Magnets Turn Flexible PCB Into Electric Grasshopper

March 31, 2020 by Erin Pinheiro 6 Comments

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

February 28, 2020 by Tom Nardi 7 Comments

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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Detecting Water Before It’s Too Late

November 14, 2019 by Gerrit Coetzee 25 Comments

[mcu_nerd] is like any engineer, which is why his problem of an occasionally leaky water heater sure looks like a research project with no end in sight. Sure there’s probably a commercial product out there that can be had for half the cost and a few clicks of the mouse, but what’s the point in actually solving the problem?

His log starts with research into detecting low battery voltages. Then it was a quick exploration in designing low-power circuits. When the Flexible PCB contest came along, he realized that there was a chance to design a better electrode, and he ended up winning one of the vouchers; which is where he’s at now.

It’s definitely a work in progress, and if anything it’s just a quick five minute read and an opportunity to commiserate with another wayward soul. We do like his clever use of a tealite candle tin as both the second electrode and case for his water detection circuit. There are also some KiCad files and code.

Tiny Two-Legged PCB Robot

August 19, 2019 by Sharon Lin 3 Comments

YouTuber and electronics engineer [Carl Bugeja] has a knack for finding creative uses for flexible PCBs. For the past year, he has been experimenting with PCB motors, using them on drones, robot fish, and most recently swarm robots. This is his final video in the vibro-bot series, and he’s got his best results to date. (Embedded below.)

He started off with flexible PCB actuators as robotic legs and magnets fitted into 3D-printed shells. The flexible PCB actuators work as inefficient electromagnets, efficient enough to react to a magnet when a current runs through, but not so efficient that they don’t release immediately.

The most recent design uses a rigid 0.6 mm FR4 PCB that acts as the frame to prevent the middle of the robot from bending. The “brain” of the robot is located at its center, which is connected to the flexible PCB actuators. Since the biggest constraint on his past robots was weight, he removed two of the legs to reduce the weight by 20%, resulting in straighter walks. He also added a Bluetooth module to wirelessly control the robot and replaced his old LiPo with a new, lighter battery (28 mAh, 15 C, 420 mA).

His latest video now shows that the robot is able to move forwards, backwards, and side to side. That’s a huge improvement over his previous attempts, which mostly resulted in the robot vibrating in place or flopping around his workbench. It’s not going to fetch you a beer, but it’s really cool.

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FlexLED Is A Unique Take On Persistence Of Vision

July 9, 2019 by Lewin Day 13 Comments

Many hackers have experimented with the persistence of vision effect. Whip around a bunch of LEDs, flash them at just the right times, and it’s possible to make images to appear to hang in the air. There’s plenty of ways to do this, whether by manually shaking the LEDs by hand, spinning them around, or even putting them on your bike wheels. [Carl Bugeja] went a different route, taking advantage of the possibilities created by flex PCBs.

[Carl]’s project goes by the name FlexLED. This aptly describes the build, which, in prototype form, mounts a single LED on the end of a flex PCB. The PCB itself has a pattern of traces creating a coil, which enable it to interact with magnetic fields more strongly. By passing the right current through the coil, the flexible PCB can be made to flap up and down, moving the LED on the end at a rapid rate. By then controlling the flashing of the LED, it’s possible to create a persistence of vision effect.

Currently fitted with only one LED, capable of 3 colors, the visual display of the FlexLED is somewhat limited. However, [Carl] reports the effect is more impressive in person than on camera, and is already working on plans to scale up the project to a multi-LED diplay.

POV technology can do some pretty impressive things – even volumetric displays are possible. If you’re working on something yourself, be sure to let us know. Video after the break.

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Arduboy Goes Thin And Flexible For Portable Gaming

April 18, 2019 by Brian McEvoy 5 Comments

We all have a gaming system in our pocket or purse and some of us are probably reading on it right now. That pocket space is valuable so we have to budget what we keep in there and adding another gaming system is not in the cards, if it takes up too much space. [Kevin Bates] budgeted the smallest bit of pocket real estate for his full-size Arduboy clone, Arduflexboy. It is thin and conforms to his pocket because the custom PCB uses a flexible substrate and he has done away with the traditional tactile buttons.

Won’t a flexible system be hard to play? Yes. [Kevin] said it himself, and while we don’t disagree, a functional Arduboy on a flexible circuit makes up for practicality by being a neat manufacturing demonstration. This falls under the because-I-can category but the thought that went into it is also evident. All the components mount opposite the screen so it looks clean from the front and the components will not be subject to as much flexing and the inputs are in the same place as a traditional Arduboy.

cost = low, practicality = extremely low, customer service problems = high

~[Kevin Bates]

These flexible circuit boards use a polyimide substrate, the same stuff as Kapton tape, and ordering boards is getting cheaper so we can expect to see more of them popping up. Did we mention that we currently have a contest for flexible circuits? We have prizes that will make you sing, just for publishing your flex PCB concept.

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New Contest: Flexible PCBs

March 6, 2019 by Dan Maloney 14 Comments

The now-humble PCB was revolutionary when it came along, and the whole ecosystem that evolved around it has been a game changer in electronic design. But the PCB is just so… flat. Planar. Two-dimensional. As useful as it is, it gets a little dull sometimes.

Here’s your chance to break out of Flatland and explore the third dimension of circuit design with our brand new Flexible PCB Contest.

We’ve teamed up with Digi-Key for this contest. Digi-Key’s generous sponsorship means 60 contest winners will receive free fabrication of three copies of their flexible PCB design, manufactured through the expertise of OSH Park. So now you can get your flex on with wearables, sensors, or whatever else you can think of that needs a flexible PCB.

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