When 18-year-old Honduran maker Luis Cruz met a quadriplegic high school classmate and learned about the challenges he and other folks with disabilities face in the light of expensive assistive communication technologies, he was inspired to devise a solution. What Luis came up with is the Eyeboard: an inexpensive yet reliable human-computer interface that detects eye movements using electrooculography (EOG), a biomedical technique based on picking up signals from electrodes placed around the eyes, which in this case enables users who can’t manipulate a mouse or trackpad to move a cursor on a screen. Luis wrote about his project in an eye tracking feature on the pages of MAKE Volume 29, alongside Zach Lieberman’s EyeWriter project. Here is Luis’ article on the Eyeboard design and development:
The eyeball generates a voltage of 0.4mV–1.0mV (millivolts) between its cornea in front and retina in back. If you attach electrodes on opposite sides of the eye, they’ll pick up some of this voltage, depending on where the eyeball is pointing. Looking straight ahead, with the cornea and retina equidistant between the electrodes, there will be no voltage. But with the eyeball angled to one side, you can measure a microvolt-level signal between the
electrodes nearer the cornea and the one opposite. EOG can track both horizontal and vertical movements, but horizontal is easier and more useful. My system, like many others, only tracks horizontal using 3 electrodes: one right next to each eye,and the ground electrode centered on the bridge of the nose or forehead.
A processor chip or even an oscilloscope cannot detect such small voltages, so the EOG system must amplify them, while also filtering out any noise from nearby electrical devices and wiring. You can see the circuit I built to accomplish this, along with step-by-step instructions for building my EOG system and programming its microcontroller chip, at makeprojects.com.
To amplify the signal initially, I use an INA118 instrumentation amplifier chip configured with a 100Ω resistor between pins 1 and 8, which gives it a gain of 501. The INA118 chip’s high CMRR (common-mode rejection ratio) of 110dB eliminates common signals that go into both inputs, which removes some noise at the start of the signal path.
Noise from electrode circuits tends to come at high frequencies, so mine uses 2 passive low-pass filters in sequence, to reduce this noise above their cutoff frequency of around 16Hz. With the circuit I used, the formula for the cutoff is 1 /2πRC, where R is resistance and C is capacitance, so with a 100kΩ resistor and a 0.1µF cap, this comes out to 15.9Hz, which is fine; eye movements aren’t so fast that filtering cuts out anything important.
Finally, a capacitor zeroes the signal by removing the DC offset added by the resting potential between the eyes, and a voltage follower circuit lets you connect a higher source impedance device than the EOG output’s impedance, which is useful to connect an oscilloscope or multimeter for troubleshooting. To power the system, I use two 7805 voltage regulators wired in a trick way to supply the circuit with +5V, –5V, and ground (0V), eliminating the need for a dual power supply.
To process the amplified signal when the eyes move horizontally, I feed it into the analog-digital converter pin of an AT-mega328P microcontroller that’s programmed to send the data to a computer via serial port. A Python script on the computer then sends the data to a C++ applet I wrote, which lets the user spell out messages. Looking to the left scrolls down through letters, and looking to the right selects them. To make wearing the electrodes more comfortable, I mounted them to some glasses modded with a headband and super glue. I’ve built several prototypes of these EOG glasses with good results.
I’m still improving this EOG system, including looking for ways to make it more comfortable to wear. I’m pleased to have developed a system for less than $200 that enables disabled people, like my classmate, to communicate, when commercial versions of the same cost a minimum of $10,000. I’d also like to create inexpensive EOG-interface systems for other applications, such as controlling a wheelchair or a television. I just graduated from high school, and what I need most of all in order to pursue these ideas is a scholarship, sponsor, or other funding source so that I can study electrical engineering in the United States.
Here’s the Reuters coverage of Luis’ project from December 2011:
Build your own Eyeboard by following the instructions Luis shared on Make: Projects.
From the pages of MAKE Volume 29:
We have the technology (to quote The Six Million Dollar Man), but commercial tools for exploring, assisting, and augmenting our bodies really can approach a price tag of $6 million. Medical and assistive tech manufacturers must pay not just for R&D, but for expensive clinical trials, regulatory compliance, and liability — and doesn’t help with low pricing that these devices are typically paid for through insurance, rather than purchased directly. But many gadgets that restore people’s abilities or enable new “superpowers” are surprisingly easy to make, and for tiny fractions of the costs of off-the-shelf equivalents. MAKE Volume 29, the “DIY Superhuman” issue, explains how.
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As reported here on MAKE last year by Jon Kalish, Marina 59′s “Boatel” in Far Rockaways, Queens, NYC is expanding their programming this summer with a six-week boat-maker residency. They’ve just launched an Open Call for artists & makers to submit your ideas; deadline is March 9, and small stipends are available. The best part is they have abandoned boats they are looking to salvage/renovate, so the difficult part of actually building a boat is already taken care of! Managed in part by some of the Swimming Cities crew, the residency seeks to address access to NYC’s water, boat maker and building skills, and build community in the Far Rockaways, an often overlooked area of the boroughs. So whether you’re looking to refurbish a watercraft, meet some new boat enthusiasts, or simply work all day and enjoy the tranquility of the marina at night, details are online here.
The Boatel is a fleet of refurbished abandoned boats clustered around a floating platform. Some of our newly salvaged boats are gutted, others have existing interiors. Design proposals should consider functionality. The structural integrity of the boats should not be compromised. Artists will be able to stay part-time or full-time in a boat with water & electricity for the duration of the project. The beach is five blocks away. You are also welcome to bring a kayak or canoe to explore Jamaica Bay, or use one of ours.
[Click on the headline above to see the entire photo gallery]
Last night I enjoyed the monthly Pecha Kucha event in San Francisco (pronounced pe-CHA-k’cha, quickly). It’s like Dorkbot for designers, but with a format similar to Ignite events. Each presenter has 20 slides that show for 20 seconds each, and advance automatically. The event took place at the Children’s Creativity Museum (formerly, Zeum), and the theme was “Creating outside the lines.”
Here Are Some Highlights:
- Cartoonist Nick Dragotta, who draws Howtoons in MAKE magazine, talked about DIY comics and demonstrated the classic Marshmallow Shooter project that appeared in MAKE Volume 02. Dragotta explained that he and the other Howtoons collaborators avoid being didactic. They never say “here, do this,” but instead integrate the how-to information into the storytelling. The Howtoons cartoons are anthologized in two books, and because the first book includes cartoons showing power tools, the publisher was afraid of having it shelved in the Children’s section of bookstores– so it went into the adult Science instead.
- Designer Alberto Villareal showed how he and some pals turned some misprinted books into skateboard decks, by cutting the pages out, folding and weaving them together, then encasing them in resin. Originally they just poured the resin over the paper, but the result was too flexible, so they made a fiberglass mold of a skateboard deck and cast the paper and resin inside. The resulting skateboard is heavier and more flexible than a plywood skateboard.
- Balloon artist Brian Asman presented his work and explained that, after seeing the play R. Buckminster Fuller: The History (And Mystery) Of The Universe, he was inspired to develop a tetrahedron balloon element. It was so strong that it became the basis for a full-size balloon sofa that adults can sit on.
- Artist Jenny Chapman described her public sculpture Manifest Destiny! (in collaboration with Mark Reigelman), for which a small steel-framed log cabin was grafted four stories high onto the side of the Hotel des Artes building in San Francisco. She also described her Bridge Equality project, which seeks to make a political cause of temporarily switching the paint colors between the Golden Gate and Oakland Bay bridges.
- Furniture maker Dylan Gold showed some of his amazing designs, eliciting gasps from the audience. He described M. C. Escher as an early influence, and recounted his career trajectory from commercial graphic artist to woodworker. (Photo: Garry McLeod)
- Sam Haynor described what it’s like to help kids develop their own inventions at the Mission Science Workshop, a makerspace for underprivileged youth. He said that the empowerment of things like drill presses and chain saws is unparallelled in the kids’ lives, and observed that the fourth grade is about the age that kids start crossing out their own drawings because they didn’t turn out right. One example invention he helped a kid with was The Farting Poopunator, a device conceived to collect farts and poo from the user, for throwing at enemies. Using this example, Haynor explained how the process of invention and hands-on development with children is more important than the end product.
Fun! Pecha Kucha events take place in dozens of cities, and are expanding to more locations with support from Autodesk.
Conductive Ink from Jordan Bunker
There are so many cool projects out there that use conductive ink, but where to get the ink? Now you can DIY that part, too!
Jordan Bunker of Pumping Station: One in Chicago embarked on this chemistry project and documented the UIUC process into easy-to-follow instructions.
Conductive inks have a myriad of different interesting applications. As a quick, additive construction method for electronic circuits, they are especially intriguing. Unfortunately, for a long time they have been just out of reach of the hobby market. They are too expensive to buy in decent quantities, too complicated to make, too resistive to be practical, or require high annealing temperatures (which would ruin many of the materials you’d want to put traces on).
Now, thanks to some brilliant minds at the UIUC Materials Research Laboratory, you can make your own decent conductive ink!
As with most things worth doing, there are risks.
NOTE: Please don’t do this at home unless you understand the risks and dangers and know how to avoid them. In fact, it’s best that you have a chemist or someone experienced with how to handle chemicals properly help you.
Ammonium hydroxide is nasty stuff. Formic Acid is even worse (It’s basically liquid pain. It’s the chemical in ant bites and bee stings that makes them hurt). Please respect this stuff.
See the material list, full process, and trial and error on Jordan’s post.
Drawing Circuits in Conductive Ink