linear motor pcb model railroad track

PCB Linear Motors For Model Trains

Modeling a railroad is hard. Railroads are large, linear pieces of civil engineering. So many modelers are drawn to the smallest scale they can use. Recently a new scale, named T, at 1:450 has been pushing this barrier. But fitting a reliable mechanical drive mechanism and MCU board in a package this size is a challenge. In practice, even more of a problem is getting reliable electrical contact through a metal wheel on metal track (about the worst possible design for a contact).T scale electric locomotive held on a human finger

T always seemed to us a long way out on the bleeding edge. But all that may have changed. In a recent Hackaday.io writeup, author [Martin] describes a PCB technology based linear motor system to externally drive T scale locomotives.

The system uses 4mm planar coils. The underside of the PCB has another coil, so the effective pitch is 2mm. With microstepping, a step of 0.25mm is possible, and trains run smoothly. Current is 3-400mA. Continue reading “PCB Linear Motors For Model Trains”

A row of electromagnetic coils fastened to a metal track

Propel Paper Planes, Bisect Sausages With Electromagnets

Are you still launching paper airplanes using your hands? That’s like a baby’s toy! [Tom Stanton] and his homebrew electromagnetic rail launcher are sure to bring your paper airplane game into the 21st century.

To be fair, these kinds of linear motors can be used for more than just launching paper airplanes, and can already be found in niche industrial applications, mass transportation systems and roller coasters. And, yes, the potential to leverage electromagnetism in the theater of war is also being vigorously explored by many of the world’s superpowers in the form of Gauss rifles and railguns. In the meantime, the video (after the break) proves that it’s entirely possible to build a rudimentary yet effective linear motor in your makerspace, using relatively basic components and fundamental physics.

In short, these launch systems use electromagnetism and well timed electronics to propel a mass of magnetic material down a straight (or sometimes curved) track. Multiple pairs of coils are placed along the track, with each pair subsequently energized by high current as the payload approaches. By using many coils in succession, the mass and its payload can be accelerated to high speed.

While a homemade rail launcher is unlikely to turn the tides of war, [Tom Stanton] explores their lethal potential with an experiment involving high-speed video and supermarket sausages, with gruesome results.

If you’re looking for more, why not check out our our previous coverage on electromagnetic weaponry?

Continue reading “Propel Paper Planes, Bisect Sausages With Electromagnets”

Scratch-Built XY Table Gets The Job Done

Unless you have one large pile of cash to burn through, properly equipping a workshop can take years of burning through little piles of cash. Whether to save a bit of cash or simply for the challenge, [Workshop from Scratch] is doing exactly what his channel name suggests, and his latest project is a XY table. (Video, embedded below.)

A XY table, or cross table, allows a workpiece to be translated in two dimensions, usually on a drill press or milling machine. On a drill press they make repetitive task like drilling a series of holes simpler and quicker. [Workshop from Scratch] built most of the frame with steel flat bar, and the moving parts run on ground steel rods with linear bearings. Lead screws with hand wheels are used to translate the table.

A machine like this requires the opposing plates of each table to be perfectly aligned, which [Workshop from Scratch] achieved by spot welding the matching plates together and drilling them in one operation. He also added T-slot top surface, created by welding wide flat bar on top of narrower flat bar.

With the lack of dials, it doesn’t look like it’s meant for precision work, but we would still be interested to know how repeatable the lead screw positioning is. Regardless, it’s still a useful addition to the shop.

[Workshop from Scratch] is building a rather impressive collection of DIY tools, including a magnetic vise (that he already used with the XY table), magnetic drill press and a hydraulic lift table. We look forward to seeing what’s next on the list. Continue reading “Scratch-Built XY Table Gets The Job Done”

Circular Linear Motor Becomes A Micro Motor Raceway

Over on Hackaday.io we have a lot of people playing around with the possibilities presented by cheap printed circuit boards. Whether that means making a quadcopter from fiberglass or a speaker from etched copper, we’ve seen just about everything. Now, finally, we have a miniature magnetic racetrack. It’s an ant highway, or a linear motor wrapped around into a circle. Or a tiny-scale model railroad. Either way it’s very, very cool.

The ant highway comes from [bobricius], one of the many makers tinkering around with coils and traces. This time he’s built a ten centimeter square board that is, effectively, a linear motor. It’s a three-phase motor made out of PCB coils, with a small magnetic ‘car’ that’s pushed forward. These coils are controlled by an ATtiny10 and a trio of MOSFETs. Wrap that linear motor into a circle and you have a neat little circular track that’s the smallest model car raceway you’ve ever seen.

As with all of [bobricius]’ circuit boards, this one demands a video, and that’s available below. This is an interesting bit of technology, and it’s more than just a raceway for tiny magnetic cars. This could be the beginnings of an analog clock with a digital heart, or the start of the smallest model train layout you’ve ever seen. There’s impressive work being done with PCB motors now that printed circuit boards are so cheap, and we can’t wait to see what’s next.

A quick Hackaday search will reveal [bobricius] as a prolific source of projects whose work we’ve featured multiple times. Favorites include a brushless PCB motor, and an FR4 cell phone.

Continue reading “Circular Linear Motor Becomes A Micro Motor Raceway”

PCBs As Linear Motors

PCBs are exceptionally cheap now, and that means everyone gets to experiment with the careful application of copper traces on a fiberglass substrate. For his Hackaday Prize entry, [Carl] is putting coils on a PCB. What can you do with that? Build a motor, obviously. This isn’t any motor, though: it’s a linear motor. If you’ve ever wanted a maglev train on a PCB, this is the project for you.

This project is a slight extension of [Carl]’s other PCB motor project, the aptly named PCB Motor. For this project, [Carl] whipped up a small, circular PCB with a few very small coils embedded inside. With the addition of a bearing, a few 3D printed parts, and a few magnets, [Carl] was able to create a brushless motor that’s also a PCB. Is it powerful enough to use in a quadcopter? Probably not quite yet.

Like [Carl]’s earlier PCB motor, this linear PCB motor follows the same basic idea. The ‘track’, if you will, is simply a rectangular PCB loaded up with twelve coils, each of them using 5 mil space and trace, adding up to 140 turns. This is bigger than the coils used for the (circular) PCB motor, but that only means it can handle a bit more power.

As for the moving part of this motor, [Carl] is using a 3D printed slider with an N52 neodymium magnet embedded inside. All in all, it’s a simple device, but that’s not getting to the complexity of the drive circuit. We’re looking forward to the updates that will make this motor move, turning this into a great entry for The Hackaday Prize.

Retrotechtacular: A Very British MagLev

When we look back to the 1970s it is often in a light of somehow a time before technology, a time when analogue was still king, motor vehicles had carburettors, and telephones still had rotary dials.

In fact the decade had a keen sense of being on the threshold of an exciting future, one of supersonic air travel, and holidays in space. Some of the ideas that were mainstream in those heady days didn’t make it as far as the 1980s, but wouldn’t look out of place in 2018.

The unlikely setting for todays Retrotechtacular piece is the Bedford Levels, part of the huge area of reclaimed farmland in the east of England known collectively as the Fens. The Old Bedford River and the New Bedford River are two straight parallel artificial waterways that bisect the lower half of the Fens for over 20 miles, and carry the flood waters of the River Ouse towards the sea. They are several hundred years old, but next to the Old Bedford River at their southern end are a few concrete remains of a much newer structure from 1970. They are all that is left of a bold experiment to create Britain’s first full-sized magnetic levitating train, an experiment which succeeded in its aim and demonstrated its train at 170 miles per hour, but was eventually canceled as part of Government budget cuts.

A track consisting of several miles of concrete beams was constructed during 1970 alongside the Old Bedford River, and on it was placed a single prototype train. There was a hangar with a crane and gantry for removing the vehicle from the track, and a selection of support and maintenance vehicles. There was an electrical pick-up alongside the track from which the train could draw its power, and the track had a low level for the hangar before rising to a higher level for most of its length.

After cancellation the track was fairly swiftly demolished, but the train itself survived. It was first moved to Cranfield University as a technology exhibit, before in more recent years being moved to the Railworld exhibit at Peterborough where it can be viewed by the general public. The dream of a British MagLev wasn’t over, but the 1980s Birmingham Airport shuttle was hardly in the same class even if it does hold the honour of being the world’s first commercial MagLev.

We have two videos for you below the break, the first is a Cambridge Archaeology documentary on the system while the second is a contemporary account of its design and construction from Imperial College. We don’t take high-speed MagLevs on our travels in 2018, but they provide a fascinating glimpse of one possible future in which we might have.

It does make one wonder: will the test tracks for Hyperloop transportation break the mold and find mainstream use or will we find ourselves 50 years from now running a Retrotechtacular on abandoned, vacuum tubes?

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A Stepper Motor For Two Dimensions

We’ve all heard linear motors, like those propelling Maglev trains, described as “unrolled” versions of regular electric motors. The analogy is apt and helps to understand how a linear motor works, but it begs the question: what if we could unroll the stator in two dimensions instead of just one?

That’s the idea behind [BetaChecker’s] two-axis stepper motor, which looks like it has a lot of potential for some interesting applications. Build details are sparse, but from what we can gather from the videos and the Hackaday.io post, [BetaChecker] has created a platen of 288 hand-wound copper coils, each of which can be selectively controlled through a large number of L293 H-bridge chips and an Arduino Mega. A variety of sleds, each with neodymium magnets in the base, can be applied to the platen, and depending on how the coils are energized, the sled can move in either dimension. For vertical applications, it looks like some coils are used to hold the sled to the platen while others are used to propel it. There are RGB LEDs inside the bore of each coil, although their function beyond zazzle is unclear.

We’d love more details to gauge where this is going, but with better resolution, something like this could make a great 3D-printer bed. If one-dimensional movement is enough for you, though, check out this linear stepper motor that works on a similar principle.

Continue reading “A Stepper Motor For Two Dimensions”