An Open Hardware Platform for ECG, EEG and Other Measurements

[Eric] tipped us about the OpenHarwareExG project which goal is to build a device that allows the creation of electrophysiological signal processing applications. By the latter they mean electrocardiography (ECG, activity of the heart), electroencephalography (EEG, signals on the scalp), electromyography (EMG, skeletal muscles activity), electronystagmography and electrooculography (ENG & EOG, eye movements) monitoring projects. As you can guess these signals are particularly hard to measure due to their small amplitude and therefore susceptibility to electrical noise.

The ADS1299 8-channel 24-bit analog front end used in this platform is actually electrically isolated from the rest of the circuit so the USB connection wouldn’t perturb measurements. An Arduino-compatible ATSAM3X microcontroller is used and all the board is “DIY compatible” as all parts can be sourced in small quantities and soldered by hand. Even the case is open source, being laser cut from acrylic.

Head to the project’s website to download all the source files and see a quick video of the system in action.

Interested in measuring the body’s potential? Check out an ECG that’s nice enough to let you know you have died, or this Android based wireless setup.


DIY Custom Molded Earbud Roundup

Headphones have become ubiquitous these days. Thanks to the iPod and the smartphone, it’s become commonplace to see someone wearing a pair of earbud style headphones. Earbuds aren’t always comfortable though. On some people they are too loose. On others, the fit is so tight that they cause pain.To that end, we’ve found a few great solutions for this problem.

[cptnpiccard] has documented his custom molded Sugru earbuds in an Imgur gallery. He’s molded a pair of standard earbuds into a cast of his ear. He uses them both for hearing protection and tunes while skydiving. Sugru’s FAQ states that while the cured material is safe for skin contact (and in ear use) some people are sensitive to the uncured material.

While discussing his project on Reddit, a few users chimed in and mentioned they’ve made custom molded earbuds using Radians custom earplug kits. The Radians material hardens up in only 10 minutes, which beats waiting an hour for Sugru.

The absolute top of the food chain has to be building your own triple driver in ear monitors, which is exactly what [marozie] has done. Professional custom molded monitors can cost over $1000, which puts them in the realm of professional musicians and audiophiles. [marozie] discovered that mouser stocks quite a few transducers from Knowles. These tiny speakers don’t come cheap, though; you can spend upwards of $70 just for a single driver.

[marozie] took a cast of his ear using an earmold impression kit. He used this cast to create a mold. From there it was a matter of pouring resin over his carefully constructed driver circuits and audio tubes. The resulting monitors look and sound incredible.

It goes without saying that making custom in ear monitors involves putting chemicals into you ears. The custom earmold kits come with tiny dams to keep the mold material from going in too far and causing damage. This is one of those few places where we recommend following the instructions. Click past the break to see a demo video of the ear molding process.

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Gutenberg Clock Keeps Time by Reading Books

Gutenberg clock displaying text from a book

We’ve seen a wide variety of hacks that keep time, but [ch00f]‘s latest build takes a new spin on counting the seconds. The Gutenberg Clock keeps time by reading books on a scrolling LED screen.

The content for the clock is sourced from the Project Gutenberg, which releases books with expired copyright for free. The library on the clock consists of around twenty thousand such books. Read at eighty words per minute, the clock won’t repeat a passage for the next thirty-three years.

While the clock doesn’t display time itself, it is synchronized to time. Two identical clocks should display the same text at the same time. To get the time, [ch00f] first tried hacking apart a cheap radio clock, which is synchronized to NIST’s 60 kHz broadcast. After reverse engineering the protocol with great success, stray RF energy from the display turned out to cause too much interference.

With the cheap solution out the window, [ch00f] built a custom breakout for an Adafruit GPS module and used it to get the time. This was his first RF board, but it worked out fine.

Books are loaded onto a FAT filesystem on an SD card, and [ChaN]‘s FatFS is used to interpret the filesystem. A microcontroller then sends the text out at a constant rate to a serial port on the display which he hacked his way into.

The project is a neat mix of art and electronics. Stick around for a video overview after the break.

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VR Bowling Game Combines an Oculus Rift with a Wii Remote

d [marclar83] was given an Oculus Rift so that he could prepare for an upcoming conference presentation. He began to download demos, getting familiar with the VR interface but was disappointed to find out that someone hadn’t developed a good virtual reality bowling experience yet. This prompted him to design a VR game that integrates a Wii Remote, recording the movements of the controller and sending accelerometer data to his computer.

The game he created is similar to Wii Sports Bowling but with the added bonus of being immersed in a virtual world with the Oculus Rift. The D-pad on the Wii Remote was programmed to switch stances and bowling methods, allowing the user to choose whether they want to throw the ball down the middle or curve it a long the way. Pressing the trigger button on the back started the swinging motion, and when released, the bowling ball shot down the alley at a high rate of speed crashing into the pins at the end.

Because the game was designed on the original DK1, the resolution of the images was a challenge that needed to be addressed, but [marclar83] solved this problem by implementing two user interfaces on the side of the screen that showed replays and depicted how many pins remained; proving to be a better experience for the gamer. This free public alpha version was made available for Windows, Mac, and Linux on the official VRBowling website. A video describing the project can be seen below. [Read more...]

Hydroforming in the Garage with a Pressure Washer

metal pillow

Ever heard of hydroforming? It’s a manufacturing process used to form sheet metal into shapes using water at extremely high pressures. Not something you can do at home… unless of course you’re [Colin Furze].

Hydroforming works by evenly distributing pressure via water (conveniently, in-compressible) against sheet metal inside of a mold. Many automotive parts are created in this fashion. Typical systems run at around 15,000 PSI.

After building a giant pulse jet engine (complete with butt) to fart on France, [Colin] got the idea from a YouTube comment to try to do hydroforming at home — bending the sheet metal for the giant derriere wasn’t that easy. Hydroforming on the other hand is a surprisingly simple process. Weld some sheet metal together, add a pipe fitting to connect your cheap pressure washer and boom — hydoformed metal parts.

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Hackerspace Tours: Pasadena City College

Pasadena City College is putting together an amazing combination of tools, education techniques, and innovative projects pinning them on the map as one of the best hackerspaces in the Southern California area. Led by [Deborah Bird], the Director of the Design Technology Pathway at PCC, and Sandy Lee the DTP Faculty Chair, this Fab Lab provides students with cutting-edge workshops and internships that will define future jobs.

We were invited to the space by Joan Horvath, the VP of Business Development over at a local 3D printing store called Deezmaker, after meeting her at an Arduino electronics class taught by a young, talented maker named [Quin]. When we arrived, we were greeted by several students who were working on a 3D printed portable map for the blind which was created for an elementary school nearby. The team behind the design attempted to step out of the visual world and into unfamiliar unsighted territory. One of the members gave us a tour of the space showing us the tools and resources they had made available to PCC students. A variety of 3D printers, ventilators, CNC machines, laser cutters, metal lathes, and even a chainsaw were found inside.

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A Homemade Bubble Robot for the Kids


Kids generally can be amused pretty easily, but when jangling keys stop holding their interest you might want to take a look at [drenehtsral]‘s new project. He’s created an automatic bubble robot (YouTube link) that keeps the kids endlessly entertained!

The project started as an idea at a festival where one of [drenehtsral]‘s kids took great interest at a bubble machine. [drenehtsral] had never heard of a bubble machine before, but it turns out that it’s pretty simple in practice. All that’s required is a tank of soapy water, a motor to turn the bubble wands, and a fan to form the bubbles and make them waft gently through the air.

[drenehtsral] also used a 12V battery for power, some other hardware to hold it all together, and a 5V regulator and some other control electronics for the fan and the motor. He notes that he could have bought a bubble machine but in true hacker style found it fun to build himself. The next step in this project could be something to vary the size of the bubbles, or perhaps a set of wheels for the robot so it can entertain the kids on the move!

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