Intro to Open Emag

After spending roughly 15$ USD on ingredients and printing this design (with 3$ of PLA plastic), you can own a high quality coil wrapping machine that would have costed many times more in the proprietary world. We all deserve good electromagnets. My reward (eventually) will be to see the photos of other people's successful renditions.

WARNING: This project is JUST THE MECHANICAL apparatus. I do not supply code for controlling the device because there's too many ways to do it. I discuss many options for controlling the servo and motor, but I do not hold your hand and walk you through to finishing the project. Most people reading this are interested in doing something really nerdy and specific, so this modular approach is likely a feature, not a flaw.

This is an OpenScad project that uses a central file (openEmag.scad) that calls upon all of the other files to accumulate a ready-to-print kit that can be assembled (along with a few products) into an electromagnet-wrapping machine. openEmag.stl is the entire kit, rendered such that no support is needed, and the model will fit on printers like the CraftBot (bigger bed than usual). If your bed is too small, you'll have to print the individual parts and most of these parts, I only provide the Scad file. OpenScad files can be converted to STL easily and this allows anyone to edit any part of the design. Most users of this project would like to change the diameter of the wire spool (spoolform.scad) which sets the inner diameter of the electromagnet. Thanks to OpenScad, I don't need a Customizer. Just edit my well-written code! Enjoy the demo video on this page.

Open Emag Controller Project

Something must power the motor while telling the servo to go back and forth slowly. In all cases, the predictable turning rate of the motor means that time can be used as a measure of turns: (time to wrap)=(number of turns)/(rpm) in minutes. There are many ways to operate this machine but I can think of 3 main categories:

• Human controller: You could skip the purchase of a servo and just use your hand, similar to what I do in the demonstration. This would still be much faster and better than manually wrapping without the device. You could even save plastic and comment out the servo mount from the design. Not to hurt your feelings, but this method will yield lower quality results and far less coil consistency than the next two methods.

• Analogue controller: One could make a circuit that produces the control signal for the servo, just making it slowly wave back and forth. There are these things called 'servo testers' which do just this. Along with a switch and a pocket stop watch, fairly accurate electromagnets can be created.

• Digital controller: You can use a computer, like the Raspberry Pi or the Adruino . There are MANY advantages to using a micro-controller, like a variety of wrapping patterns and automatic shut-off when the number of turns has been reached.

Separating the controller project from the mechanical design allows people to choose how much they want to spend and what features they want.

Why electromagnets?

Electromagnets are important in modern life. The average person in modern society relies on electromagnets daily. They have been out for long over a century, and electromagnets are key to all electric motors, all speakers, and all magnetically locking doors, for a small set of examples. There probably are many more inventions that could be created to benefit the world using electromagnets but the public is generally unaware of them. If more people know about this century old idea, people will understand much more about what's going on around them and people could even make new things. It is very likely that the plethora of conveniences from electromagnets is not even close to being realized yet. Electromagnets are the only magnets that can turn off or reverse themselves or change strength on demand. I get excited just thinking about that !!

Why use the machine?

Good electromagnets have hundreds, or thousands of turns. We want to push the limits. No one (in their right mind) wants to count hundreds or thousands of anything. Also, this offers repeatability. You can make 10 electromagnets with 600 turns each, and it would ideally take a little over 30 minutes with this machine (at 200 rpm), that's 3 minutes per electromagnet. Doing that same task by hand?-- well, that's the alternative.