3D Printing Binaural Microphones

Binaural audio is probably the coolest thing you can listen to with a pair of headphones. Instead of just a single microphone, binaural recordings use two microphones, set inside an analog for a human head, to replicate exactly what you would hear if you were there.

The only way to record binaural audio is with fake plastic ears attached to a dummy head. Most of the famous microphone manufacturers have something like this, but with a 3D printer, anything is possible. [Carlos] created his own binaural microphone using a 3D printer and went through the trouble of creating a few audio demos. The results are weird, like [Carlos] is whispering into your ear.

The ears used in this microphone setup are taken from a Thingiverse project by [Jonathan March]. This model did not properly model the ear canal,and didn’t have any way to mask the sound from ear to ear; this is why the professional models also include a head. [Carlos] fixed these shortcomings and created a few 3D models that accurately model the human ear and head.

There’s also a simple stereo microphone amplifier for this project that is designed to fit right between the ears. This amplifier was designed in KiCAD, and the PCB is single sided. It’s not quite simple enough to assemble on a piece of stripboard, but [Carlos] did manage to manufacture it on some copper clad board in his mill.

The results? It sounds awesome. [Carlos] put together a demo of his microphone, link below, and it only works if you’re wearing headphones.

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Codename Colossus: The HMC Boudicca

[Michael Sng], founder of [Machination Studio], wanted to create a toy line unlike anything the world has seen.  He has recently completed the first production prototype in the Codename Colossus toy line: the HMC Boudicca. The egg-shaped HMC Boudicca is tank-like with a definite Metal Slug vibe, but it’s almost a disservice calling it a toy.

The HMC Boudicca is over 20″ tall. It is composed of over 400 parts, a majority of which are 3D-printed or laser-cut. Internal parts are FDM while the external pieces are SLS printed. It is a kinetic piece that walks in a hexapodal fashion, so there are lots of servos, motors, sensors, and LEDs, that are controlled by an Arduino. A lot of work and attention to detail was put into this prototype. The HMC Boudicca was designed to be easily disassembled with a Phillips screwdriver. The electronic components are all plug-in devices, so no soldering is required when it comes time to replace a sensor or servo.

Codename Colossus is a toy line that is made to order and intended to be artisanal in nature. Each piece will be individually hand-painted and assembled like the HMC Boudicca. While no official prices are posted yet on the site, we assume these are not going to be cheap. In fact, the site states that each piece will have a 2% markup from the previously sold price to help maintain the value of the pieces and control cost inflation. This could be a source of contention for potential buyers. It underscores [Michael’s] philosophy that Codename Colossus is meant to be a collectible work of art, an antithesis to mass production.

Regardless of the business strategy, we are interested in seeing any additional designs for this series. It would be fun to see a whole bunch of these marching as one robot army!

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Machine Metal With Electricity: An EDM Attachment For 3D Printers

[SuperUnknown] has revealed a secret project he’s been working on. He’s cooked up an EDM attachment for 3D printers, or any CNC machine for that matter. Electrical Discharge Machining (EDM) is a method of using sparks to machine metal. EDM isn’t a new technology, in fact commercial machines have been around since the 1960’s. If you’ve ever had an arc scar up your multimeter probes, you’ve unwittingly done a bit of EDM.

The theory behind EDM is simple: High voltage between the tool and workpiece causes sparks to jump between them. Each spark erodes the workpiece (and the tool). Big EDM machines perform their magic in a liquid which acts as both a dielectric and a flushing medium. This liquid can be anything from deionzed tap water to specially formulated oil. [SuperUnknown] is using good old-fashioned tap water.

edm-roughAs you can imagine, a single spark won’t erode much metal. EDM machines fire tens of thousands of times per second. The exact frequencies, voltages, and currents are secrets the machine manufacturers keep close to their chests. [SuperUnknown] is zeroing in on 65 volts at 2 amps, running at 35 kHz. He’s made some great progress, gouging into hardened files, removing broken taps from brass, and even eroding the impression of a coin in steel.

While we’d love to say this is a free open source project, [superUnknown] needs to pay the bills. He’s going with crowdsourced funding. No, not another Kickstarter. This project is taking a different route. The videos of the machine will be uploaded to YouTube and visible to [superUnknown’s] Patreon supporters. They will also be available for rent using YouTube’s new rental system. [SuperUnknown] has pledged to figure out a way to make the content available for starving college students and others with limited incomes.

Based upon his previous adventures with lil’ screwy, his homemade 100 ton press, and various other projects on the Arduino verses Evil YouTube channel, we think [superUnkown] has a pretty good chance of making home EDM work. Click past the break to see two videos of the 3D printer EDM toolhead in action. We should mention that [SuperUnknown] is rather colorful with his dialogue, so make sure you’re using headphones if you’re at work.

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Making A Bobblehead Of You

Bobbleheads, you remember them, small figures with a spring-mounted comically large head. They brought joy to millions of car drivers every day as at least 97.5% of all registered cars in the 1960’s had bobbleheads mounted to the dash. Years later bobblehead popularity has waned but [Luis] is trying to bring them back, this time not as your iconic sports hero but as YOU!

[Luis] uses software called Skanect along with his Kinect to scan a persons geometry. There is a free version of Skanect but it is limited to exporting STL files no larger than 5,000 faces. That means that 3d printed bobbleheadscans of large objects (including people) come out looking noticeably faceted. [Luis] came up with a work-around that results in a much finer detailed scan. Instead of scanning an entire person with one scan, he would do 4 separate scans. Since each individual scan can support 5,000 faces, the resulting merged model can be up to 20,000 faces. Check out the comparison, the difference between the two scanning methods is quite noticeable. MeshMixer is the software used to merge the STL files of the 4 separate scans.

Once the full body is assembled in MeshMixer, it is time to separate the head from the body. A cylindrical hole is then made in the bottom of the head and the top of the body. This hole is just slightly larger than the spring used to support the head. The parts are then printed, painted and assembled. We have to say that the end result looks pretty darn good.

Delta 3D Printer Made From Unorthodox Parts

Over here at Hackaday, we love stuff made from other (unrelated) stuff. Maybe it’s the ingenuity behind the build or the recycling of parts… or it could be both. Either way, it’s cool and a side benefit of re-using parts from the junk drawer is that it keeps the project cost down, maybe enough that the project wouldn’t even be feasible without the re-use of parts.

That brings us to the topic of this post, a Delta-style 3D Printer made from recycled parts not typically seen in such a machine. It was built by DIYer [hesamh] and is almost unrecognizable visually. The usual extruded aluminum or precision shaft frame has been replaced with 5 pieces of MDF, finger-jointed together at the seams. Attached to the 3 vertical MDF frame pieces are rail and carriage assemblies scavenged from Epson dot matrix prints saved from the scrap yard. The best part is that these rail/carriage assemblies already had stepper motors and belts installed!

The end effector is also unique among delta-style printers. This one is made from aluminum plate and provides a mount for the extruder. There is no need for a bowden tube setup when the extruder is mounted on the end effector, although the increase in mass may reduce the printer’s top speed. That’s fine by us as we’d rather have a good-looking slow print than a fast ball of spaghetti. Another scavenged stepper motor is used for the extruder. The accompanying belt pulley acts as a direct drive feed gear.

The print bed is a re-purposed flatbed scanner. The guts were removed and a heating element was placed under the glass. The bed heater is controlled separately by way of a household thermostat. An Arduino Leonardo and 4 stepper drivers replace the normally used Mega/RAMPS/Pololu combo. Overall, this is a cool build that shows what is possible with a little thought and resourcefulness. The only part used in this build that was actually made for use in a 3D Printer is the hotend!

Rise of Hardware: A PCH Hackathon

Over the weekend, I had the pleasure of helping out at the KW Hackathon in Waterloo, Ontario, sponsored by PCH Hardware, who hosts hackathons and meetups around the world to help inspire invention and entrepreneurship. This was the sixth hardware based hackathon they have hosted.

When they host a hackathon, they gather local sponsors and provide the tools and resources for the entrants to actually develop a working prototype in less than 54 hours, that they then can pitch to a panel of judges to win some awesome prizes. Did we mention it’s free to register? The next one is in London, England.

Personally, I provided some mentorship in product design and development, but more importantly, I opened up the use of my giant laser cutter to help the teams create real prototypes, and learn more about rapid prototyping using a laser cutter. Everyone wanted to 3D print their prototypes at first — but there was a limited number of printers available, and long wait times. We introduced them to sites like www.makercase.com, a site that will generate laser cutter plans for enclosures that you specify the dimensions of, and of course, the ability to search google for “laser cut arduino case” to find pre-designed laser designs for electronics.

Some teams more experienced in CAD got creative and made cool decahedrons which actually helped create a working prototype the way they envisioned it on paper.

PCH-Hackathon-for-Communitech-Day-2-496

In addition to the main event, they hosted keynote speakers and workshops to help take teams ideas even further — we think Communitech (the hosting venue) really summed up the purpose of having hackathons nicely:

“Useful stuff does really emerge from hackathons: some realized ideas, but more importantly, new human hacker connections and a deeper sense of capability and our capacity to create beyond the software realm.”

Overall, the event was fantastic, and it makes us wish there were more like it. You could feel the buzz of excitement in the room when creative people got together and started designing and making things. Oh and the free food was pretty awesome too — especially for students.

For more information about the event, check out the news piece by [Darin White] for Communitech News.

Prevent Failed Prints With A Filament Speed Sensor

If you have used a 3D printer for any length of time, you’ve probably experienced a failed print caused by a clogged nozzle. If you’re not around to stop the print and the nozzle stays hot and full of filament for hours, the clog gets even worse. [Florian] set out to solve this issue with an encoder that measures filament speed, which acts as an early warning system for nozzle clogs.

static1.squarespace.com[Florian] designed a small assembly with a wheel and encoder that measures filament movement. The filament passes under the encoder wheel before it’s fed into the 3D printer. The encoder is hooked up to an Arduino which measures the Gray code pulses as the encoder rotates, and the encoder count is streamed over the serial port to a computer.

When the filament slows down or stops due to a nozzle clog, the Python script plays a notification sound to let you know that you should check your nozzle and that your print might fail. Once [Florian] works out some of the kinks in his setup, it would be awesome if the script could stop the print when the nozzle fails. Have any other ideas on how to detect print failures? Let us know in the comments.