A Year-Long Experiment In OLED Burn-In

April 23, 2019 by 26 Comments

If you need to add a small display to your project, you’re not going to do much better than a tiny OLED display. These tiny display are black and white, usually found in resolutions of 128×64 or some other divisible-by-two value, they’re driven over I2C, the libraries are readily available, and they’re cheap. You can’t do much better for displaying a few numbers and text than an I2C OLED. There’s a problem, though: OLEDs burn out, or burn in, depending on how you define it. What’s the lifetime of these OLEDs? That’s exactly what [Electronics In Focus] is testing (YouTube, in Russian, so click the closed captioning button).

The experimental setup for this is eleven OLED displays with 128×64 pixels with an SSD1306 controller, all driven by an STM32 over I2C. Everything’s on a breadboard, and the actual display is sixteen blocks, each lit one after another with a one-second display in between. This is to test gradually increasing levels of burnout, and from a surface-level analysis, this is a pretty good way to see if OLED pixels burn out.

After 378 days of testing, this test was stopped after there were no failed displays. This comes with a caveat: after a year of endurance testing, there were a few burnt out pixels. correlating with how often these pixels were on. The solution to this problem would be to occasionally ‘jiggle’ the displayed text around the screen, turn the display off when no one is looking at it, or alternatively write a screen saver for OLEDs. That last bit has already been done, and here are the flying toasters to prove it. This is an interesting experiment, and although that weird project you’re working on probably won’t ping an OLED for a year of continuous operation, it’s still something to think about. Video below.

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3D Printing A Real Heart

April 23, 2019 by 12 Comments

As 3D printing becomes more and more used in a wide range of fields, medical science is not left behind. From the more standard uses such as printing medical equipment and prosthetics to more advanced uses like printing cartilages and bones, the success of 3D printing technologies in the medical field is rapidly growing.

One of the last breakthrough is the world’s first 3D vascularised engineered heart using the patient’s own cells and biological materials. Until now, scientists have only been successful in printing only simple tissues without blood vessels. Researchers from Tel Aviv University used the fatty tissue from patients to separate the cellular and acellular materials and reprogrammed the cells become pluripotent stem cells. The extracellular matrix (ECM) was processed into a personalized hydrogel that served as the basis from the print.

This heart is made from human cells and patient-specific biological materials. In our process these materials serve as the bioinks, substances made of sugars and proteins that can be used for 3D printing of complex tissue models… At this stage, our 3D heart is small, the size of a rabbit’s heart, but larger human hearts require the same technology.

After being mixed with the hydrogel, the cells were efficiently differentiated to cardiac or endothelial cells to create patient-specific, immune-compatible cardiac patches with blood vessels and, subsequently, an entire heart that completely matches the immunological, cellular, biochemical and anatomical properties of the patient. The difficulty of printing full-blown organs were being tackled for a long time and we already talked about it in the past.

The development of this technology may completely solve both the problem of organ compatibility and organ rejection.

 

Get Coding With This Atari 2600 Development Suite

April 22, 2019 by 18 Comments

Sometimes the urge strikes to get busy coding for an old retro system, but unfortunately the bar to entry can be high. There’s a need to find a workable compiler, let alone trying to figure out how to load code onto original vintage hardware. It doesn’t have to be so hard, though. The team at [HeatSync Labs] built an Atari 2600 development station so hackerspace members can simply rock up and get to work.

With this rig, development is a multi-step process. A paper manual is on hand to provide detail of how to code for the Atari. An IBM PC is then on hand to allow the budding developer to code in assembly. This text file is then compiled into an Atari ROM, which is then passed through a special utility to convert it to an audio file. This is to allow it to be used with a Starpath Supercharger, which allows games to be loaded onto the Atari via cassette tape, or in this case, raw digital audio. By playing the audio file on the PC, connected to the Supercharger cartridge, it’s possible to run arbitrary code on the Atari 2600.

Programming in 6502 assembly isn’t the easiest mountain to climb for an absolute novice, but experienced coders will likely appreciate the no-fuss development environment. It makes for an easy gateway into the world of retro console programming, and there’s nothing like the fun of seeing your code running on original hardware.

We love a good story of retro development – like this tale of fixing a 37-year-old bug in an Apple II game. Video after the break.

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Mechanical Integration With KiCad

April 22, 2019 by 20 Comments

Eagle and Fusion are getting all the respect for integrating electronic and mechanical design, but what about KiCad? Are there any tools out there that allow you to easily build an enclosure for your next printed circuit board? [Maurice] has one solution, and it seamlessly synchronizes KiCad and FreeCAD. KiCad will give you the board, FreeCAD will give you the enclosure, and together you have full ECAD and MCAD synchronization.

This trick comes in the form of a FreeCAD macro (on the Github, with a bunch of documentation) that loads a KiCad board and components into FreeCAD and export them as a STEP file. You can align the KiCad board in FreeCAD, convert STEPs to VRMLs, check interference and collision, and create an enclosure around a KiCad board.

KiCad has gotten some really great visualization tools over the past few years, and we would be remiss if we didn’t mention it’s one of the best ways to visualize a completed circuit board before heading to production. Taking that leap from electronic CAD to mechanical CAD is still something that’s relatively rare in the KiCad ecosystem, and more tools to make this happen is always wanted.

Steel-Reinforced 3D Prints

April 22, 2019 by 17 Comments

Continuing on the never-ending adventure of how to make a 3D print stronger, [Brauns CNC] is coming at us with a new technique that involves steel-reinforced 3D printed parts.

We’ve seen plenty of methods to create stronger 3D prints, from using carbon fiber filament to simply printing the part in a way that the layers of the print are orthogonal to the direction of force. We’ve even seen casting carbon fiber bars into 3D prints, but of course that will only work with straight parts. [Brauns]’ technique uses steel wire, embedded into the print itself, and from some testing there’s about a 50% increase in strength of the part.

The process of embedding a steel cable into a 3D printed part is simply taking apart the model and putting a channel in for the cable. At a specific layer height, the printer is stopped, the steel cable is embedded with the help of a soldering iron, and the printer continues doing its thing.

There’s a slight amount of Gcode hacking to make this happen, and the process of embedding a steel cable into a print is a bit finicky. Still, if you want stronger 3D prints, there are worse ways to do it, and certainly less effective ways of doing it. You can check out the video for this technique below.

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JigFab Makes Woodworking Easier

April 22, 2019 by 20 Comments

Woodworking is an age-old craft that requires creativity and skill to get the best results. Experienced hands get the best results, while the new builder may struggle to confidently produce even basic pieces. JigFab is here to level the playing field somewhat.

Much of the skill in woodworking comes with mastering the various joints and techniques required to hold a piece together. Cutting these joints often requires specialized tools and equipment – ideally, some sort of jig. These jigs can be difficult to build in themselves, and that’s where JigFab shines.

The workflow is straightforward and quite modern. A piece is designed in Autodesk Fusion 360. Various joints can then be defined in the model between individual parts. JigFab then generates a series of laser cut constraints that can be used with power tools to easily and accurately cut the necessary parts to build the final piece.

It’s an impressive technology which could rapidly speed the workflow of anyone experimenting with woodwork and design. There’s even smart choices, like having a toolkit of standard predefined elements that reduce laser cutting time when producing new constraints. If you’re eager to get stuck in to woodwork, but don’t know where to start, don’t worry – we’ve got a primer for that. Video after the break.

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Power Stacker, A Modular Battery Bank

April 22, 2019 by 9 Comments

Many of us will own a lithium-ion power pack or two, usually a brick containing a few 18650 cylindrical cells and a 5 V converter for USB charging a cellphone. They’re an extremely useful item to have in your carry-around, for a bit of extra battery life when your day’s Hackaday reading has provided a worthy use for most of your charge. These pack are though by their very nature inflexible, no matter how many cells you own, the pack will only ever contain the number with which it was shipped. Worse, when those cells are discharged or even  reach the end of their lives, they can’t be swapped for fresh ones. [Isaacporras] has a solution for these problems which he calls the Power Stacker, a modular battery pack system.

At its heart is the Maxim MAX8903 lithium-ion charge controller chip, of which one is provided for each cell. A single cell and MAX8903 with a DC to DC converter for 5 V output makes for the simplest configuration, and he has a backplane allowing multiple boards to be connected and sharing the same charge and output buses.

An infinitely configurable battery bank sounds great. It’s looking for crowdfunding backing, and for that it has an explanatory video which you can see below. Meanwhile if you’d  like to try for yourself you can find the necessary files on the hackaday.io page linked above.

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