Plasma “Ghosts” May Help Keep Future Aircraft Safe

May 18, 2020 by Tom Nardi 34 Comments

Air-to-air combat or “dogfighting” was once a very personal affair. Pilots of the First and Second World War had to get so close to land a hit with their guns that it wasn’t uncommon for altercations to end in a mid-air collision. But by the 1960s, guided missile technology had advanced to the point that a fighter could lock onto an enemy aircraft and fire before the target even came into visual range. The skill and experience of a pilot was no longer enough to guarantee the outcome of an engagement, and a new arms race was born.

An F-15 launching flare countermeasures.

Naturally, the move to guided weapons triggered the development of defensive countermeasures that could confuse them. If the missile is guided by radar, the target aircraft can eject a cloud of metallic strips known as chaff to overwhelm its targeting system. Heat-seeking missiles can be thrown off with a flare that burns hotter than the aircraft’s engine exhaust. Both techniques are simple, reliable, and have remained effective after more than a half-century of guided missile development.

But they aren’t perfect. The biggest problem is that both chaff and flares are a finite resource: once the aircraft has expended its stock, it’s left defenseless. They also only work for a limited amount of time, which makes timing their deployment absolutely critical. Automated dispensers can help ensure that the countermeasures are used as efficiently as possible, but sustained enemy fire could still deplete the aircraft’s defensive systems if given enough time.

In an effort to develop the ultimate in defensive countermeasures, the United States Navy has been working on a system that can project decoy aircraft in mid-air. Referred to as “Ghosts” in the recently published patent, several of these phantom aircraft could be generated for as long as the system has electrical power. History tells us that the proliferation of this technology will inevitably lead to the development of an even more sensitive guided missile, but in the meantime, it could give American aircraft a considerable advantage in any potential air-to-air engagements.

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ESP32 Trail Camera Goes The Distance On AA Batteries

May 18, 2020 by Tom Nardi 34 Comments

There’s no shortage of things to like about the ESP8266 and ESP32, but if we had to make a list of the best features these WiFi-enabled microcontrollers have to offer, their power management capabilities would certainly be near the top. Which is how we assumed [Mark] was able to take a whopping 23,475 pictures on his ESP32 camera while powered by nothing more exotic than four AA batteries from the grocery store.

But as it turns out, the full story is quite a bit more interesting. As far as we can tell, [Mark] isn’t bothering with the ESP32’s sleep modes all. In fact, it looks like you could pull this trick off with whatever chip you wanted, which certainly makes it worth mentally filing away for the future; even if it depends on a fairly specific use case.

In the most simplistic of terms, [Mark] is cutting power to the ESP32 completely when it’s not actively taking pictures. The clever circuit he’s come up with only turns on the microcontroller when a PIR sensor detects something moving around in front of the camera. Once the chip is powered up and running code, it brings one of its GPIO pins high which in turn triggers a 4N37 optoisolator connected to the gate on the circuit’s MOSFET. As long as the pin remains high, the circuit won’t cut power to the ESP32. This gives the chip time to take the requested number of pictures and get everything in order before bringing the pin low and allowing the circuit to pull the plug.

If you’re looking to maximize runtime without wrangling any MOSFETs, we’ve seen some excellent examples of how the low power modes on the ESP8266 and ESP32 can be put to impressive use.

[Thanks to Jason for the tip.]

Force Feedback Mouse Really Shakes Things Up

May 17, 2020 by Tom Nardi 21 Comments

This is a very exciting time for those who like to spend their downtime exploring virtual worlds. The graphics in some big-budget titles are easily approaching photorealism, and immersive multi-channel sound can really make you believe you’ve been transported to another place or time. With another generation or two of GPU development and VR hardware, the line between gaming and reality is bound to get awful blurry.

That said, we’re still a far way off from the holodeck aboard the Enterprise. A high-end PC and the latest in VR can fool your eyes and ears, but that still leaves your other senses out of the fun. That’s why [Jatin Patel] has developed this clever force-feedback mouse using an array of solenoids.

The idea is pretty simple: a Python program on the computer listens for mouse click events, and tells an attached Arduino to fire off the solenoids when the player pulls the virtual trigger. It’s naturally not a perfect system, as it would seem that clicking in the game’s menus would also start your “gun” firing. But as you can see in the video after the break, when it works, it works very well. The moving solenoids don’t just vibrate the mouse around, the metallic clacking actually accentuates the gun sound effects from the game.

With this kind of tactile feedback and an omnidirectional treadmill to keep us moving, we’d be pretty close to fooling our senses into thinking we’re actually somewhere else. Which frankly, sounds quite appealing right about now.

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High Voltage Experiment Pipes Power With Water

May 15, 2020 by Tom Nardi 27 Comments

The idea of transferring energy with water isn’t exactly new. In fact, it’s downright ancient. Running water has been tapped to power our contrivances since folks were getting excited about that new library they were opening up over in Alexandria. But what if there was a way to deliver power with water that wasn’t kinetic, and instead relied on the electrical properties of the planet’s favorite libation?

That’s exactly what [Jay Bowles] set out to explore with his latest experiment. Since water (we know, not pure water) conducts electricity, it stands to reason that it could be used as a stand-in for traditional copper wiring. Why would you want to do such a thing? Because unlike wires, water can easily morph into whatever shape may be required, and can be moved around and controlled with nothing more complex than ball valves.

To test this concept, [Jay] put together a water distribution system out of simple acrylic tubing. A reservoir was attached to one of his high voltage generators, and copper caps were placed at the end of the tubes to serve as direct attachment points for devices.

But thanks to capacitive coupling, the fluorescent lights he uses don’t actually need to be physically connected to light up. As demonstrated in the video after the break, the lights surrounding the system can be independently controlled just by turning their respective valves on and off; all without any physical contact being made.

Of course, compared to traditional wiring there are plenty of downsides to this idea. Copper wires don’t tend to freeze in the winter and spring a leak, nor do they build up bubbles of explosive hydrogen gas. So it’s safe to say the wiring in your house probably won’t ever be replaced with a tube of charged water. But [Jay] does have some interesting ideas of how this technique could be used in non-traditional ways. For example, he describes how outdoor lighting could be powered by the energy radiating from a small stream.

Even if the practical applications of this technique are somewhat limited, there’s no question that it’s a fascinating idea. Believing that he’s the first person to ever demonstrate power transmission under these specific circumstances, he’s decided to call the concept “Bowles Transmission”. We’d love to see somebody use this principle in one of their projects, and we’re willing to bet so would [Jay].

As with his recent ozone sterilization experiments, we imagine this idea is going to be met with some debate. But that’s sort of the point. [Jay] doesn’t claim to have all the answers, and hopes these videos get people thinking and talking. As they say, nothing great was ever achieved without enthusiasm.

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All Your Passwords Are Belong To FPGA

May 15, 2020 by Tom Nardi 26 Comments

When used for cracking passwords, a modern high-end graphics card will absolutely chew through “classic” hashing algorithms like SHA-1 and SHA-2. When a single desktop machine can run through 50+ billion password combinations per second, even decent passwords can be guessed in a worryingly short amount of time. Luckily, advanced password hashing functions such as bcrypt are designed specifically to make these sort of brute-force attacks impractically slow.

Cracking bcrypt on desktop hardware might be out of the question, but the folks over at [Scattered Secrets] had a hunch that an array of FPGAs might be up to the task. While the clock speed on these programmable chips might seem low compared to a modern CPUs and GPUs, they don’t have all that burdensome overhead to contend with. This makes the dedicated circuitry in the FPGA many times more efficient at performing the same task. Using a decade-old FPGA board intended for mining cryptocurrency, the team was able to demonstrate a four-fold performance improvement over the latest generation of GPUs.

After seeing what a single quad FPGA board was capable of, the [Scattered Secrets] team started scaling the concept up. The first version of the hardware crammed a dozen of the ZTEX FPGA boards and a master control computer computer into a standard 4U server case. For the second version, they bumped that up to 18 boards for a total of 72 FPGAs, and made incremental improvements to the power and connectivity systems.

Each 4U FPGA cracker is capable of 2.1 million bcrypt hashes per second, while consuming just 585 watts. To put that into perspective, [Scattered Secrets] says you’d need at least 75 Nvidia RTX-2080Ti graphics cards to match that performance. Such an array would not only take up a whole server rack, but would burn through a staggering 25 kilowatts. Now might be a good time to change your password to something longer, or finally get onboard with 2FA.

We’ve covered attempts to reverse engineer hardware designed for cryptocurrency mining, but those were based around application-specific integrated circuits (ASICs) which by definition are very difficult to repurpose. On the other hand, disused FPGA-based miners offer tantalizing possibilities; once you wrap your mind around how they work, anyway.

[Thanks to Piejoe for the tip.]

An ESP32 Home Automation Swiss Army Knife

May 14, 2020 by Tom Nardi 37 Comments

Thanks to the ESP8266 and the ESP32, we’ve seen an explosion in DIY home automation projects recently. When it only takes $3 and a few lines of code to bring your gadgets onto the network, that’s hardly a surprise. But hacking bare ESP modules onto devices will only get you so far. Eventually you’ll probably want to put together a slightly more mature home automation system, and that’s where things can get a little tricky.

Which is why [Alfredo] created the Maisken Homelay. This device is a one-stop-shop for your home automation needs that leverages the power of the ESP32. With the microcontroller slotted into this compact PCB, you’ll be able to trigger four relays for your high current or AC loads, and still have 8 GPIOs and the I2C bus for expansion. All while retaining compatibility with existing open source projects like Home Assistant and ESPHome.

What really sets this project apart is the attention to detail. [Alfredo] has included a HLK-PM01 power supply on the board which takes mains voltage and brings it down to 5 VDC for the ESP32, so won’t need a separate power cable. He’s also taken the time to add isolation slots to separate the potential high-voltage connected to the relays from the rest of the board, added current and thermal fuses for protection, and peppered the board with screw terminals so you can easily connect everything up.

Sure you could get a simple relay board shipped to your door for a few bucks from the usual suspects. But it’s not going to offer the kind of quality of life and safety features that the Maisken Homelay has. There’s even a 3D printed enclosure available to help tidy things up.

With some of the blatantly anti-consumer decisions big-name home automation companies have been making recently, there’s more reason than ever to roll your own smart home using open source hardware and software. It still takes more effort than buying a bunch of modules from the Big Box retailer, but projects like this one are certainly starting to blur the line between consumer and DIY.

Fusing Plastic Sheets With A 3D Printer (Sort Of)

May 14, 2020 by Tom Nardi 17 Comments

If you want to experiment with pneumatic devices, you’ll likely find yourself in need of custom inflatable bladders eventually. These can be made in arbitrary 2D shapes by using a soldering iron to fuse the edges of two plastic sheets together, but it’s obviously a pretty tedious and finicky process. Now, if only there was some widely available machine that had the ability to accurately apply heat and pressure over a large surface…

Realizing his 3D printer had all the makings of an ideal bladder fusing machine, [Koppany Horvath] recently performed some fascinating experiments to test this concept out in the real-world. Ultimately he considers the attempt to be a failure, but we think he might be being a bit too hard on himself. While he didn’t get the sheets to fuse hard enough to resist being pulled apart by hand, we think he’s definitely on the right track and would love to see more research into this approach.

For these early tests, [Koppany] wrapped the hotend of his Monoprice Maker Select Plus with some aluminum foil, and covered the bed with a piece of cardboard. Stretched over this were two sheets of plastic, approximately 0.5 mil in thickness. Specifically, he used pieces cut from the bags that his favorite sandwiches come in; but we imagine you could swap it out for whatever bag your takeout of choice is conveyed in, assuming it’s of a similar thickness anyway.

There were problems getting the plastic pulled tight enough, but that was mostly solved with the strategic placement of binder clips and a cardboard frame. Once everything was in place, [Koppany] wrote a Python script that commanded the printer to drag the hotend over the plastic at various speeds while simultaneously adjusting the temperature. The goal was to identify the precise combination of these variables that would fuse the sheets of plastic together without damaging them.

In the end, his biggest takeaway (no pun intended) was that the plastic he was using probably isn’t the ideal material for this kind of process. While he got some decent seams at around 180 °C , the thin plastic had a strong tendency towards bunching up. Though he also thinks that a convex brass probe inserted into the hotend could help, as it would smooth the plastic while applying heat.

We’ve already seen some very promising results when using LDPE film in a CO2 laser cutter, but if a entry-level 3D printer could be modified to produce similar results, it could be a real game changer for folks experimenting with soft robotics.