Saving 4 Patients With Just 1 Ventilator

March 19, 2020 by 59 Comments

We all know that COVID-19 is stressing our health system to the limit. One of the most important machines in this battle is the ventilator. Vents are critical for patients experiencing the worst symptoms of respiratory distress from the virus. Most of the numbers predict that hospitals won’t have enough ventilators to keep up with the needs during the height of the pandemic.

Now anyone with a walkman or iPod can tell you what they do when there is one music device and two people who want to listen: Plug in a Y-connector. Wouldn’t it be great if you could do the same thing with a medical ventilator? It turns out you can – – with some important caveats.

Way back in 2006, [Greg Neyman, MD and Charlene Babcock, MD] connected four simulated patients to a single ventilator. Ventilators connect to a patient with two tubes – an inflow and an exhaust. Using common parts available in just about any hospital, the doctors installed “T-tube” splitters on the inflow and exhaust tubes. They tested this with lung simulators and found that the system worked.

There were some important considerations though. The patients must be medically paralyzed, and have similar lung capacity — you couldn’t mix an adult and a child. The tubing length for each patient needs to be the same as well. The suggestion is to place the patients in a star pattern with the ventilator at the center of the star.

[Dr. Charlene Babcock] explains the whole setup in the video after the break.

Interestingly enough, this technique went from feasibility study to reality during the Las Vegas shooting a few years ago. There were more patients than ventilators, so emergency room doctors employed the technique to keep patients alive while equipment was brought in from outside hospitals. It worked — saving lives on that dark day.

The video and technique remind us of Apollo 13 and the CO2 scrubber modifications. Whatever it takes to keep people alive. We’ve already started looking into open source ventilators, but it’s good to see that medical professionals have been working on this problem for years.

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Sweet Streams Are Made Of These: Creating Music On The Command Line

March 19, 2020 by 3 Comments

There are countless ways to create music. In the simplest form, it won’t even require any equipment, as evidenced by beatboxing or a capella. If we move to the computer, it’s pretty much the same situation: audio programming languages have been around for as long as general-purpose high-level languages, and sound synthesis software along with them. And just as with physical equipment, none of that is particularly necessary thanks to sed. Yes, the sed, the good old stream editor, as [laserbat] shows in her music generating script.

Providing both a minified and fully commented version of Bach’s Prelude 1 in C major as example, [laserbat] uses a string representation of the sheet music as the script’s starting point, along with a look-up table of each transformed note’s wavelength. From here, she generates fixed length PCM square wave signals of each of the notes, to be piped as-is to the sound card via ALSA’s aplay or SoX’s play. To keep things simple enough, she stays within the region of printable characters here, using space and tilde as low and high values respectively, providing highest possible volume at the same time this way.

The concept itself is of course nothing new, it’s how .au and .wav files work, as well as these little C lines. And while the fixed note duration takes away some of the smoothness in [laserbat]’s version, adding variable duration might just be a hint too much for a sed implementation, although we’ve certainly seen some more complex scripts in the past.

[via r/programming]

Seven-Segment Shelves Do Double Duty

March 18, 2020 by 13 Comments

[Lewis] of [DIY Machines] was always on the lookout for that perfect something to hang above the couch. After spending a lot of time fruitlessly searching, he designed and built this awesome shelving unit with recessed lighting that doubles as a huge 7-segment clock.

The clock part works as you probably expect — an Elegoo Nano fetches the time from a real-time clock module and displays it on the WS2812B LED strips arranged in 7-segment formations. There’s a photocell module to detect the ambient light level in the room, so the display is never brighter than it needs to be.

Don’t have a 3D printer yet? Then you may need to pass on this one. Aside from the wood back plane and the electronics, the rest of this build is done with printed plastic, starting with 31 carefully-designed supports for the shelves. There are also the LED strip holders, and the sleeve pieces that hide all the wires and give this project its beautifully finished look.

You may have noticed that the far left digit isn’t a full seven segments. If you’re committed to 24-hour time, you’d have to adjust everything to allow for that, but you’d end up with two more shelves. Given the fantastic build video after the break, it probably wouldn’t take too long to figure all that out.

We like big clocks and we cannot lie. If you have room for it, build something like this blinkenlit beauty.

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GitHub On The Go

March 18, 2020 by 4 Comments

It is hard to find anyone that does any kind of software development that doesn’t have some interaction with GitHub. Even if you don’t host your own projects there, there are so many things to study and borrow on the site, that it is nearly ubiquitous. However, when you’ve needed GitHub on the run, you’ve probably had to turn to your phone browser and had a reduced experience. GitHub for Mobile is now out of beta and promises a more fluid phone-based GitHub experience.

In addition to working with tasks and issues, you can also review and merge pull requests. The app sends your phone notifications, too, which can be handy. As you might expect, you can get the app for Android or iPhone in the respective stores.

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Homemade Masks In A Time Of Shortage

March 18, 2020 by 528 Comments

Due to the worldwide pandemic of COVID-19, there has been a huge shortage of N95 masks. [Paddy Robertson] from Smart Air has been working on designs for a DIY mask that may be able to protect those who haven’t been able to secure their own masks. While there may be an abundance of memes around the various material people have been able to use to substitute for the filters, there is some very real science behind the sorts of materials that can effectively protect us from the virus.

According to a studied performed at Cambridge University during the 2009 H1N1 flu pandemic, while surgical masks perform the best at capturing Bacillus atrophaeus bacteria (0.93-1.25 microns) and Bacteriophage MS virus (0.023 microns), vacuum cleaner bags, and tea towels, and cotton T-shirts were not too far behind. The coronavirus is 0.1-0.2 microns, well within the range for the results of the tests.

As it turns out, cotton homemade masks may be quite effective as alternatives – not to mention reusable. They also found out that double layering the masks didn’t help with improving the protection against viruses. On the other hand, one significant design choice was the breathability of the material. While vacuum cleaner bags may be quite effective at keeping out small particles, they aren’t as comfortable or easy to breathe in as cotton masks.

Have you tried making your own cotton masks? In a time when hospitals are running low on surgical masks, it’s possibly the best option for helping to keep much-needed medical supplies in the hands of those helping at the front line.

[Thanks to pie for the tip!]

You’ll Flip For This Toggle Switch Handheld Game

March 18, 2020 by 13 Comments

Teacher says that every time a toggle switch clunks, a hacker gets their wings. Or something like that. All we know is that there are few things the hardware tinkerer likes more than the satisfying action of a nice flip. Which by extension means this handheld game built by [Roman Revzin] and controlled by nothing more than three toggle switches will likely be a big hit at the hackerspace.

The parts list for this game, which [Roman] calls the ToggleBoss, is about as short as it gets. There’s a NodeMCU ESP8266 development board, a common SH1106 OLED display, and a trio of suitably clunky toggle switches. Add a bit of wire, toss it all into a 3D printed enclosure, and you’re halfway to thumb flicking nirvana.

Naturally, you might be wondering about the sort of games that can be played with three latching digital inputs; after all, it’s not exactly the most conventional controller layout. But there is where ToggleBoss really shines. Instead of trying to shoehorn traditional games into an exceptionally unconventional system, [Roman] has come up with several games which really embrace the limited input offered to the user.

In a platforming game not unlike the classic Mario Bros, the positions of the physical switches are mapped to virtual walls that are raised and lowered to control a character’s movement through the level. Another game shows the player three dots which correspond to the intended switch states, which they have to match as quickly and as accurately as possible. [Roman] has released the source code to his current lineup of games, which hopefully will inspire others to try their hand at creating software for this fascinating little system.

With the availability of cheap OLED displays and powerful microcontrollers, we’ve started to see more of these bespoke gaming systems. While some will undoubtedly prefer a pocket full of Nintendo’s classics, we think there’s something special about a game system that you can truly call your own.

AvoRipe Takes A Firm Grip On The Ultimate First World Food Problem

March 18, 2020 by 14 Comments

You don’t have to be an extinct mammal or a Millennial to enjoy the smooth, buttery taste of an avocado. Being psychic on the other hand is definitely an advantage to catch that small, perfect window between raw and rotten of this divaesque fruit. But don’t worry, as modern problems require modern solutions, [Eden Bar-Tov] and [Elad Goldberg] built the AvoRipe, a device to notify you when your next avocado has reached that window.

Taking both the firmness and color of an avocado as indicators of its ripeness into account, the team built a dome holding a TCS3200 color sensor as stand for the avocado itself, and 3D printed a servo-controlled gripper with a force sensor attached to it. Closing the gripper’s arms step by step and reading the force sensor’s value will determine the softness the avocado has reached. Using an ESP8266 as centerpiece, the AvoRipe is turned into a full-blown IoT device, reporting the sensor readings to a smartphone app, and collecting the avocado’s data history on an Adafruit.IO dashboard.

There is unfortunately one big drawback: to calibrate the sensors, a set of nicely, ripe avocados are required, turning the device into somewhat of a chicken and egg situation. Nevertheless, it’s a nice showcase of tying together different platforms available for widescale hobbyist projects. Sure, it doesn’t hurt to know how to do each part from scratch on your own, but on the other hand, why not use the shortcuts that are at our disposal to remove some obstacles — which sometimes might include programming itself.

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