controlled and exact. [Scott] had a laser and he had a driver, but he didn’t have a controller to fire the pulses. To make things more difficult, the research was already underway and the controller had to be built

The expensive laser driver had a bizarre output of maybe positive 28 volts or, perhaps, negative 28 volts… at eight amps. It was an industry standard in a very small industry. He didn’t have a really good way to measure or verify this without either destroying his measuring equipment or the laser driver. So he decided to just build a voltage-agnostic input on his controller. As a bonus the opto-isolated input would protect the expensive controller.

The kind of travesty that can occur when [Stefan Kiese] doesn't have access to nice project boxes. — The kind of travesty that can occur when [Scott] doesn’t have access to nice project boxes.

The output is handled by an ATtiny85. He admits that a 555 circuit could generate the signal he needed, but to get a precision pulse it was easier to just hook up a microcontroller to a crystal and know that it’s 100% correct. Otherwise he’d have to spend all day with an oscilloscope fiddling with potentiometers. Only a few Hackaday readers relish the thought as a relaxing Sunday afternoon.

He packaged everything in a nice project box. He keeps them on hand to prevent him from building circuits on whatever he can find. Adding some tricks from the ham-radio hobby made the box look very professional. He was pleased and surprised to find that the box worked on his first try.

A Trove Of 3D Printer Filament Test Data

August 13, 2016 by Gerrit Coetzee 9 Comments

We’re not sure what a typical weekend at [Walter]’s house is like, but we can probably safely assume that any activity taking place is at minimum accompanied by the hum of a 3D printer somewhere in the background.

Those of us who 3D print have had our experiences with bad rolls of filament. Anything from filament that warps when it shouldn’t to actual wood splinters mixed in somewhere in the manufacturing process clogging up our nozzles. There are lots of workarounds, but the best one is to not buy bad filament in the first place. To this end [Walter] has spent many hours cataloging the results of the different filaments that have made it through his shop.

We really enjoyed his comparison of twleve different yellow filaments printed side by side with the same settings on the same printer. You can really see the difference high dimensional tolerance, the right colorant mix, and good virgin plastic stock makes to the quality of the final print. Also, how transparent different brands of transparent actually are as well as the weight of spools from different brands (So you can weigh your spool to see how much is left).

The part we really liked was his list every filament he’s experienced in: PLA, ABS, PETG, Flexible, Nylon, Metal, Wood, and Other. This was a massive effort, and while his review is naturally subjective, it’s still nice to have someone else’s experience to rely on when figuring out where to spend your next thirty dollars.

Almost Fail Of The Week: Doing Surface Mount Reflow Wrong In Every Possible Way And Still Succeeding

August 12, 2016 by Gerrit Coetzee 34 Comments

Sometimes the best way to learn is from the success of others. Sometimes failure is the best teacher. In this case we are learning from [Tim Trzepacz]’s successive failures in his attempt to solder one board to another using a reflow oven. They somehow cancelled each other out, and he ended up with a working board. For those of you who have used a reflow oven, there will be eye rolling.

[Tim]’s first mistake was to use regular solder instead of paste. We can see how he got there logically; if you hand solder an SMD you melt solder onto the pads first to make it easier. However, the result was that he had two boards that wouldn’t sit flat on each other thanks to the globs of solder on the pads.

Not to be deterred, he laid the boards on top of each other and warmed up the oven to a toasty 650 degrees. Well, not quite. The dang oven didn’t turn to eleven, so he figured 500 would probably work too. Missing the hint entirely, he let his board bake in a nearly 1000F oven until he noticed some smoke which, he intuitively knew, definitely shouldn’t be happening.

The board was blackening, the solder mask was literally bubbling off the substrate, people were coming over to see the show, and he decided success was still possible. He clamped the heated boards together with a binder clip until they cooled. Someone gave him a lesson on reflow, presumably listened to through reddening ears.

Ashamed and defeated, he went home. However, there was a question in his mind. Sure it looks bad, but is it possible that the board actually works? After a quick test, the answer was yes. It loaded some code and an time later he was happily hacking away. Go figure.

Technically A Hack. Still Questionable. Remote Control Food.

August 12, 2016 by Gerrit Coetzee 23 Comments

We thought we were going to read an article about, perhaps, a quadcopter that could fetch beer, or donuts. What we got was more along the lines of a donut dragging itself across the floor, rendering it pitiful and advisibly indigestible.

Sometimes people joke about not wanting to get in mind of a crazy person. We understand. While we could certainly follow [Michael Kohn]’s logic, the motivation was alien. Either way, in a rare turn of events there was not a single Arduino to be seen; just reverse engineering, unique solutions, and even a custom board. This is what some of you have been asking for… we think.

The brain of the questionable contraption is a TI MSP430G2231 and a tiny forward only motor driver circuit. The MSP waits for a signal from a hacked IR remote control from a cheap RC car. It then turns those into the appropriate motor control signals which go to some of those nice tiny metal gearboxes.

There were, naturally, a lot of technical issues in mounting the electronics to the food that, well… they didn’t need to be solved, but they were solved. For example, masking tape apparently does not stick well to green peppers, so toothpicks must be employed to pin the tape in place. Hopefully knowledge like this is scheduled for the nightly wipe while we sleep, but we’ll probably hold onto it till we die, unlike expensive piano lessons.

In the end we had a good laugh, and the idea is so dumb it will probably be an educational Kickstarter next week. Video after the break.

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Stick Balances Itself With Reaction Wheels

August 11, 2016 by Gerrit Coetzee 33 Comments

The inverted pendulum is a pretty classic dynamics problem and reaction wheels are cool. That’s why we like [Mike Rouleau]’s self-balancing stick.

The video, viewable after the break, was fairly sparse on details, but he furnished some in the comments. The little black box on the top is a GY-521 Gyroscope module. It sends its data to an Arduino attached to the black cord which trails off the screen. The Arduino does its mathemagic and then uses a motor controller to drive the reaction wheels at the correct speeds.
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Drones, Clever Hacks, And CG Come Together For Star Wars Fan Film

August 11, 2016 by Gerrit Coetzee 12 Comments

We weren’t certain if this Star Wars fan film was out kind of thing until we saw the making of video afterwards. They wanted to film a traditional scene in a new way. The idea was to take some really good quadcopter pilots, give them some custom quadcopters, have them re-enact a battle in a scenic location, and then use some movie magic to bring it all together.

The quadcopters themselves are some of those high performance racing quadcopters with 4K video cameras attached. The kind of thing that has the power to weight ratio of a rocket ship. Despite what the video implies, they are unfortunately not TIE Fighter shaped. After a day of flying and a few long hikes to retrieve the expensive devices after inevitable crashes (which, fortunately, provided some nice footage), the next step was compositing.

However, how to trick the viewer into believing they were in a X-Wing quadcopter? A cheap way to do it would be to spend endless hours motion tracking and rendering a cockpit in place. It won’t look quite real. The solution they came up with is kind of dumb and kind-of brilliant. Mount a 3D printed cockpit on a 2×4 with a GoPro. Play the flight footage on a smartphone while holding the contraption. Try to move the cockpit in the same direction as the flight. We’re not certain if it was a requirement to also make whooshing and pew pew laser noises while doing so, but it couldn’t hurt.

In the end it all came together to make a goofy, yet convincingly good fan film. Nice work! Videos after the break.

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