[Ben Krasnow] Tests Novel Plasma

When [Ben Krasnow] sees an interesting phenomenon he pursues it with a true scientist’s mentality, though it doesn’t hurt that he also has the skills and the workshop. This time he’s produced a glowing plasma by impacting fused quartz and other materials with a high-speed water jet.

The jet of pure water emerges from a 0.004″, or 100 micron, diameter sapphire orifice with a flow rate of around 2 milliliters per second giving a speed of 240 meters per second. It collides at 90° with a dielectric material where the plasma is produced as a toroid surrounding the collision point.

How a waterjet plasma works
How a waterjet plasma works

There’s been very little research into the phenomena but a proposal from one research paper which [Ben] found is that the plasma is a result of charging due to the triboelectric effect. This is the same effect which charges a balloon when you rub it against your hair, except that here there are water molecules running across a clear dielectric such as fused quartz. This effect results in a positively charged anode downstream of the collision while the water near the point of highest shear becomes conductive and conducts negative charge to the point of smallest curvature, producing a cathode. The electric field at the small-radius cathode acts like a short point with a high voltage on it, ionizing the air and forming the plasma. If this form of ionization sounds familiar, that’s because we’ve talked it occurring between the sharp wire and rounded foil skirt of a flying lifter.

[Ben] found support for the triboelectric theory when he substituted oil for the water. This didn’t produce any plasma, which is be expected since unlike water, oil is a non-polar molecule. However, while the researchers tried just a few dielectric materials, [Ben] had success with every transparent dielectric which he tried, including fused quartz, lithium niobate, glass, polycarbonate, and acrylic, some of which are very triboelectrically different from each other. So there’s room here for more theorizing. But check out his full video showing his equipment for producing the waterjet as well as his demonstrations and explanation.

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[Ben Krasnow] Hacks E-Paper For Fastest Refresh Rate

[Ben Krasnow] is known for his clear explanations alongside awesome hardware, being one of only a few hackers who owns an electron microscope. This time he’s explaining how E-paper works while modifying the firmware of a 4.2 inch E-paper module to get a higher refresh rate. As for the awesome hardware, he also analyses the signals going to the E-paper using an ultra-fancy loaner oscilloscope.

E-paper explanation diagram
E-paper explanation diagram

After starting out with a demo of the firmware in action before and after his modification, he explains how the E-paper works. The display is made up of many isolated chambers, each containing charged particles in a liquid. For example, the positive particles might be black and the negative might be white. By putting an electric field across each chamber, the white particles would be attracted to one end while the black would be attracted to the other, which could be the end you’re looking at. He also explains how it’s possible to get a third color by using different sized particles along with some extra manipulation of the electric field. And he talks about the issue of burn-in and how to avoid it.

Having given us that background, he then walks us through some of the firmware and shows how he modified it to make it faster, namely by researching various datasheets and subsequently modifying some look-up-tables.

Turning back to the hardware, he shows how he scratches out some traces so that he can attach scope probes. This alone seems like a notable achievement, though he points out that the conductive layer holds up well to his scratching. At that point he analyses the signals while running some demos.

The result is the very informative, interesting and entertaining video which you can watch below.

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Superconference Interview: Ben Krasnow

Ben Krasnow is a consummate prototyper. He’s built a machine that makes the perfect chocolate chip cookie, he has a ruby laser, and he produces his own liquid nitrogen in-house because simply filling up a dewar is too easy. If you need a prototype, Ben is the guy to talk to.

Ben gave a talk at last year’s Hackaday Superconference on prototyping quickly and verifying technical hypotheses. The philosophy can be summed up simply as, ‘Build First, and Ask Questions Later’. This philosophy served him well when he wanted to see if backscatter x-ray machines were actually more effective than metal detectors at TSA checkpoints. The usual bean-counter protocol for answering this question would be to find an x-ray expert, wait weeks, pay tens of thousands of dollars, and eventually get an answer. Ben simply built his own backscatter x-ray machine from parts sourced on eBay.

After the talk, we asked Ben about the limits of this philosophy of building first and asking questions later. With the physical and mental toolset Ben has, it’s actually easy to build something that can get in the ballpark of answering a question. The problem comes when Ben needs to prove something won’t work.

Answering this question is all a matter of mindset. In Ben’s view, if a prototype works, a hypothesis is verified. Even if it’s a complete accident, he’s totally okay with the results. Some of his other colleagues have an opposite mindset — if a quick and dirty prototype doesn’t work, a research hypothesis is verified.

This rapid-proof-of-concept mindset is something we see a lot in the Hackaday audience, and we know there are some of you out there who have a mind and garage that is at least as impressive as Ben’s. We’ve extended the Call for Proposals for the 2017 Hackaday Superconference. If you have a story about rapid prototyping or just making the perfect chocolate chip cookie with robots, we want to hear about it. Tickets are still available for the Superconference in Pasadena, California on November 11th and 12th.

Quickly Prototyping X-ray Backscatter Machines

Ben Krasnow is one of those people no one has a bad opinion of. He’s part of the team at Verily (Google’s Life Science Alphabit), where he’s busy curing cancer. He co-founded Valve’s hardware division and his YouTube channel, Applied Science, is an exploration of building very high-tech tools very quickly and on a very low budget. Ben has built everything from an electron microscope to a liquid nitrogen generator to a robot that makes individual chocolate chip cookies with ingredients in different proportions. He’s curing cancer and finding the perfect chocolate chip cookie recipe.

The focus of Ben’s talk at this year’s Hackaday SuperConference is building low-cost scientific apparatus quickly. From Applied Science, Ben has cemented his position as a wizard who can find anything either on eBay or at a surplus store. The real trick, Ben tells us, is getting his boss and accounting to understand this rapid prototyping mindset.

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Get Your Ticket to SuperCon, the Greatest Hardware Creation Con

The world’s most excellent conference on hardware creation, the Hackaday SuperConference, is back. Get your tickets now for two magical days in Pasadena this November.

This exclusive gathering of hackers, designers, and engineers is where brilliant people geek out with their peers. Talks tell the story of research, prototyping, product design, manufacturing, and getting that new hardware out into the world. Nowhere else can you get such a concentrated dose of Sistine-Chapel-like details about what is being built in businesses small and large, basements, University labs, and everywhere else.

Early tickets are $128, get your pass to the conference now! This ticket gets you in the door for talks, breakfast and lunch on both days, a conference badge, and the party on Saturday night. SuperCon also includes hands-on workshops — these have limited capacity and some have material costs, more about this next week.

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A Refrigerator Cooled by Rubber Bands

Ever noticed that a rubber band gets warmer when it’s stretched? The bands also get cooler when allowed to snap back to relaxed length? [Ben Krasnow] noticed, and he built a rubber band cooled refrigerator to demonstrate the concept. The idea of stretching a rubber band to make it hotter, then releasing it to make it cooler seems a bit counter intuitive. Normally when things get smaller (like a gas being compressed) they get hotter. When pressure is released the gas gets cooler. Rubber bands do the exact opposite. Stretching a rubber band makes it hot. Releasing the stretched band causes it to get cooler.

No, the second law of thermodynamics isn’t in jeopardy. The secret is in the molecular structure of rubber bands. The bands are made of long polymer chains. A relaxed rubber band’s chains are a tangled mess. Stretching the band causes the chains to untangle and line up in an orderly fashion. By stretching the band you are decreasing its entropy. The energy of the molecules in the band don’t change, but entropy does. All the work one does to stheatwheelretch the band has to go somewhere, and that somewhere is heat. This is all an example of entropic force. For a physics model of what’s going on, check out ideal chains. If you’re confused, watch the video. [Ben] does a better job of explaining entropic force visually than we can with text.

To test this phenomenon out, [Ben] first built a wheel with rubber bands as spokes. Placing the wheel in front of a heater caused it to slowly rotate. [Ben] then reversed the process by building a refrigerator. He modeled his parts in solidworks, then cut parts with his Shaper handheld CNC. The fridge itself consists of an offset wheel of rubber bands. The bands are stretched outside the fridge, and released inside. Two fans help transfer the thermal energy from the bands to the air. The whole thing is hand cranked, so this would make a perfect museum or educational demonstration. Cranking the fridge for 5 minutes did get the air inside a couple of degrees cooler. Rubber is never going to displace standard refrigerants, but this is a great demo of the principles of entropic force.

For more thermodynamic fun, check out [Al Williams] recent article about building a DIY heat pipe.

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Hackaday Links: April 17, 2016

There have been really cool happenings in the CNC world for the past few years. There is a recent trend of portable, handheld CNC machines. Yes, you read that correctly. This SIGGRAPH paper demonstrated a handheld router with a camera and a few motors that would make slight corrections to the position of the router. Load in a .DXF or other vector file, and you become the largest CNC machine on the planet. We saw it at one of the Maker Faires, and about a year ago the team soft launched. Apparently, the Shaper router is gearing up for production and [Ben Krasnow] got the first look with a full 17-minute demonstration of [Ben] fabricating parts out of aluminum. It looks like a great tool, and we can’t wait to see this thing in production.

Octoprint is the best way to give a 3D printer a web interface. The dev for Octoprint, [Gina Häußge] used to have a sponsor for developing Octoprint. They’re gone now, which means it’s time for [Gina] to start a Patreon. If you use Octoprint, you know it’s worth more than a dollar a month.

Really bad USB power supplies are nothing new around these parts. There are cheap USB supplies that don’t have any fuses, don’t have any circuit protection, and are noisy as hell. This is the worst USB power supply the Internet has to offer. It’s from one of the relatively new designs of USB power supplies that steps down mains voltage to five USB A ports. [bigclive]’s teardown revealed this was passing half wave mains voltage to the USB ports. It can light up a light bulb. It can kill your phone. The fault? A pinhole in the insulation between the windings of the transformer.

Electronic conference badges are getting excessive, but they can be so much cooler. Here’s Atmel’s take on a high-end conference badge. It has a display, sensors, WiFi, Bluetooth, runs Android, and has 512MB of RAM, 4GB of Flash. It’s a freakin’ mini tablet meant to last for three days.

Speaking of Atmel, they’re having a few growing pains in the merger with Microchip. Employees coming to Microchip from Atmel are getting their severance benefits cut in half. Apparently, the severance benefits given to Atmel employees were not communicated to Microchip before the merger.

Raspberry Pi Zeros are back in production. There’s also going to be a mysterious new feature. Is it WiFi? No, it’s confirmed not to be WiFi. How about Ethernet? Bluetooth? an RTC? Full size HDMI port? Actual pin headers? Audio port? Improved CPU / RAM? No, children. It’s none of these.

C.H.I.P., the nine dollar computer that made some waves last summer, has on-board Flash storage. That means you don’t need to put an image on an SD card. The folks behind C.H.I.P. have recently improved the method for flashing a new OS onto their tiny board: a Chrome plugin. Yes, this sounds completely bizarre, but Chrome plugins are becoming increasingly popular for USB gadget wizardry. You can program an Arduino with Chrome and log USB power profiles with a USB tester and Chrome. You will ride eternal, shiny and chrome.