Stepper Motor Mods Improve CNC Flat Coil Winder

Finding just the right off-the-shelf part to complete a project is a satisfying experience – buy it, bolt it on, get on with business. Things don’t always work out so easily, though, which often requires the even more satisfying experience of modifying an existing part to do the job. Modifying a stepper motor by drilling a hole down its shaft probably qualifies for the satisfying mod of the year award.

That’s what [Russ] did to make needed improvements to his CNC flat-coil winder, which uses a modified delta-style 3D-printer to roll fine magnet wire out onto adhesive paper to form beautiful coils of various sizes and shapes. [Russ] has been tweaking his design since we featured it and coming up with better and better coils. While experimenting, the passive roller at the business end proved to be a liability. The problem was that the contact point lagged behind the center axis of the delta, leading to problems with the G-code. [Russ] figured that a new tool with the contact point at the dead center would help. The downside would be having to actively swivel the tool in concert with the X- and Y-axis movements. The video below shows his mods, which include disassembling the NEMA-17 stepper and drilling out the shaft to pass the coil wire. [Russ] also spent some time reversing the rotor in the frame and provided a small preload spring to keep the coil roller in contact with the paper.

A real-time coil winding session starts at the 21:18 mark, and we’ve got to admit it’s oddly soothing to watch. We’re not sure exactly what [Russ] intends to do with these coils, and by his own admission, neither is he. But it’s still pretty cool to see, and the stepper motor mods are a neat trick to keep in mind.

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Flexible PCBs Make The Fins Of This Robotic Fish

We love a little outside-the-box thinking around here, and anytime we see robots that don’t use wheels and motors to do the moving, we take notice. So when a project touting robotic fish using soft-actuator fins crossed the tip line, we had to take a look.

It turns out that this robofish comes from the fertile mind of [Carl Bugeja], whose PCB motors and flexible actuators have been covered here before. The basic concept of these fish fins is derived from the latter project, which uses coils printed onto both sides of a flexible Kapton substrate. Positioned near a magnet, the actuators bend when a current runs through them. The video below shows two prototype robofish, each with four fins. The first is a scrap of foam with a magnet embedded; the fins did flap but the whole thing just weighed too much. Version two was much lighter and almost worked, but the tether to the driver is just too stiff to allow it to really flex its fins.

It looks like it has promise though, and we’re excited to see where [Carl] take this. Perhaps schools of tiny robofish patrolling for pollution?

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Perf Board Pyrotechnics Courtesy of a High-Voltage Supply

You may have asked yourself at one time or another, “Self, what happens when you pass 100 thousand volts through a printed circuit board?” It’s a good question, and [styropyro] put together this fascinating bit of destructive testing to find out.

Luckily, [styropyro] is well-positioned to explore the high-voltage realm. His YouTube stock-in-trade is lasers, ranging from a ridiculously overpowered diode-laser bazooka to a bottle-busting ruby laser. The latter requires high voltage, of course, and his Frankenstein’s lab yielded the necessary components for this destructive diversion. A chopper drives dual automotive ignition coils to step the voltage up to a respectable 100 kV. The arcs across an air gap are impressive enough, but when applied to a big piece of copper-clad protoboard, the light show is amazing. The arcs take a seemingly different path across the board for each discharge, lighting up the path with an eerie blue glow accompanied by a menacing buzz. Each discharge path may be random, but they all are composed of long stretches across the rows and columns of copper pads that never take the more direct diagonal path. [styropyro]’s explanation of the math governing this behavior is feasible, but really we just liked looking at the pretty and dangerous display. Now if only the board had been populated with components…

No, there’s not much of a hack here, but it’s cool nonetheless. And it’s probably a well-earned distraction from his more serious stuff, like his recent thorough debunking of the “Chinese laser rifle” that was all over the news a while back.

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Friday Hack Chat: Motors Made Out Of PCBs

One of the most amazing technological advances found in this year’s Hackaday Prize is the careful application of copper traces turned into coils. We’ve seen this before for RFID tags and scanners, but we’ve never seen anything like what Carl is doing. He’s building brushless motors on PCBs.

All you need to build a brushless motor is a rotor loaded up with super powerful and very cheap magnets, and a few coils of wire. Now that PCBs are so cheap, the coils of wire are easily taken care of. A 3D printer and some eBay magnets finish off the rest. For this week’s Hack Chat, we’re talking with Carl about PCB motors.

Carl Bugeja is a 23-year old electronics engineer who is trying to design new robotics technology. His PCB Motor design won the Open Hardware Design Challenge and will be going to the Finals of the Hackaday Prize. This open-source PCB motor is a smaller, cheaper, and easier to assemble micro-brushless motor.

[Carl]’s main project, the PCB Motor is a stator that is printed on a 4-layer PCB board. The six stator poles are spiral traces wound in a star configuration. Although these coils produce less torque compared to an iron core stator, the motor is still suitable for high-speed applications. [Carl]’s been working on other PCB motor designs, like the Linear PCB motor which is a monorail on a PCB and the Flexible PCB actuator where the coils of wire are tucked inside Kapton.

During this Hack Chat, we’re going to be discussing:

  • The design and construction of brushless motors
  • How to drive these motors
  • PCB applications beyond standard circuitry
  • Building accessible robotics technology

You are, of course, encouraged to add your own questions to the discussion. You can do that by leaving a comment on the Hack Chat Event Page and we’ll put that in the queue for the Hack Chat discussion.join-hack-chat

Our Hack Chats are live community events on the Hackaday.io Hack Chat group messaging. This week is just like any other, and we’ll be gathering ’round our video terminals at noon, Pacific, on Friday, August 10th. Need a countdown timer? You wouldn’t if we switched to universal metric time.

Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io.

You don’t have to wait until Friday; join whenever you want and you can see what the community is talking about.

Delta Printer Morphs into CNC Flat Coil Winder

Anyone who has ever wound a coil by hand has probably idly wondered “How do they do this with a machine?” at some point in the tedious process. That’s about when your attention wanders and the wire does what physics wants it to do, with the rat’s nest and cursing as a predictable result.

There’s got to be a better way, and [Russ Gries] is on his way to finding it with this proof-of-concept CNC flat coil winder. The video below is a brief overview of what came out of an intensive rapid prototyping session. [Russ] originally thought that moving the coil would be the way to go, but a friend put him onto the idea of using his delta-style 3D-printer to dispense the wire. An attachment somewhat like a drag knife was built, but with a wire feed tube and a metal roller to press the wire down onto an adhesive surface. The wire feed assembly went through a few design iterations before he discovered that a silicone cover was needed for the roller for the wire to properly track, and that the wire spool needed to be fed with as little friction as possible. Fusion 360’s CAM features were used to design the tool paths that describe the coils. It seems quite effective, and watching it lay down neat lines of magnet wire is pretty mesmerizing.

We’ve seen a couple of cylindrical coil winding rigs before, but it looks like this is the first flat coil winder we’ve featured. We can’t help but wonder about the applications. Wireless power transfer comes to mind, as do antennas and coils for RF applications. We also wonder if there are ways to use this to make printed circuit boards. Continue reading “Delta Printer Morphs into CNC Flat Coil Winder”

Mechanisms: Solenoids

Since humans first starting playing with electricity, we’ve proven ourselves pretty clever at finding ways to harness that power and turn it into motion. Electric motors of every type move the world, but they are far from the only way to put electricity into motion. When you want continuous rotation, a motor is the way to go. But for simpler on and off applications, where fine control of position is not critical, a solenoid is more like what you need. These electromagnetic devices are found everywhere and they’re next in our series on useful mechanisms.

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DIY Magnetic Actuator, Illustrated And Demonstrated

Electromagnetic actuators exert small amounts of force, but are simple and definitely have their niche. [SeanHodgins] took a design that’s common in flip-dot displays as well as the lightweight RC aircraft world and decided to make his own version. He does a good job of explaining and demonstrating the basic principles behind how one of these actuators works, although the “robotic” application claimed is less clear.

It’s a small, 3D printed lever with an embedded magnet that flips one way or another depending on the direction of current flowing through a nearby coil. Actuators of this design are capable of fast response and have no moving parts beyond the lever itself, meaning that they can be made very small. He has details on an imgur gallery as well as a video, embedded below.

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