A Polar Coordinate CNC Plotter Even Descartes Could Love

Take apart a few old DVD drives, stitch them together with cable ties, add a pen and paper, and you’ve got a simple CNC plotter. They’re quick and easy projects that are fun, but they do tend to be a little on the “plug and chug” side. But a CNC plotter that uses polar coordinates? That takes a little more effort.

The vast majority of CNC projects, from simple two-axis plotters to big CNC routers, all tend to use Cartesian coordinate systems, where points on a plane are described by their distances from an origin point on two perpendicular axes. Everything is nice and square, measurements are straightforward, and the math is easy. [davidatfsg] decided to level up his CNC plotter a bit by choosing a polar coordinate system, with points described as a vector extending a certain distance from the origin at a specified angle. Most of the plotter is built from FischerTechnik parts, with a single linear axis intersecting the center point of a rotary drawing platform. Standard G-code is translated to polar coordinates by a Java applet before being sent to a custom Arduino controller to execute the moves. Check out the video below; it’s pretty mesmerizing to watch, and we can’t help but wonder how a polar 3D-printer would work out.

Have polar coordinates got you stumped? It can be a bit of an adjustment from Cartesian space for sure. It can be worth it, though, showing up in everything from cable plotters to POV fidget spinners and even to color space models.

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Desktop Factory Teaches PLC Programming

How to train young engineers in industrial automation is a thorny issue. Most factories have big things that can do a lot of damage and cost tons of money if the newbie causes a crash. Solution: shrink the factory down to desktop size and let them practice on that.

Luckily for [Vadim], there’s an off-the-shelf solution for miniaturizing factory automation: FischerTechnik industrial training models. The models have motors, conveyors, pneumatic cylinders, and sensors galore, but the controller is not exactly the industry standard programmable logic controller (PLC). [Vadim] set out to remedy this by building an interface between the FischerTechnik models and a Siemens PLC. He went through a couple of revisions of his board, including one using rivets from the sewing store to interface with the FischerTechnic connectors. Eventually, he settled on more robust connectors and came up with a board that lets students delve into PLC programming without killing anyone. The video below shows it going through its paces; we can only imagine where playing with these kits as a kid would have led us.

As great as [Vadim]’s system is for training engineers, we can also see it helpful in getting kids interested in a career in industrial automation. We recently covered a similar effort to show kids big science using LEGO Mindstorms. Both of these can help get STEM kids to see the wider world of technical careers and perhaps steer them into automation. After all, the people who make the robots are probably going to be the last ones obsoleted, right?

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