Retrotechtacular: The Deadly Shipmate

November 27, 2024 by Dan Maloney 33 Comments

During World War II, shipboard life in the United States Navy was a gamble. No matter which theater of operations you found yourself in, the enemy was all around on land, sea, and air, ready to deliver a fatal blow and send your ship to the bottom. Fast forward a couple of decades and Navy life was just as hazardous but in a different way, as this Navy training film on the shipboard hazards of low-voltage electricity makes amply clear.

With the suitably scary title “115 Volts: A Deadly Shipmate,” the 1960 film details the many and various ways sailors could meet an untimely end, most of which seemed to circle back to attempts to make shipboard life a little more tolerable. The film centers not on the risks of a ship’s high-voltage installations, but rather the more familiar AC sockets used for appliances and lighting around most ships. The “familiarity breeds contempt” argument rings a touch hollow; given that most of these sailors appear to be in their 20s and 30s and rural electrification in the US was still only partially complete through the 1970s, chances are good that at least some of these sailors came from farms that still used kerosene lamps. But the point stands that plugging an unauthorized appliance into an outlet on a metal ship in a saltwater environment is a recipe for being the subject of a telegram back home.

The film shows just how dangerous mains voltage can be through a series of vignettes, many of which seem contrived but which were probably all too real to sailors in 1960. Many of the scenarios are service-specific, but a few bear keeping in mind around the house. Of particular note is drilling through a bulkhead and into a conduit; we’ve come perilously close to meeting the same end as the hapless Electrician’s Mate in the film doing much the same thing at home. As for up-cycling a discarded electric fan, all we can say is even brand new, that thing looks remarkably deadly.

The fact that they kept killing the same fellow over and over for each of these demonstrations doesn’t detract much from the central message: follow orders and you’ll probably stay alive. In an environment like that, it’s probably not bad advice.

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Electric Guitar Shocks You For Missing A Note

October 6, 2022 by Lewin Day 6 Comments

Rocksmith is a popular video game that works like Guitar Hero, but with a real guitar. You have to play well and hit the right notes, or the game penalizes your score. [Lightwing] took the stakes up a notch, though, adding a system that shocks the player every time they fail.

To achieve this, it was necessary to detect when the player missed a note. Initial attempts involved using Tensor Flow AI to detect the game state from the screen, but it was unreliable. Instead, the game’s memory was read to achieve detection. When the player misses a note, a certain section of memory changes, and a script reads the change in game state. It then sends a signal to an Arduino which triggers the stun gun’s fire button, which shocks the player holding the guitar.

As you might expect, the documentation for this project includes a video which involves plenty of gratuitous electric shocks when [Lightwing] makes mistakes. Fair warning — there’s plenty of colorful language when the stun gun fires. Generally, a powerful shock ends with screams a dropped guitar, and too much fear to continue.

It’s painful enough that it’s probably not a useful teaching tool for learning the guitar. We’ve seen similar shocking builds before, too, like this simple wire game.

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Neural Network Zaps You To Take Better Photographs

February 9, 2018 by Dan Maloney 38 Comments

It’s ridiculously easy to take a bad photograph. Your brain is a far better Photoshop than Photoshop, and the amount of editing it does on the scenes your eyes capture often results in marked and disappointing differences between what you saw and what you shot.

Taking your brain out of the photography loop is the goal of [Peter Buczkowski]’s “prosthetic photographer.” The idea is to use a neural network to constantly analyze a scene until maximal aesthetic value is achieved, at which point the user unconsciously takes the photograph.

But the human-computer interface is the interesting bit — the device uses a transcutaneous electrical nerve stimulator (TENS) wired to electrodes in the handgrip to involuntarily contract the user’s finger muscles and squeeze the trigger. (Editor’s Note: This project is about as sci-fi as it gets — the computer brain is pulling the strings of the meat puppet. Whoah.)

Meanwhile, back in reality, it’s not too strange a project. A Raspberry Pi watches the scene through a Pi Cam and uses a TensorFlow neural net trained against a set of high-quality photos to determine when to trip the shutter. The video below shows it in action, and [Peter]’s blog has some of the photos taken with it.

We’re not sure this is exactly the next “must have” camera accessory, and it probably won’t help with snapshots and selfies, but it’s an interesting take on the human-device interface. And if you’re thinking about the possibilities of a neural net inside your camera to prompt you when to take a picture, you might want to check out our primer on TensorFlow to get started.

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Condom And Catheter Team Up To Save New Mothers’ Lives

August 6, 2017 by Dan Maloney 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.

The Importance Of Electrical Safety

March 1, 2017 by Elliot Williams 78 Comments

Everything you do bears some risk of getting you hurt or killed. That’s just the way life is. Some people drown in the bath, and others get kilovolt AC across their heart. Knowing the dangers — how drastic and how likely the are — is the first step toward mitigating them. (We’re not saying that you shouldn’t bathe or play with high voltages.)

This third chapter of an e-book on electronics is a good read. It goes through the physiology of getting shocked (DC is more likely to freeze your muscles, but AC is more likely to fibrillate your heart) and the various scenarios that you should be looking out for. There’s a section on safe practices, and safe circuit design. It’s the basics, but it’s also stuff that we probably should have known when we started messing around with electrons in bulk.

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Extreme Wire Buzz Game

January 5, 2016 by James Hobson 12 Comments

Remember that old buzz wire game? Kinda like Operation, where you have to do a dexterous task without touching the walls… Well here’s a fun twist on it — what if you throw a 4 million volt stun gun into the mix?

That’s right, [Mike] was given a taser flashlight, and he had this brilliant idea to make a game out of it. The game features three metal wire sections which get progressively harder, with higher risk too! Using the handle, you have to guide an eye-bolt along the wire sections. But be careful — the circuit is live, and if you touch the metal, you’re going to get quite the shock!

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Shocking Operation Makes Sure You Have Skin In The Game

March 23, 2013 by Mike Szczys 4 Comments

operation-shocks-you

Odds are you played the game of Operation when you were a kid. The classic electronic toy challenges you to use a tethered tweezers to extract plastic pieces without touching the sides of the holes they’re hiding in. This upgrade makes the challenge more interesting for a grown-up audience. If you touch the sides you won’t hear a jarring sound, you’ll get a painful shock!

The modification starts by clipping off the melted plastic portions that hold the paperboard face plate on the game. From there the original electronics are completely removed. We think this a bit of a mistake as we’d still like spectators to hear the sound as the player gets a shock. But we digress. The circuit board from a disposable camera is patched into the game. A wrist band forms an electrical connection with your body, providing a path for the camera’s flash capacitor to discharge if you happen to touch the sides with the tweezers.

This write-up is missing one important thing: video of someone getting shocked. [Psycosisnine] promises to add some soon, but for now you’ll just have to fall back on our absolute favorite Mindflex shock project.