Using a Theremin for Medical Applications

theremin

[Eswar] is not an ordinary 16 years old boy. He figured out a noninvasive way to measure breathing in hospitals for less than $50. He is using a theremin to measure the rise and fall of a patient’s chest. For our curious readers, this touch-less instrument was invented back in 1929 by the Russian inventor [Leon Theremin]. It uses the heterodyne principle and two oscillators to generate an audio signal. One electronic oscillator creates an inaudible high pitch tone while another variable oscillator is changed by adding capacitance to an antenna.

As you can guess the space between the patient’s chest and the antennas placed around the bed forms a tiny capacitor which varies when exhaling. With three simple TTL chips and a little guessing [Eswar] had a working prototype ready to be implemented in the real world. If you’re interested in theremin, we invite you to see one of our previous articles on how to make one in a few minutes with a soda can.

THP Semifinalist: fNIR Brain Imager

565281406845688681 The current research tool du jour in the field of neuroscience and psychology is the fMRI, or functional magnetic resonance imaging. It’s basically the same as the MRI machine found in any well equipped hospital, but with a key difference: it can detect very small variances in the blood oxygen levels, and thus areas of activity in the brain. Why is this important? For researchers, finding out what area of the brain is active in response to certain stimuli is a ticket to Tenure Town with stops at Publicationton and Grantville.

fMRI labs are expensive, and [Jeremy]‘s submission to The Hackaday Prize is aiming to do the same thing much more cheaply, and in a way that will vastly increase the amount of research being done with this technique. How is he doing this? Using the same technology used in high-tech vein finders: infrared light.

[Jeremy]‘s idea is much the same as a photoplethysmograph, better known as a pulse oximeter. Instead of relatively common LEDs, [Jeremy] is using near infrared LEDs, guided by a few papers from Cornell and Drexel that demonstrate this technique can be used to see blood oxygen concentrations in the brain.

Being based on light, this device does not penetrate deeply into the brain. For many use cases, this is fine: the motor cortex is right next to your skull, stretching from ear to ear, vision is taken care of at the back of your head, and memories are right up against your forehead. Being able to scan these areas noninvasively with a device you can wear has incredible applications from having amputees control prosthetics to controlling video game characters by just thinking about it.

[Jeremy]‘s device is small, about the size of a cellphone, and uses an array of LEDs and photodiodes to assemble an image of what’s going on inside someone’s head. The image will be somewhat crude, have low resolution, and will not cover the entire brain like an fMRI can. It also doesn’t cost millions of dollars, making this one of the most scientifically disruptive entries we have for The Hackaday Prize.

You can check out [Jeremy]‘s intro video below.


SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize. 

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3D Printing a Beautiful Prosthetic Hand for a Stranger

3D Printed Prosthetic Hand

Here’s a story that made us feel all warm and tingly on the inside. [Evan Kuester] is currently studying his Masters in Architecture with a specialty in digital fabrication. His program has access to some nice 3D printers, and he was itching for a good project to use them for. Why not a 3D printed prosthetic hand?

He got the idea after noticing a fellow student on campus who was missing her left hand, and did not have any kind of prosthetic. Eventually he worked up the nerve to introduce himself to her and explain his crazy idea. She thought it was brilliant.

Using Rhino, [Evan] began modeling the prosthetic hand using a plugin called Grashopper. He wanted the hand to be functional as well as aesthetically pleasing, so he spent quite a while working with [Ivania] to make it just right. His first prototype, the Ivania 1.0 wasn’t quite what he imagined, so he redesigned it to what you see above. It’s a beautiful mixture of engineering and art, but unfortunately the fingers don’t move — perhaps an improvement for version 3.0? Regardless of functionality, [Ivania] loves it.

Oh, and [Evan] and [Ivania] are close friends now — in case you were wondering.

[via Make]

[Bil's] Quest for a Lost Finger: Episode I

A little over a year ago I had a semi-gruesome accident; I stepped off of a ladder and I caught my wedding ring on a nail head. It literally stripped the finger off the bone. This was in spite of me being a safety-freak and having lived a whole second life doing emergency medicine and working in trauma centers and the like. I do have trauma center mentality which means, among other things, that I know you can’t wind the clock back. A few seconds make an incredible differences in people’s lives. Knowing that it couldn’t be undone, I stayed relaxed and in the end I have to say I had a good time that day as I worked my way through the system (I ended  up in a Philadelphia trauma center with a nearby hand specialist) as I was usually the funniest guy in the room. Truth be told they ask incredibly straight questions like”are you right handed?”  “Well I am NOW”.

hand9 So now I could really use a bit of a body hack, having seen the X-Finger on Hackaday long before I knew that I would one day work with them, I was hoping that we could get one to work for me. In speaking with a couple of the mechanical engineers on the Hackaday staff we decided to get [James Hobson] and [Rich Bremer] involved and that the best way to do it was to get a casting of my injured hand out to them.

 

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Hacking out of Necessity — Fixing Your Own CPAP Machine

Fixing a CPAP machine

One of our avid readers named [Felix] suffers from sleep apnea, and needs a CPAP machine in order to not suffocate while he sleeps — After a recent power-outage, his machine broke, so he decided to try his hand at fixing it.

A CPAP (Continuous Positive Airway Pressure) machine ensures people suffering from sleep apnea breath throughout the night, by preventing their throats from closing. As a medical device, they tend to be super expensive, which is why [Felix] wanted to try fixing his (at least until he gets a new machine covered by insurance).

Upon opening up the machine, it was easy to see the problem: the circuit board was completely fried. Luckily, the machine is pretty simple. It has a brushless DC motor (12V), and two chambers with air filters, along with an air pressure sensor. Since the motor is brushless, it’s not quite as simple as just hooking it up to a power supply. It had a whopping 8 separate leads.

[Read more...]

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.

 

Backyard Brains: Controlling Cockroaches, Fruit Flys, And People

[Greg Gage] and some of the other crew at Backyard Brains have done a TED talk, had a few successful Kickstarters, and most surprisingly given that pedigree, are actually doing something interesting, fun, and educational. They’re bringing neuroscience to everyone with a series of projects and kits that mutilate cockroaches and send PETA into a tizzy.

[Greg] demonstrated some of his highly modified cockroaches by putting a small Bluetooth backpack on one. The roach had previously been ‘prepared’ by attaching small electrodes to each of its two front antennas. The backpack sends a small electrical signal to the antennae every time I swiped the screen of an iPhone. The roach thinks it’s hitting a wall and turns in the direction I’m swiping, turning it into a roboroach. We seen something like this before but it never gets old.

Far from being your one stop shop for cockroach torture devices, Backyard Brains also has a fairly impressive lab in the basement of their building filled with grad students and genetically modified organisms. [Cort Thompson] is working with fruit flies genetically modified so a neuron will activate when they’re exposed to a specific pulse of light. It’s called optogenetics, and [Cort] has a few of these guys who have an ‘I’m tasting something sweet’ neuron activated when exposed to a pulse of red light.

Of course controlling cockroaches is one thing, and genetically engineering fruit flies is a little more impressive. How about controlling other people? After being hooked up to an EMG box to turn muscle actuation in my arm into static on a speaker, [Greg] asked for a volunteer. [Jason Kridner], the guy behind the BeagleBone, was tagging along with us, and stepped up to have two electrodes attached to his ulnar nerve. With a little bit of circuitry that is available in the Backyard Brains store, I was able to control [Jason]‘s wrist with my mind. Extraordinarily cool stuff.

There was far too much awesome stuff at Backyard Brains for a video of reasonable length. Not shown includes projects with scorpions, and an improved version of the roboroach that gives a roach a little bit of encouragement to move forward. We’ll put up a ‘cutting room floor’ video of that a bit later.

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