The Future’s So Bright, You Gotta Wear Arduglasses

Tiny OLED displays are an absolute must-have in the modern parts bin, so what better way to show your allegiance to the maker movement than with a pair of Arduino-compatible OLED glasses? Created by Arduboy mastermind [Kevin Bates], these digital spectacles might not help you see any better — in fact, you’ll see a bit worse — but they’ll certainly make you stand out in the crowd at the next hacker con. (Whenever we can have one of those again, anyway.)

The key to this project is a pair of transparent CrystalFonts OLED displays, just like the ones [Sean Hodgins] recently used to produce his gorgeous volumetric display. In fact, [Kevin] says it was his success with these displays that inspired him to pursue his own project. With some clever PCB design, he came up with some boards that could be manufactured by OSH Park and put together with jewelry box hinges. Small flexible circuits, also from OSH Park, link the boards and allow the frames to fold up when not being worn.

The Arduglasses use the same ATmega32U4 microcontroller as the Arduboy, and with a few basic controls and a small 100 mAh rechargeable battery onboard, they can technically run anything from the open source handheld’s extensive software library. Of course, technically is the operative word here. While the hardware is capable of playing the games, [Kevin] reports that the OLED displays are too close to the wearer’s eyes to actually focus on them. That said the ability to easily create software for these glasses offers plenty of opportunity for memes, as we see in the video below.

For reasons that are probably obvious, [Kevin] considers the Arduglasses an experiment and isn’t looking to turn them into a commercial product or kit. But if there’s interest, he’s willing to put the design files up on GitHub for anyone who wants to add a pair of Arduino glasses to their cyberpunk wardrobe.

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Dreaming Of A Transparent (PCB) Christmas

[Carl] wanted to put his force sensors on a transparent PCB and had to ask his board vendor for a special sample. Flexible PCBs are available on transparent substrates made of PET, but they are not as common as polyimide boards. As [Carl] found out, these boards are a bit thicker, a bit less flexible, and don’t hold up to very high heat as well as the standard boards. Undeterred, he designed a 3D Christmas tree using the clear boards. The result that you can see in the video below looks pretty good and would have been hard to duplicate with conventional means.

When you build the board it is as a flat spiral, but lifting it in the center allows it to expand into a conical tree shape. The circuit itself is just an LED blinker, but the flexible board is the interesting part.

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Knockoff Kapton Nearly Sinks DIY Flex PCB Project

[TinkersProjects] experimented with making their own flexible PCB for LED modules inside a special fixture, and the end result was at least serviceable despite some problems. It does seem as though the issues can be at least partially blamed on some knockoff Kapton tape, which is what [TinkersProjects] used as a backing material.

Incomplete etching on this DIY flexible PCB, but still salvageable.

The approach was simple: after buying some copper foil and wide Kapton tape, simply stick the foil onto the tape and use the toner transfer method to get a PCB pattern onto the copper. From there, the copper gets etched away in a chemical bath and the process is pretty much like any other DIY PCB. However, this is also where things started to go wonky.

Etching was going well, until [TinkersProjects] noticed that the copper was lifting away from the Kapton tape. Aborting the etching process left a messy board, but it was salvageable. But another problem was discovered during soldering, as the Kapton tape layer deformed from the heat, as if it were a piece of heat shrink. This really shouldn’t happen, and [TinkersProjects] began to suspect that the “Kapton” tape was a knockoff. Switching to known-good tape was an improvement, but the adhesive left a bit to be desired because traces could lift easily. Still, in the end the DIY flexible PCB worked, though the process had mixed results at best.

Flexible PCBs have been the backbone of nifty projects like this self-actuating PoV display, so it’s no surprise that a variety of DIY PCB methods are getting applied to it.

Microstepping A PCB Motor

Over the last 2 years [Carl Bujega] has made a name for himself with his PCB motor designs. His latest adventure is to turn it into a stepper motor by adding position control with microstepping.

The NEMA stepper motors most of us know are synchronous stepper motors, while [Carl]’s design is a permanent magnet design. It uses four coils on the stator, and two permanent magnets on the rotor/dial. By varying the current through each of the four poles with a stepper driver (microstepping), the position of the rotor should theoretically be controllable with good resolution. Unfortunately, this was easier said than done. He achieved position control, but it kept skipping steps in certain positions.

The motor and controller consist of a single flexible PCB, to reduce the layer spacing and increase the coils’ magnetic field strength. However, this created other problems, since the motor shaft didn’t have a solid mounting point, and the PCB flexed as the stator coils were energized. Soldering the controller was also a problem, as the through-hole headers ripped out easily and the PCB bulged while reflowing on a hot plate, in one case even popping off components. [Carl] eventually mounted one of the PCB motors inside a 3D printed frame to rigidly constrain all the motor components, but it still suffered from missed steps. Any suggestions for fixing the problem? Drop them in the comments below.

Like his other PCB motors, the torque is very low, but should be suitable for gauges or clocks. A PCB clock with an integrated motor would be pretty cool to have on the workshop wall.

The TMC2300 stepper driver [Carl] used belongs to the same family of drivers that enable silent stepping for 3D printers. We’ve covered a few of [Carl]’s PCB actuator adventures, from his original design to linear actuators and a flexible POV display.

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Hinge Brings New Meaning To Flexible PCB

It is not a secret that flexible PC boards can bend. But despite the substrate’s flexibility, you can’t really fold them completely over. That bothered [Carl] so he developed a hinge design so that he can fold a board completely in half. You can watch a video showing an example, FlexBox, below.

Normal boards can fold over, but the copper traces can’t tolerate a very tight bend radius. [Carl’s] trick is to make the folding part have no traces at all. Only a small bridge carries traces between the two halves and it is allowed to bend almost like an interconnecting cable.

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Magnets Turn Flexible PCB Into Electric Grasshopper

Just because something doesn’t seem to have an apparent purpose, that doesn’t mean we shouldn’t try making it anyway. As flexible PCBs become cheaper and easier to order from low-scale fab houses, we’re seeing hobbyists experiment with new uses for them such as [Carl Bugeja]’s jumping circuit.

The circuit is based a coil printed on the flexible PCB itself acting as an electromagnet, but unlike other designs which use the same trick, in this one the coil is made to be the static side of an actuator. Attached to the circuit with folding arms is a stack of two permanent magnets, which work as the moving part. Since the magnets make up most of the mass of the circuit, as they’re pushed down and sprung back up, it causes the whole thing to leap around just under one centimeter off the table like a little electric grasshopper.

This is far from [Carl]’s first appearance here on Hackaday, and he’s been clearly busy exploring new uses for flexible PCBs with their properties as electromagnets, from making POV displays with them to small robots that move around through vibration. We’re excited to see what else he can come up with, and you can see this one in action after the break.

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Latest FlexLED Milestone Refines The POV Display

With his FlexLED project, [Carl Bugeja] is trying to perfect a simple and affordable persistence of vision (POV) display capable of generating “holographic” characters in mid-air. Traditionally POV systems spin LEDs rapidly to create the desired illusion, but that means motors, slip rings, and noise. As the name implies, the goal with this project is to do away with all that and replace it with a self-actuating flexible PCB.

The device is able to quickly move the LEDs back and forth quietly and efficiently thanks to a permanent magnet and magnetic coils integrated into the flexible PCB. With no motors or gears, the whole unit is smaller and less complex than other POV displays. As an added bonus, there’s no danger to the operator or the device should a curious user stick their finger into it.

The last time we took a look at this project, [Carl] had entered an earlier single-LED version into the 2019 Hackaday Prize. Competition was tough last year, and unfortunately FlexLED didn’t get selected as a Finalist. But we’re still extremely interested in seeing the project develop, and we imagine so are you.

The recently completed second version of the display features an improved coil design, eight RGB LEDs and a 3D printed base with integrated magnet. With more LEDs onboard, a single display is able to show multiple characters and even rudimentary animations. A large array of these flapping elements promises to be quite a sight.

But before you get too excited, [Carl] does have some bad news. For one, the cost of building them in small quantities is high, which is always tough for a single hacker trying to iterate a design. Worse, some of the LEDs seem to have died on this prototype already. He says it likely has something to do with the stress of flexing back and forth so quickly, which is obviously a bit troubling. He’s looking to get some feedback from the community, and is hoping to address these issues in the next version.

For an interesting look into his flexible PCB actuator projects, check out the interview [Carl] did with us at the 2018 Hackaday Superconference.

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