Open-Source Medical Devices Hack Chat

January 28, 2020 by 5 Comments

Join us on Wednesday, January 29 at noon Pacific for the Open-Source Medical Devices Hack Chat with Tarek Loubani!

In most of the developed world, when people go to see a doctor, they’re used to seeing the latest instruments and devices used. Most exam rooms have fancy blood pressure cuffs, trays of shiny stainless steel instruments, and a comfortable exam table covered by a fresh piece of crisp, white paper. Exams and procedures are conducted in clean, quiet places, with results recorded on a dedicated PC or tablet.

Such genteel medical experiences are far from universal, though. Many clinics around the world are located in whatever building is available, if they’re indoors at all. Supplies may be in chronically short supply, and to the extent that the practitioners have the instruments they need to care for patients, they’ll likely be older, lower-quality versions.

Tarek Loubani is well-versed in the practice of medicine under conditions like these, as well as far worse situations. As an emergency physician and researcher in Canada, he’s accustomed to well-appointed facilities and ample supplies. But he’s also involved in humanitarian relief, taking his medical skills and limited supplies to places like Gaza. He has seen first-hand how lack of the correct tools can lead to poor outcomes for patients, and chose to fight back by designing a range of medical devices and instruments that can be 3D-printed. His Glia Project has free plans for a high-quality stethoscope that can be built for a couple of dollars, otoscopes and pulse oximeters, and a range of surgical tooling to make the practice of medicine under austere conditions a little easier. Continue reading “Open-Source Medical Devices Hack Chat” →

Clock Uses Custom LED Displays To Keep Myst Time

January 28, 2020 by 17 Comments

The Myst fans in the audience will love this project because it displays the 25-hour timekeeping system of the D’ni. The hardware hackers will lean a little closer to their screen because it does so with custom made 25-segment LEDs, and the precision obsessed will start breathing heavily when they hear it maintains an accuracy of 0.001 seconds. As for which of those camps creator [Mike Ando] most identifies with, we can’t say. But we definitely respect his style.

We’ll spare you the in-depth description of the base-25 number system apparently used in the Myst franchise. If you’re interested enough you can click on through to the project’s Hackaday.io page and learn how to actually read the clock. Presumably you’ll then come back here and leave your comment in Klingon.

Let’s instead jump right to the part that really gets us excited, those custom displays. To create them, [Mike] cut the face out of black acrylic with a laser, and filled each void with a mixture of clear resin and very fine gypsum plaster. Getting the mix right can be a little finicky as the plaster can clump up, but the end result diffuses the light nicely. The acrylic front panel and a couple of cardboard “gaskets” to keep the light from leaking onto adjacent segments is then stacked on top of a PCB with corresponding 0603 SMD LEDs.

Beyond the soul-crushing number of wires required to hook everything up internally, the rest of the project is relatively straightforward. It uses a WeMos D1 Mini to connect to the WiFi network and pull the current time down from the geographically closest NTP server every couple of hours. Rather than putting a temperature controlled oscillator on the board, [Mike] has decided to pin his accuracy on a constantly on Internet connection and aggressive synchronizations.

From impressive curved bar graph modules to displays segmented with household items, we’ve seen our fair share of custom indicators. But we have to admit that building 25-segment LED displays for the alphabet of a fictional interstellar species sets the bar pretty high.

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Lead-Free Solder Alloys: Their Properties And Best Types For Daily Use

January 28, 2020 by 99 Comments

Lead-free solder alloys have been around for as long as people have done soldering, with sources dating back about 5,000 years. Most of these alloys were combinations like copper-silver or silver-gold and used with so-called hard soldering. That’s a technique still used today to join precious and semi-precious metals together. A much more recent development is that of soldering electronic components together, using ‘soft soldering’, which entails much lower temperatures.

Early soft soldering used pure tin (Sn), yet gradually alloys were sought that would fix issues like thermal cycling, shock resistance, electron migration, and the development of whiskers in tin-based alloys. While lead (Pb) managed to fill this role for most soldering applications, the phasing out of lead from products, as well as new requirements for increasingly more fine-pitched components have required the development of new solder alloys that can fill this role.

In this article we’ll be looking at the commonly used lead-free solder types for both hobby and industrial use, and the dopants that are used to improve their properties.

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Raspberry Pi 4 Benchmarks: 32- Vs 64-bits

January 28, 2020 by 58 Comments

[Matteo] bought a new Raspberry Pi 4. Why not? You get a quad-core ARM processor, up to 4 GB of RAM, and a gigabit Ethernet port for $35 $35-55. However, the default operating system is still a 32-bit system and doesn’t take advantage of the Pi 4’s 64-bit capable CPU. So he installed a light version of 64-bit Debian and ran some benchmarks for the Raspberry Pi 4 running both 32-bit and 64-bit operating systems.

It really shouldn’t be surprising that the 64-bit OS did better in nearly every test. If anything is surprising, it may be that the difference is so pronounced. Some of the benchmarks, like Dhrystones, probably don’t relate much to real-life usage. But some things, like computing a hash, is something you probably do pretty often in normal usage, and the timing difference is pronounced.

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New Part Day: SK6812 Mini-E. A Hand Solderable Neopixel Compatible LED!

January 28, 2020 by 23 Comments

Normally when we give you a New Part Day piece, it concerns a component that you will have never seen before. The subject of this find by [Robert Fitzsimons] then is a slight departure from that norm, given that the SK6812 Mini-E is a WS2812 or Neopixel compatible multi-colour LED of a type that has been available for a while now.

What makes this component new though is its packaging. The Mini-E variant of the SK6812 only appeared last year and has now found its way through to smaller order quantities on AliExpress. Its special feature is that it has a set of flat leads rather than the usual pads on the underside of the package. This means that unlike its predecessors it is readily hand solderable, as he demonstrates by attaching a set of leads to one.

The leads emerge halfway up the side of the device, which seems designed to be mounted recessed within a PCB hole. He demonstrates this with a piece of stripboard, and remarks that they would make a good choice for many small projects such as Shitty Add-On boards.

We’ve touched the leadless SK6812s a few times before, along the way remarking that in some respects they are better than the WS2812 they follow.

Continue reading “New Part Day: SK6812 Mini-E. A Hand Solderable Neopixel Compatible LED!” →

A Miniature Laptop You Can Build Yourself

January 27, 2020 by 15 Comments

Over the last couple of years, we’ve seen more and more hackers building their own custom computers. We’re not just talking casemods here; enabled by advancements in desktop 3D printing and increasingly powerful boards such as the Raspberry Pi 4, these are machines designed and built from the ground up to meet the creator’s particular set of needs and desires.

A perfect example of this trend is the Rasptop 2.0, a remarkably practical design for a 3D printed miniature laptop. Despite the name, you don’t even need to use the Raspberry Pi if you don’t want to. Creator [Morgan Lowe] has designed the Rasptop to take other single board computers (SBCs) such as the Asus Tinker Board or even the Intel Atom powered Up Board. So whether you want an energy efficient ARM machine running Linux for development, or a mobile Windows box for on the go gaming, you can use the same printed parts.

At the most basic level, the Rasptop 2.0 is just a hollow box with a hinged compartment for a screen mounted on top. You’re free to equip it with whatever hardware you chose. If you’re after maximum runtime you could fill all the free space with batteries, or maybe install multiple hard drives if you’re a data horder in need of a mobile terminal. Even the various SBCs that [Morgan] has tested are really just suggestions. The choice is yours.

Perhaps also our favorite feature of the Rasptop is how he worked a keyboard into the design. Rather than just leaving a big rectangle in the STL for you to shove a mobile keyboard into, the top surface is designed to mount the PCB and membrane keypad of one of those mini wireless keyboards you see on all the import sites. Aside from the fact it’s a good deal chunkier than what we expect from modern mobile devices, it has a very finished and professional overall look.

Of course if you’d rather use all these powerful tools to build a computer that’s somewhat farther off the beaten track, your design could abandon the traditional computer form factors altogether.

The Options For Low Cost ROV Tethers

January 27, 2020 by 22 Comments

Wireless connections are cool and all, but sometimes you just need a bit of copper. This interesting article on SV Seeker discusses the various ways of making a tether for a remotely operated vehicle (ROV). They experimented with a number of different cables, including gel-filled Cat 5 designed for burial and wrapping the cable in polypropylene rope to keep it protected and buoyant. They also looked at using a single core solid coax cable with an Ethernet to coax converter on either end wrapped in stretch webbing. The upside of using coax would be the length: it can handle over a mile of cable, which should be more than enough for this project. The downside is that they found that the coax stretches under strain, messing with the signal.

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