Graphene Biosensors are Extra Quiet

Graphene has attracted enormous interest for electrically detecting chemical and biological materials. However, because the super material doesn’t act like a normal semiconductor, transistors require multiple layers of the material, and that’s bad for 1/f noise especially when the transistors operate at maximum transconductance. Researchers have found a way to operate graphene transistors at a neutral point, significantly reducing 1/f noise while not impacting the sensor’s response.

The team created a proof-of concept sensor that could detect an HIV-related DNA hybridization. The sensor was able to detect very tiny concentrations of the material.

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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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Making Braille Signs out of PCBs

[jg] recently passed some damaged Braille signs and took on the challenge of repairing them. Informed by his recent work on PCB lapel pins, [jg] immediately thought of using circuit boards for this project. He’d noticed that round solder pads made for uniform hills of solder, and this reminded him of the bumps in Braille.

He began by reading up on the standards of the Braille Authority of North America, which stipulates a dot height of 0.6mm. He loaded up the PharmaBraille font system and laid it out the dots in photoshop, then and imported it into KiCad and laid out the boards. When the PCBs had arrived from OSH Park, [jg] soldering up the pads (lead free, but of course) to see if he could get the hills to 0.6mm. He’s experimenting with different methods of melting the solder to try to get more even results.

Braille interfaces crop up a surprising amount in hacker projects. This refreshable Braille display and keyboard and the Braigo LEGO Braille printer are prime examples.

[thanks, Drew!]

Homebuilt Laser Engraver Using Salvaged Parts

Now that anyone can go online and get a fairly decent 3D printer for around $200, they’ve officially fallen out of the “Elite Hacker” arsenal and are now normal, if perhaps highly specialized, tools. That’s great for the 3D printing community as a whole, but what about those who want to be on the fringe of technology? Telling people you have a 3D printer at home doesn’t get that wide-eyed response like it used to. What’s a “l33t” hacker to do?

Enter the laser engraver/cutter: it’s like a 3D printer, but easier to build and has a higher capacity for bodily harm! While there are a couple good options for kits and turn-key setups out there, just like the early days of 3D printers, some of the best machines are still home built. In his latest video, YouTuber [MakerMan] takes us through his build which features an impressively low part count.

To start his build, [MakerMan] strips down four printers and salvages seven high quality 8 mm linear rods; a huge cost saving tip in itself. We’ll certainly be picking up any printers we see in the trash for the next couple months hoping to score some rods. With the addition of some cheap LM8UU bearings and 3D printed holders for them, [MakerMan] has a smooth 2D motion platform for just a couple bucks. The frame of the machine is built out of type of aluminum square tubing you can find at the hardware store, no expensive extrusion here.

For the laser itself, [MakerMan] is using a six watt PLH3D-6W-XF from Opt Lasers. This module features integrated driver and cooling, so all you need to do is provide it power and a stable means of moving it over the work piece. They even offer a magnetic “dock” which allows you to remove the laser from the mount without any tools for servicing or tool changes. [MakerMan] reports he’s been able to engrave stainless steel with this laser module, and cut thin wood.

This isn’t the first laser engraver we’ve seen built out of scrap parts, though if you want to save some work you could just upgrade a cheap commercial model.

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Hackaday Prize Entry: Radio Telescope Interferometer

Radio telescopes are one of the dark arts of science. Not only do you have to deal with RF wizardry, the photons you’re detecting are so far out of the normal human experience that you really don’t know what you’re looking at. It’s hard, but that’s the point — there’s a lot to learn with a radio telescope.

[alfazoOm]’s entry in the 2017 Hackaday Prize seeks to counteract a two-part problem: first, there is a dearth of educational radio interferometers in Latin America. Secondly, in Colombia, there’s only so much clear sky so radio astronomy is the preferred technique. Even though they’re so close to the equator, a lot of the northern stars can be seen as well. His interferometer, IMFR11GHz, answers both of those challenges.

IMFR11GHz is a Michelson interferometer, in which a light source is split into two beams, which are reflected by mirrors back to the detector. [alfazoOm] is basing his telescope off of the Stony Brook radio interferometer, though he is designing custom hardware that can position the dish in whatever direction the operator desires with an Alt-Az mount. The control system consists of an ESP32 microcontroller with an IMU and two stepper motors controlling azimuth and elevation. This is awesome citizen science, and a great entry in the Hackaday Prize.

Rita Levi-Montalcini Had Nerves of Steel

When we think of role models, it’s easy to categorize them narrowly on the basis of their skill set. We might say that he’s a great mathematician, or that she is an excellent chemist. Some role models are admirable on a deeper, human level. These are the kinds of heroes who obliterate all the obstacles dropped in front of them to tirelessly pursue their interests and devote their lives to doing the kind of stuff that makes the world better for everyone.

Italian Nobel Laureate Rita Levi-Montalcini is this kind of role model. Her scientific curiosity and unconventional thinking led her to discover nerve growth factor (NGF), a naturally occurring protein which we now know is responsible for nerve growth and regulation. Rita’s discovery provided great insight into the way the nervous system develops. The discoveries that she made underlie much of modern research into neurologically degenerative diseases like Alzheimer’s and cancer, and NGF is used experimentally the treatment of both.

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Mike Harrison’s Reverse Engineering Workshop

Hardware teardowns are awesome when guided by experts. One of our favorites over the years has been [Mike Harrison], who has conquered teardowns of some incredibly rare and exquisitely engineered gear, sharing the adventure on his YouTube channel: mikeselectricstuff. Now he’s putting on a workshop to walk through some of the techniques he uses when looking at equipment for the first time.

[Mike] will be in Pasadena a few days early for the Hackaday Superconference and floated the idea of hosting a workshop. We ordered up some interesting gear which he hasn’t had a chance to look at yet. A dozen lucky workshop attendees will walk through the process [Mike] uses to explore the manufacturing and design choices — skills that will translate to examining any piece of unknown gear. He may even delve into the functionality of the equipment if time allows. Get your ticket right now!

To keep things interesting we’re not going to reveal the equipment until after the fact. But follow the event page where we’ll publish the details of his reverse engineering work after the workshop.

[Mike] is the badge designer for this year’s Hackaday Superconference badge. Unfortunately Supercon is completely sold out (we tried to warn you) but you can check out the badge details he already published. And we will be live streaming the Supercon this year — more details on that next week!