A Pulse Oximeter From Very Little

May 16, 2020 by Jenny List 31 Comments

Against the backdrop of a global respiratory virus pandemic, it’s likely that more than a few readers have been thinking about pulse oximeters. You may even have looked at one closely and seen that it’s little more than a device which shines light through your finger, and wondered how they work. It’s something [Giulio Pons] has done, and to show us how it’s done he’s created a working pulse oximeter of his own.

He started with an infra-red heartbeat sensor module, which is revealed as nothing more than an IR LED and a photodiode. Sampling the output from the photodiode allows measurement of heartbeat, but gives not clue as to oxygen saturation. The interesting part comes via the property of red light in that it’s transmission through flesh varies with oxygen saturation, so adding a red LED and alternately measuring from the IR and red illuminations allows a saturation figure to be derived.

Commercial pulse oximeters are pretty cheap, so many of us will no doubt simply order one from the usual sources and call it good. But it’s always interesting to know how any device works, and this project reveals something simpler than we might have expected. If pulse oximeters interest you, compare it with this one we featured a few years ago.

Aladdin Lamp Shoots Flames With A Snap Of Your Fingers

May 13, 2020 by Moritz v. Sivers 4 Comments

Despite their dangers, even Marie Kondo would not convince us to abandon flamethrower projects because they literally spark joy in us. To make this flame shooting Aladdin lamp [YeleLabs] just used a 3D printer and some basic electronics.

The lamp body consists of two 3D-printed halves held together by neodymium magnets. They house a 400 kV spark generator, a fuel pump plus tank, and a 18650 Li-ion battery. The fuel pump is actually a 3 V air pump but it can also pump liquids at low pressure. As fuel [YeleLabs] used rubbing alcohol that they mixed with boric acid to give the flame a greenish tint. The blue base at the bottom of the lamp houses the triggering mechanism which magically lights up the lamp when you snap your fingers. This is achieved by a KY-038 microphone module and KY-019 relay module connected to a Digispark ATTiny85 microcontroller. When the microphone signal is above a certain threshold the relay module will simultaneously switch on the spark generator and fuel pump for 150 ms.

Although they proclaim that the device is a hand sanitizer it is probably safer to stick to using soap. The project still goes on the list of cool flamethrower props right next to the flame shooting Jack-o-Lantern.

Video after the break.

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A Smart Bandage For Monitoring Chronic Wounds

May 12, 2020 by Orlando Hoilett 4 Comments

Here at Hackaday, we’re always enthralled by cool biohacks and sensor development that enable us to better study and analyze the human body. We often find ourselves perusing Google Scholar and PubMed to find the coolest projects even if it means going back in time a year or two. It was one of those scholarly excursions that brought us to this nifty smart bandage for monitoring wound healing by the engineers of FlexiLab at Purdue University. The device uses an omniphobic (hydrophobic and oleophobic) paper-based substrate coupled with an onboard impedance analyzer (AD5933), an electrochemical sensor (the same type of sensor in glucometers) for measuring uric acid and pH (LMP91000), and a 2.4 GHz antenna for wirelessly transmitting the data (nRF24L01). All this is programmed with an Arduino Nano. They even released their source code.

To detect uric acid, they used the enzyme uricase, which is very specific to uric acid and exhibits low cross-reactivity with other compounds. They drop cast uric acid onto a silver/silver chloride electrode printed on the omniphobic paper. Similarly, to detect pH, they drop cast a pH-responsive polymer called polyaniline emeraldine salt (PANI-ES) between two separate silver/silver chloride electrodes. All that was left was to attach the electrodes to the LMP91000, do a bit of programming, and there they were with their own electrochemical sensor. The impedance analyzer was a bit simpler to develop, simply attaching un-modified electrodes to the AD5933 and placing the electrodes on the wound.

The authors noted that the device uses a much simpler manufacturing process compared to smart bandages published by other academics, being compatible with large-scale manufacturing techniques such as roll-to-roll printing. Overcoming manufacturing hurdles is a critical step in getting your idea into the hands of consumers. Though they have a long way to go, FlexiLab appears to be on the right track. We’ll check back in every so often to see what they’re up to.

Until then, take a look at some other electric bandage projects on Hackaday or even make your own electrochemical sensor.

Portable MRI Machine Comes To The Patient

May 8, 2020 by Dan Maloney 41 Comments

To say that the process of installing a magnetic resonance imager in a hospital is a complex task is a serious understatement. Once the approval of regulators is obtained, a process that could take years, architects and engineers have to figure out where the massive machine can be installed. An MRI suite requires a sizable electrical service to be installed, reinforced floors to handle the massive weight of the magnet, and special shielding in the walls and ceiling. And once the millions have been spent and the whole thing is up and running, there are ongoing safety concerns when working around a gigantic magnet that can suck ferromagnetic objects into it at any time.

MRI studies can reveal details of diseases and injuries that no other imaging modality can match, which justifies the massive capital investments hospitals make to obtain them. But what if MRI scanners could be miniaturized? Is there something inherent in the technology that makes them so massive and so expensive that many institutions are priced out of the market? Or has technology advanced far enough that a truly portable MRI?

It turns out that yes, an inexpensive MRI scanner is not only possible, but can be made portable enough to wheel into a patient care room. It’s not without compromise, but such a device could make a huge impact on diagnostic medicine and extend MRI technologies into places far beyond the traditional hospital setting.

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The Vaccine Factory Inside You: RNA Vaccine Basics

May 4, 2020 by Dan Maloney 19 Comments

As the world pulls back from the acute phase of the COVID-19 pandemic, it enters what will be perhaps a more challenging time: managing the long-term presence of the SARS-CoV-2 virus that causes the disease. In the roughly two-century history of modern vaccination practices, we’ve gotten pretty good at finding ways to protect ourselves from infectious diseases, and there’s little doubt that we’ll do the same for SARS-CoV-2. But developing a vaccine against any virus or bacterium takes time, and in a pandemic situation, time is exactly what’s at a premium.

In an effort to create an effective vaccine against this latest viral threat, scientists and physicians around the world have been taking a different approach to inoculation. Rather than stimulating the immune system in the usual way with a weakened sample of the virus, they’re trying to use the genetic material of the virus to stimulate an immune response. These RNA vaccines are a novel approach to a novel infection, and understanding how they work will be key to deciding whether they’ll be the right way to attack this pandemic.

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FDA Approves Ventilator Designed By NASA’s Jet Propulsion Laboratory

May 1, 2020 by Mike Szczys 28 Comments

Yesterday NASA’s Jet Propulsion Laboratory announced that their ventilator design has received Emergency Use Authorization from the US Food and Drug Administration. This paves the way for the design to be manufactured for use in the treatment of COVID-19 patients.

JPL, which is tightly partnered with the California Institute of Technology, designed the ventilator for rapid manufacturing to meet the current need for respiratory tools made scarce by the pandemic. The design process took only 37 days and was submitted for FDA approval around April 23rd. They call it VITAL — Ventilator Intervention Technology Accessible Locally — a nod to NASA’s proclivity for acronyms.

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Maker Therapy Joins The Fight Against COVID-19

April 21, 2020 by Orlando Hoilett No comments

We love talking about makerspaces here at Hackaday. We love hearing about the camaraderie, the hacks, the outreach, the innovation, everything. Even more, we love seeing all the varying forms that makerspaces take, either in the hacks they create, the communities they reach out to, and especially their unique environments.

Recently, we came across Maker Therapy, a makerspace right inside a children’s hospital. Now, we’ve heard about hospital makerspaces here on Hackaday before, but what makes Maker Therapy particularly unique is it’s the first hospital makerspace that gives patients the opportunity to innovate right in the pediatric setting.

Inspired by patients and founded by Dr. Gokul Krishnan, Maker Therapy has been around for a few years now but recently popped up on our radar due to their unique position on the frontlines of the COVID-19 pandemic. As a makerspace located right inside a hospital, Maker Therapy is in the unique position to be the hospital’s very own rapid prototyping unit. Using 3D printing and other tools, Maker Therapy is able to make face shields and other important PPE right where they are needed the most.

Here at Hackaday, we salute and give our eternal gratitude to all the health care professionals fighting for our communities. Maybe some of your hacks and other designs could be used by initiatives like Maker Therapy? Until then, stay home and stay safe Hackaday. The only way we’ll get through this is together.