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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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.

Embedding PCBs In 3D Prints

The folks over at Lunchbox Electronics are working on a very cool prototype: embedding LEDs inside standard 1×1 Lego bricks. Being a prototype, they needed a cheap way to produce Lego bricks stuffed with electronics. It turns out a normal 3D printer has okay-enough resolution, but how to put the electronics in the bricks? Gcode wizardry, of course.

3d-printed-LEGO-w-pcb-thumbThe electronics being stuffed into the bricks isn’t much – just a small PCB with an LED. It does, however, need to get inside the brick. This requires stopping the 3D printer at the right layer, moving the print head out of the way, inserting the PCB, and moving the head back to where it stopped.

Gcode to the rescue. By inserting a few lines into the Gcode of the print, the print can be paused, the print head raised and returned, and the print continued.

If you want to check out what these light up Lego look like, There’s a Kickstarter happening now. It’s exactly what the 80s space sets needed, only thirty years late.

Hackaday Prize Entry: Welding Plastic Filament

There are a lot of neat toys and accessories that rely on 3D printing filament. The 3Doodler is a 3D printing pen, or pretty much an extruder in a battery-powered portable package. You can make your own filament with a Filastruder, and of course 3D printers themselves use up a lot of filament. [Bodet]’s project for this year’s Hackaday Prize gives those tiny scraps of leftover filament a new life by welding filament together.

The EasyWelder [Bodet] is designing looks a little bit like a tiny hair straightener; it has a temperature control, a power switch, and two tips that grip 1.7 or 3mm diameter filament and weld them together. It works with ABS, PLA, HIPS, Nylon, NinjaFlex, and just about every other filament you can throw at a printer. By welding a few different colors of filament together, you can create objects with different colors or mechanical properties. It’s not as good as dual extrusion, but it does make good use of those tiny bits of filament left on a mostly used spool.

Since the EasyWelder can weld NinjaFlex and other flexible filaments, it’s also possible to weld NinjaFlex to itself. What does that mean? Custom sized O-rings, of course. You can see a video of that below.


The 2015 Hackaday Prize is sponsored by:

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Need Custom Parts? This Week We’re Giving Out $2k In 3D Printing

We’re having an excellent time watching your project builds take shape. All summer long we’re giving away prizes to make this easier and to help move great prototypes along. Last week we offered up 125 Teensy-LC boards; the winners are listed below. This week we want to see interesting parts come to life so we’re giving away two-thousand dollars in 3D Printing.

These 3D printed parts will be delivered to 40 different project builds in the form of $50 gift cards from Shapeways. Basically, you just design your parts, choose a printing medium like plastic or metal, and before you know it your digital creation appears as a real part shipped in the mail.

Time to write down your Hackaday Prize idea and get it entered! You’re best chance of winning will come when you publish a new project log describing how having custom-printed parts would move your build forward. Whether or not you score something this week, you’ll be eligible for all the stuff we’re giving away this summer. And of course, there’s always that Grand Prize of a Trip into Space!

Last Week’s 125 Winners of a Teensy-LC Board

50k-in-play-teensy-lc-featured

Congratulations to these 125 projects who were selected as winners from last week. You will receive a Teensy-LC board. The name makes them sound small, but the ARM Cortex-M0+ packs a punch. 62k of flash, 8k of RAM, and these run at up to 48 MHz. Program them bare-metal or use the ease of the Arduino IDE. Don’t forget to post pictures and information about what you build using your newly acquired powerhouse!

Each project creator will find info on redeeming their prize as a message on Hackaday.io.


The 2015 Hackaday Prize is sponsored by:

Printing Photorealistic Images On 3D Objects

Hydrographic Printing is a technique of transferring colored inks on a film to the surface of an object. The film is placed on water and activated with a chemical that allows it to adhere to an object being physically pushed onto it. Researchers at Zhejiang University and Columbia University have taken hydrographic printing to the next level (pdf link). In a technical paper to be presented at ACM SIGGRAPH 2015 in August, they explain how they developed a computational method to create complex patterns that are precisely aligned to the object.

Typically, repetitive patterns are used because the object stretches the adhesive film; anything complex would distort during this subjective process. It’s commonly used to decorate car parts, especially rims and grills. If you’ve ever seen a carbon-fiber pattern without the actual fiber, it’s probably been applied with hydrographic printing.

print_tThe physical setup for this hack is fairly simple: a vat of water, a linear motor attached to a gripper, and a Kinect. The object is attached to the gripper. The Kinect measures its location and orientation. This data is applied to a 3D-scan of the object along with the desired texture map to be printed onto it. A program creates a virtual simulation of the printing process, outputting a specific pattern onto the film that accounts for the warping inherent to the process. The pattern is then printed onto the film using an ordinary inkjet printer.

The tiger mask is our personal favorite, along with the leopard cat. They illustrate just how complex the surface patterns can get using single or multiple immersions, respectively. This system also accounts for objects of a variety of shapes and sizes, though the researchers admit there is a physical limit to how concave the parts of an object can be. Colors will fade or the film will split if stretched too thin. Texture mapping can now be physically realized in a simple yet effective way, with amazing results.

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MRRF: Hot Ends, Extruders, Extremely Posh Brits, And Stoic Swedes

As far as locations for the Midwest RepRap Festival go, it’s not exactly ideal. This is a feature, not a bug, and it means only the cool people come out to the event. There were a few people travelling thousands of miles across an ocean, just to show off some cool things they built.

Two Colors, One Nozzle

[Sanjay] and [Josh] from E3D came all the way from merry olde England to show off a few of their wares. The star of their show was the Cyclops extruder, a dual-extrusion hot end that’s two input, one output. Yes, two colors can come out of one nozzle.

cyclops

If you see a printer advertised as being dual extrusion, what you’re going to get is two extruders and two hot ends. This is the kludgy way to do things – the elegant solution is to make two colors come out of one nozzle.

The guys from E3D were showing off a few prints from their Cyclops nozzle that does just that, including a black and red poison dart frog, and a blue and white octopus. The prints looked amazing, and exactly what you would expect from a two-color print.

Rumor has it the development of the Cyclops involved extruding two colors, freezing the nozzle, and putting it in the mill just to see how the colors mixed. I didn’t see those pictures, but there’s a lot of work that went into this hot end.

The Power of Two Extruders

[Martin] of bondtech.se came to MRRF all the way from Sweden. He was there showing off his new extruder.

The extruder uses a normal stepper motor, but instead of the usual knurled or threaded feed wheel and bearing to push filament though, he’s using two counter-rotating feed wheels attached to a planetary gear system. That’s a lot of torque that doesn’t distort or strip the filament. When you consider all the weird filaments that are coming out – ninjaflex, and even 3D printable machinable wax filament, this is extremely interesting.

Even if your filament isn’t exactly 1.75 or 3mm in diameter, this setup will still reliably push plastic; there is a bolt that will move one of the feed wheels in and out 0.4mm.

[Martin] had a pair of his extruders hooked up to a strain gauge, and it’s strong enough to lift your printer off the table without stripping the filament. Here’s a video of that demo from the bondtech page.