The Mark 14 Torpedo — When Just About Everything Goes Wrong, Even The Testing

May 13, 2020 by 70 Comments

I am a fan of the saying that those who don’t know history are doomed to repeat it. After all, humans have been building things for a number of centuries and we should learn from the engineers of the past. While you can learn a lot studying successes, sometimes — maybe even most of the time — we learn more from studying failure. The US Navy’s Mark 14 torpedo certainly has a lot to teach us.

The start of the story was the WWI-era Mark 10 torpedo which was fine for its day, but with faster destroyers and some additional data about how to best sink enemy ships it seemed necessary to build a new torpedo that would be faster, carry more explosive charge, and use a new method of detonation. Work started in 1931 with a $143,000 budget which may sound laughable today, but that was a lot of coin in the 1930s. Adjusted for inflation, that’s about $2.5 million.

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Printed Jig Is A Welding Rig

May 13, 2020 by 17 Comments

[NixieGuy] was scheming to build robots with cable-driven joints when the pandemic hit. Now that component sourcing is scarce, he’s had to get creative when it comes to continuous cables. These cables need to be as seamless as possible to avoid getting caught on the pulleys, so [Nixie] came up with a way to weld together something he already has on hand — lengths of .45mm steel cable.

The 3D printed jig is designed to be used under a digital microscope, and even clamps to the pillar with screws. Another set of screws holds the two wires in place while they are butt welded between two pieces of copper.

[Nixie] adds a spot of solder paste for good measure, and then joins the wires by attaching his bench power supply set to 20V @ 3.5A to the copper electrodes. We love that [Nixie] took the time to streamline the jig design, because it looks great.

This just goes to show you that great things can happen with limited resources and a little bit of imagination. [Nixie] not only solved his own supply chain problem, he perfected a skill at the same time. If you don’t have a bench supply, you might be able to get away with a battery-powered spot welder, depending on your application.

A Redox Flow Battery Made From Iron Industry Waste

May 13, 2020 by 54 Comments

Researchers at the University of Southern California have found a way to make an effective and competitive redox flow battery out of the iron industry’s waste products.  Luckily for us, the results of the paper were posted on an open journal and we could take a look into the tech behind this battery.

As electric utilization, adoption of electric cars, and the use of renewable power continues to rise, engineers all over are searching for the perfect utility scale battery. We have all heard about Tesla’s 100MW lithium battery pack in South Australia. The system is a massive success and has already paid itself back. However, engineers all over were quick to point out that, until we have a breakthrough, Lithium cells are just not the right choice for a utility system in the long run. There has to be a better solution. Continue reading “A Redox Flow Battery Made From Iron Industry Waste” →

Floppy Drive Keyboard Is Inefficient Fun

May 13, 2020 by 39 Comments

Most of us are used to a typical 101-key setup for typing on our machines. Mobile and touchscreen devices have offered alternative interfaces over the years, but generally still sticking to QWERTY or other similar layouts. [foone] cares not for convention however, building a text-entry device based on the iconic floppy disk.

The build starts with a standard PC floppy drive, hooked up to an interface board to allow it to work over USB. It’s hooked up to a Raspberry Pi, which runs a Python program that listens out for media insertion events. When a new disk is detected, it reads the volume label, and sends it over to a Teensy LC which simulates a USB keyboard attached to the host PC. The setup uses 29 disks, for A-Z, !, shift, and space. It’s all stuffed inside a SCSI disk enclosure which helpfully provides a power supply along with the classic beige 90s aesthetic.

While you’re probably not going to be typing out your dissertation on this thing, it makes for an excellent conversation piece. We’ve featured some of [foone]’s eclectic work before, too. Video after the break.

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The DOOM Chip

May 13, 2020 by 18 Comments

It’s a trope among thriller writers; the three-word apocalyptic title. An innocuous item with the power to release unimaginable disaster, which of course our plucky hero must secure to save the day. Happily [Sylvain Lefebvre]’s DOOM chip will not cause the world to end, but it does present a vision of a very 1990s apocalypse. It’s a hardware-only implementation of the first level from id Software’s iconic 1993 first-person-shooter, DOOM. As he puts it: “Algorithm is burned into wires, LUTs and flip-flops on an #FPGA: no CPU, no opcodes, no instruction counter. Running on Altera CycloneV + SDRAM”. It’s the game, or at least the E1M1 map from it sans monsters, solely in silicon. In a very on-theme touch, the rendering engine has 666 lines of code, and the level data is transcribed from the original into hardware tables by a LUA script. It doesn’t appear to be in his GitHub account so far, but we live in hope that one day he’ll put it up.

“Will it run DOOM” is almost a standard for new hardware, but it conceals the immense legacy of this game. It wasn’t the first to adopt a 1st-person 3D gaming environment, but it was the game that defined the genre of realistic and immersive FPS releases that continue to this day. We first played DOOM on a creaking 386, we’ve seen it on all kinds of hardware since, and like very few other games of its age it’s still receiving active development from a large community today. We still mourn slightly that it’s taken the best part of three decades for someone to do a decent Amiga port.

Foamboard Makes For A Light Hovercraft

May 12, 2020 by 3 Comments

If we are to believe many science fiction movies, one day throngs of people wearing skin-tight silver spandex jumpsuits will be riding around on hovercraft. Hovercraft haven’t really taken the world by storm, but [Fitim-Halimi] built his own model version and shows you how he did it. You can see the little craft moving in the video below.

In theory, a hovercraft is pretty simple, but in practice they are not as easy as they look. For one thing, you need a lot of air to fill the plenum chamber to get lift. That’s usually a noisy operation. The solution? In this case, a hairdryer gave up its motor for the cause. In addition, once floating on a near-frictionless cushion of air, you have to actually move without contacting the ground. Like many real hovercraft, this design uses another fan to push it along. You can see in the video that the designer uses Jedi hand motions to control the vehicle.

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A Smart Bandage For Monitoring Chronic Wounds

May 12, 2020 by 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.