Condom And Catheter Team Up To Save New Mothers’ Lives

August 6, 2017 by 43 Comments

The title is sure to draw a snicker from some readers, but the purpose of this field-expedient treatment for postpartum hemorrhage is deadly serious, and a true medical hack that has the potential to save the lives of new mothers.

Postpartum hemorrhage is the leading cause of death during pregnancy, claiming about 86,000 women every year. While it can occur up to six weeks after giving birth, PPH is most serious immediately after delivery and can require aggressive treatment to prevent hypovolemic shock and eventual death. A fully equipped obstetrical suite will have access to an array of medications and devices to staunch the flow, including a uterine balloon tamponade (UBT) kit. But at $400 a kit, these devices are hard to come by in the developing world.

Not to be dissuaded, midwife [Anne Mulinge] from Nairobi, Kenya created a simple, cheap substitute using common items. A common urinary catheter is covered with an ordinary condom, the end of which is secured around the catheter with twine. Once inserted into the woman’s uterus, the condom is filled with saline solution through the catheter, expanding the condom and applying direct pressure to the bleeding uterine walls. The pressure allows the mother’s clotting mechanism to catch up with the decreased blood flow.

So far, [Anne] claims the device has saved three new mothers, and other midwives are being trained in the technique. Here’s hoping that more lives are saved with this simple hack, and perhaps with this more complex one designed to get blood to remote clinics as fast as possible.

Thanks to [LP Bing] for the tip.

A New Battery For A Potted Clock Module

August 6, 2017 by 31 Comments

If you did much dismantling of PCs back in the 1980s and 1990s, you might be familiar with the Dallas Semiconductor range of potted real-time clock modules. These were chunky dual-in-line devices containing clock and non-volatile RAM chips, a crystal, and a lithium battery. The battery was good for about a decade, which was fine for most PCs of the day because the majority of desktop computers are replaced long before that deadline.

[Glitch], however has an industrial single-board computer with a 486 processor that has had a life much more prolonged than its desktop siblings due to its application. The battery in the onboard Dallas DS1387 has long ago expired, and since these devices are so long out of production to be unavailable, he’s had to improvise.

Improving on some previous documented projects he found through an internet search, he carefully ground away the potting compound to reveal a couple of the battery conductors, cut them with a PCB drill, and mounted a lithium cell holder on the top of the device with some tidily soldered Kynar wires to bring in the power. A CR1225 cell was used rather than the ubiquitous CR2032, as space was at a premium in the width of the ISA card form factor.

The potted RTC module is something of a rare device these days, but if you have a retro computer containing one this seems to be a very useful piece of work to bring it back to life. We’ve covered another similar one with a slightly larger battery in the past.

Ink-Filled Machine Badges Score Respect For Your Gear

August 5, 2017 by 26 Comments

Remember the good old days when machines had a stout metal badge instead of cheap vinyl decals, and nameplates on motors were engraved in metal rather than printed on a label with a QR code? Neither do we, but these raised brass labels with color filled backgrounds look great, they’re surprisingly easy to make, and just the thing your gear needs to demand respect as a cherished piece of gear.

The ‘easy’ part of this only comes if you have access to a machine shop like [John] at NYC CNC does. To be fair, the only key machine for making these plates is a laser cutter, and even a guy like [John] needed to farm that out. The process is very straightforward — a brass plate is cleaned and coated with lacquer, which is then removed by the laser in the areas that are to be etched. The plate is dipped in an electrolyte solution for etching, cleaned, and powder coated. After curing the powder coat with a heat gun rather than an oven — a tip worth the price of admission by itself — the paint is sanded off the raised areas, the metal is polished, and a clear coat applied to protect the badge.

Plates like these would look great for a little retro-flair on a new build like this Nixie power meter, or allow you to restore a vintage machine like this classic forge blower.

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Maintain Temperature With A DIY Laboratory Dry Bath

August 5, 2017 by 2 Comments

[abizar] lucked into some aluminum blocks, one of which had test-tube-sized holes in it–just the thing to turn into a dry bath for his biology projects.

He stuck a 100W positive temperature coefficient heater into the bottom of the block using silicone glue, and the heater heated the block up in around half an hour. He connected a temperature controller to maintain the temperature at an ambient 95C, with a controller monitoring a thermistor to keep the block within the pre-determined range. The heater has an auto shutoff if it got too hot, so [abizar] felt safe keeping the dry bath on, unmonitored.

The aluminum block sits in a plywood box lined with rubber from an inner tube, with the heater underneath the block and the temperature controller underneath that, separated by more plywood from the heat. The result? A dry, temperature regulated bath for 20 1.5ml test tubes.

Looking to tool up? Check out the plethora of biohacking tools on Hackaday, including a DIY CO2 incubator, a basic biohacker’s toolkit, and a cheap electrophoresis rig.

Dedicated Button For Toggling Screens

August 5, 2017 by 25 Comments

Anyone who regularly presents to an audience these days has known the pain of getting one’s laptop to work reliably with projection hardware. It’s all the more fraught with pain when you’re hopping around from venue to venue, trying desperately to get everything functioning on a tight schedule. [Seb] found that the magic keystrokes they used to deal with these issues no longer worked on the Macbook Pro Touchbar, and so a workaround was constructed in hardware.

The build itself is simple – an Adafruit Trinket serves as the brains, with a meaty 12mm tactile button used for input. The Trinket emulates a USB keyboard and sends the Cmd-F1 keypress to the computer when the button is pressed. The button’s even mounted in a tidy deadbugged fashion.

While it’s not at all complicated from a build standpoint, the key to this project is that it’s a great example of using the tools available to solve real-life problems. When you’re in a rush with 300 people waiting for your talk to start, the last thing you need to be worrying about is a configuration issue. [Seb] now has a big red button to mash to get out of trouble and get on with the job at hand. It does recall this much earlier hack for emulating a USB keyboard with an Arduino Uno or Mega. It’s a useful skill to have!

 

Hackaday Prize Entry: Low Cost KVM

August 5, 2017 by 30 Comments

Back in the old days, when handing someone a DB serial cable when they asked for a DE serial cable would get you killed, KVM switchers were a thing. These devices were simple boxes with a few VGA ports, a few PS/2 ports, and a button or dial that allowed your input (keyboard and mouse) and output (video) to be used with multiple computers. Early KVMs were really just a big ‘ol rotary switch with far, far too many poles. Do you remember that PS/2 wasn’t able to be hot plugged? The designers of these KVMs never knew that.

Today, KVM switchers are a bit more complicated than a simple rotary switch. We’re not dealing with VGA anymore — we have HDMI muxes. We’re also not dealing with PS/2 anymore, and USB requires a bit of microelectronics to switch from one computer to another. For one of his many Hackaday Prize entries, [KC Lee] is designing a low-cost HDMI switch and USB mux. It works, it’s cheap, and if you need to switch a keyboard, mouse, and monitor between boxes, it’s exactly what you need.

First off, the HDMI switching. Designing a switch for HDMI would usually take some obscure parts, intricate routing, and a lot of prototyping time. [KC] found a way around this: just hack up a $5 HDMI switch. This cheap HDMI switch is as simple as it gets, with an HDMI mux doing the heavy lifting and an 8-pin microcontroller to handle the buttons and a selector LED.

For the USB, there are a few more design choices. For USB 1.x switching, [KC] figures he can get away with a 74HC4052 dual 4:1 analog mux. Yes, he’s doing digital with analog chips, the heathen. There are drawbacks to this: everything could break, and it’s only USB 1.x, anyway. For a USB 2.0 KVM, there are a few more professional options. The OnSemi NCN9252 is a proper USB 2.0 mux, and in the current design.

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