Bullet-proofing Your Car With An Affordable Composite Armor

Remember those actions movies like The Fast and the Furious where cars are constantly getting smashed by fast flying bullets? What would it have taken to protect the vehicles from AK-47s? In [PrepTech]’s three-part DIY composite vehicle armor tutorial, he shows how he was able to make his own bulletproof armor from scratch. Even if you think the whole complete-collapse-of-civilization thing is a little far-fetched, you’ve got to admit that’s pretty cool.

The first part deals with actually building the composite. He uses layers of stainless steel, ceramic mosaic tiles, and fiberglass, as well as epoxy resin in order to build the composite. The resin was chosen for its high three-dimensional cross-linked density, while the fiberglass happened to be the most affordable composite fabric. Given the nature of the tiny shards produced from cutting fiberglass, extreme care must be taken so that the shards don’t end up in your clothes or face afterwards. Wearing a respirator and gloves, as well as a protective outer layer, can help.

After laminating the fabric, it hardens to the point where individual strands become stiff. The next layer – the hard ceramic – works to deform and slow down projectiles, causing it to lose around 40% of its kinetic energy upon impact. He pipes silicone between the tiles to increase the flexibility. Rather than using one large tile, which can only stand one impact, [PrepTech] uses a mosaic of tiles, allowing multiple tiles to be hit without affecting the integrity of surrounding tiles. While industrial armor uses boron or silicon carbide, ceramic is significantly lower cost.

The stainless steel is sourced from a scrap junkyard and cut to fit the dimensions of the other tiles before being epoxied to the rest of the composite. The final result is allowed to sit for a week to allow the epoxy to fully harden before being subject to ballistics tests. The plate was penetrated by a survived shots from a Glock, Škorpion vz. 61, and AK-47, but was penetrated by the Dragunov sniper rifle. Increasing the depth of the stainless steel to at least a centimeter of ballistic grade steel may have helped protect the plate from higher calibers, but [PrepTech] explained that he wasn’t able to obtain the material in his country.

Nevertheless, the lower calibers were still unable to puncture even the steel, so unless you plan on testing out the plate on high caliber weapons, it’s certainly a success for low-cost defense tools.

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Tracking Wasted Time With A Ferrofluid Clock

We know this project is supposed to be about developing a fine-looking ferrofluid clock, and not about the value of procrastination. But after watching the video below, see if you don’t think that procrastination has taken these two students further than expected.

We first ran into [Simen] and [Amund] several months ago when they launched their ferrofluid project in a fit of “There’s got to be more to life than studying.” It seemed then that building a good-looking, functional ferrofluid display would be a temporary distraction, but the problems posed proved to be far deeper and thornier than either of the electrical engineering students expected. The idea is simple: contain a magnetic fluid between two transparent panels and create pixels using an array of electromagnets to move dots of the fluid around. The implementation, however, was another matter, with the ferrofluid itself proved to be the biggest obstacle. All the formulas they tried seemed to coagulate or degrade over time and tended to stain the glass. While the degradation was never fully sorted, they managed to work around the staining by careful cleaning of the glass and using a saturated brine solution to fill the container.

Backed by 252 electromagnets and drivers on ten custom PCBs, the video below shows the (mostly) finished panel in action as a clock. We’re impressed by the smoothness of the movements of each pixel, even if there’s a bit of drooping at the bottom thanks to gravity. As for the future of the project, that’s unclear since [Simen] is headed off for a NASA internship. We’re not sure if that was despite or because of this procrastination-driven project, but we congratulate him either way and look forward to hearing more from both of them in the future.

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Robot Vs. Superbug

Working in a university or research laboratory on interesting, complicated problems in the sciences has a romanticized, glorified position in our culture. While the end results are certainly worth celebrating, often the process of new scientific discovery is underwhelming, if not outright tedious. That’s especially true in biology and chemistry, where scaling up sample sizes isn’t easy without a lot of human labor. A research group from Reading University was able to modify a 3D printer to take some of that labor out of the equation, though.

This 3D printer was used essentially as a base, with the printing head removed and replaced with a Raspberry Pi camera. The printer X/Y axes move the camera around to all of the different sample stored in the print bed, which allows the computer attached to the printer to do most of the work that a normal human would have had to do. This allows them to scale up massively and cheaply, presumably with less tedious inputs from a large number of graduate students.

While the group hopes that this method will have wide applicability for any research group handling large samples, their specific area of interest involves researching “superbugs” or microbes which have developed antibiotic resistance. Their recently-published paper states that any field which involves bacterial motility, colony growth, microtitre plates or microfluidic devices could benefit from this 3D printer modification.

pierced puffed exposed leads lithium ion battery

Lessons In Li-Ion Safety

If you came here from an internet search because your battery just blew up and you don’t know how to put out the fire, then use a regular fire extinguisher if it’s plugged in to an outlet, or a fire extinguisher or water if it is not plugged in. Get out if there is a lot of smoke. For everyone else, keep reading.

I recently developed a product that used three 18650 cells. This battery pack had its own overvoltage, undervoltage, and overcurrent protection circuitry. On top of that my design incorporated a PTC fuse, and on top of that I had a current sensing circuit monitored by the microcontroller that controlled the board. When it comes to Li-Ion batteries, you don’t want to mess around. They pack a lot of energy, and if something goes wrong, they can experience thermal runaway, which is another word for blowing up and spreading fire and toxic gasses all over. So how do you take care of them, and what do you do when things go poorly?

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Azobenzene Stores Solar Energy

Probably the most efficient way to convert solar energy into electricity is the old fashioned way, heating water into steam and turning a turbine. This remains a messy affair though and you don’t really want a steam boiler on your roof, so solar cells are popular. However, there’s some new research showing how a molecule can absorb solar energy, store it, and then release the heat on demand years later. This could offer new ways to collect and even transport solar power. This new molecule, derived from azobenzene, holds immense promise to change the way we work with solar power.

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Hackaday Links: October 20, 2019

It’s Nobel season again, with announcements of the prizes in literature, economics, medicine, physics, and chemistry going to worthies the world over. The wording of the Nobel citations are usually a vast oversimplification of decades of research and end up being a scientific word salad. But this year’s chemistry Nobel citation couldn’t be simpler: “For the development of lithium-ion batteries”. John Goodenough, Stanley Whittingham, and Akira Yoshino share the prize for separate work stretching back to the oil embargo of the early 1970s, when Goodenough invented the first lithium cathode. Wittingham made the major discovery in 1980 that adding cobalt improved the lithium cathode immensely, and Yoshino turned both discoveries into the world’s first practical lithium-ion battery in 1985. Normally, Nobel-worthy achievements are somewhat esoteric and cover a broad area of discovery that few ordinary people can relate to, but this is one that most of us literally carry around every day.

What’s going on with Lulzbot? Nothing good, if the reports of mass layoffs and employee lawsuits are to be believed. Aleph Objects, the Colorado company that manufactures the Lulzbot 3D printer, announced that they would be closing down the business and selling off the remaining inventory of products by the end of October. There was a reported mass layoff on October 11, with 90 of its 113 employees getting a pink slip. One of the employees filed a class-action suit in federal court, alleging that Aleph failed to give 60 days notice of terminations, which a company with more than 100 employees is required to do under federal law. As for the reason for the closure, nobody in the company’s leadership is commenting aside from the usual “streamlining operations” talk. Could it be that the flood of cheap 3D printers from China has commoditized the market, making it too hard for any manufacturer to stand out on features? If so, we may see other printer makers go under too.

For all the reported hardships of life aboard the International Space Station – the problems with zero-gravity personal hygiene, the lack of privacy, and an aroma that ranges from machine-shop to sweaty gym sock – the reward must be those few moments when an astronaut gets to go into the cupola at night and watch the Earth slide by. They all snap pictures, of course, but surprisingly few of them are cataloged or cross-referenced to the position of the ISS. So there’s a huge backlog of beautiful but unknown cities around the planet that. Lost at Night aims to change that by enlisting the pattern-matching abilities of volunteers to compare problem images with known images of the night lights of cities around the world. If nothing else, it’s a good way to get a glimpse at what the astronauts get to see.

Which Pi is the best Pi when it comes to machine learning? That depends on a lot of things, and Evan at Edje Electronics has done some good work comparing the Pi 3 and Pi 4 in a machine vision application. The SSD-MobileNet model was compiled to run on TensorFlow, TF Lite, or the Coral USB accelerator, using both a Pi 3 and a Pi 4. Evan drove around with each rig as a dashcam, capturing typical street scenes and measuring the frame rate from each setup. It’s perhaps no surprise that the Pi 4 and Coral setup won the day, but the degree to which it won was unexpected. It blew everything else away with 34.4 fps; the other five setups ranged from 1.37 to 12.9 fps. Interesting results, and good to keep in mind for your next machine vision project.

Have you accounted for shrinkage? No, not that shrinkage – shrinkage in your 3D-printed parts. James Clough ran into shrinkage issues with a part that needed to match up to a PCB he made. It didn’t, and he shared a thorough analysis of the problem and its solution. While we haven’t run into this problem yet, we can see how it happened – pretty much everything, including PLA, shrinks as it cools. He simply scaled up the model slightly before printing, which is a good tip to keep in mind.

And finally, if you’ve ever tried to break a bundle of spaghetti in half before dropping it in boiling water, you likely know the heartbreak of multiple breakage – many of the strands will fracture into three or more pieces, with the shorter bits shooting away like so much kitchen shrapnel. Because the world apparently has no big problems left to solve, a group of scientists has now figured out how to break spaghetti into only two pieces. Oh sure, they mask it in paper with the lofty title “Controlling fracture cascades through twisting and quenching”, but what it boils down to is applying an axial twist to the spaghetti before bending. That reduces the amount of bending needed to break the pasta, which reduces the shock that propagates along the strand and causes multiple breaks. They even built a machine to do just that, but since it only breaks a strand at a time, clearly there’s room for improvement. So get hacking!

Alternative Photography Hack Chat

Join us on Wednesday, October 2 at noon Pacific for the Alternative Photography Hack Chat with Pierre-Loup Martin!

It seems like the physics of silicon long ago replaced the chemistry of silver as the primary means of creating photographs, to the point where few of us even have film cameras anymore, and home darkrooms are a relic of the deep past. Nobody doubts that the ability to snap a quick photo or even to create a work of photographic genius with a tiny device that fits in your pocket is a wonder of the world, but still, digital photographs can lack some of the soul of film photography.

Recapturing the look of old school photography is a passion for a relatively small group of dedicated photographers, who ply their craft with equipment and chemistries that haven’t been in widespread use for a hundred years. The tools of this specialty trade are hard to come by commercially, so practitioners of alternate photographic processes are by definition hackers, making current equipment bend to the old ways. Pierre-Loup is one such artist, working with collodion plateshacked large-format cameras, pinholes camera, and chemicals and processes galore –  anything that lets him capture a unique image. His photographs are eerie, with analog imperfections that Photoshop would have a hard time creating.

Join us as Pierre-Loup takes us on a tour through the world of alternative photography. We’ll look at the different chemistries used in alternative photography, the reasons why anyone would want to try it, and the equipment needed to pull it off. Photography was always a hack, until it wasn’t; Pierre-Loup will show us how he’s trying to put some soul back into it.

join-hack-chatOur Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday, October 2 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.