Intro-- what is this instructable? Given the schematic for a simple circuit, make it a real circuit with the base components, some conductive thread, and a 3D printer. No solder, no etching chemicals, no sending away for anything.

This Instructable is to serve as the how-to guide for a 3D-printed electronic circuit library implemented in OpenSCAD, 3D-PCB.  I recreate the full replication process of a simple analog circuit of a blinking LED made from a few transistors, capacitors, and resistors, a single LED, and a AAA battery. I will review how to import the library, and use it to place components in OpenSCAD in a grid, and teach you the basic wrapping techniques for all the included features.

Also included is a more useful example of an LED flashlight.

What do you need? The code base was developed for use by the MakerBot Replicator. Besides the basic electronic components, you will also need conductive thread. I have tried several types of conductive thread, and the best so far (by a wide margin) can be found here.

I have also found it useful to have fine point tweezers and small scissors, to aid in the wrapping and placing of components.

Links: -- www.carrythewhat.com
 -  Library for 3D-PCB
 -  Example printed electronic -- the Cutaway LED Flashlight
 -  3D-PCB Github if you would like to support the project directly
 -  Or visit our etsy shop for other info and to support indirectly

Why? We are entering an age where physical goods increasingly have a digital representation (eg www.thingiverse.com) -- and the means production of such goods are increasingly accessible (eg reprap, makerbot, etc..).  The success of Open Source Software speaks for itself. Open Source Hardware has also seen many achievements in conventional firms (eg with arduino). But future success might lie in distributed manufacturing.

While the data can be ubiquitous and free, the machines are not, and there will always be some material cost in replicating physical goods. To those without, we want to provide access to the fantastic creations these machines are capable of. To the developers of these creations, we hope to provide a valuable user base. And the economic activity generated will drive extra resources into the technologies that power it.

At CarryTheWhat? Replications, we are acting as a case study for the independent, distributed manufacturing of physical open source goods, and there are a number of other makers doing similar things.

The goal of this project in particular is to increase the scope of what can be replicated on a commodity machine. Better solutions some day might be sort of conductive putty or ink, or even a printable conductive plastic or semi-conductor material. But for now, you can print basic electronics using a plastic PCB and conductive thread. So give it a try!

Step 1: Constructing the Circuit

Component layout:  You have a circuit diagram, like the conceptual schematic attached.  The library currently supports the following features: battery holder (AA, AAA, and coin cell), capacitor, resistor, transistor, 1xLED, 2xLED, base board, peg (and cap, for wrapping and holding things together), an SPST slide switch, and a trace hop (for intersecting threads). This example is of a simple analog transistor circuit which causes an LED to blink.

Unfortunately, there is not yet a way to automatically place the components, so you will place each component manually. Spend a few minutes analyzing the circuit, and think about how to arrange it into a grid. I have found the grid layout the easiest for placement and wrapping, but it's by no means the only possibility!

I recommend you sketch out the circuit by hand, roughly how you intend to place them (orientation and relative locations). Also, it might be a good idea to test the circuit with the components you have on a conventional breadboard.

If you prefer Blender or SketchUp, then you can import each component separately (STL files), and place them manually. If you do this, make sure you maintain the orientation so that they will print nicely.

If you are building the circuit in OpenSCAD, download the library file '3D-PCB.scad' via thingiverse or github, and put it in the same folder as your project.  You will also need to do the same for the MCAD library. At the top of your .scad file, import the library, along with the MCAD dependencies (with the paths appropriately altered if necessary):
use <MCAD/regular_shapes.scad>;
use <MCAD/shapes.scad>;
include <3D-PCB.scad>;

Each component in the library has a standardized spacing: the pegs that make up a component are a set distance from that component's center. This value can be accessed by a call to 'get_component_distance()'. If you arrange your components in rows and columns like the example, the distance between the rows and columns should be 2 times this distance. Then if components are placed next to each other on this grid, they can share a peg. Do this where possible, and you will minimize the number of threads you need to wrap.  The caps that go over the pegs will hold your components to a snug connection.

Place your components with calls to the library, along with translate and rotate about z, with as many components sharing pegs as possible.  Tip: OpenSCAD has two rendering options: a quick render and a full render. I suggest using 'quick render' (F5) to preview while placing components. But do not try to rotate or move the rendered 3D model, this only works well after a 'full render' (F6) which in this example took around 10 minutes!

When you are finished, render and export the STL circuit.
Brilliant idea, I like the way you made those easy-to-use wire-crossing pegs with the ones that allow one wire to go under another without contact. I'll be even more impressed if you or someone else can make a parametric inductor-winding guide part for this. <br>Have you thought of including any blocks that might allow through-hole IC's to be placed on one of these boards? Forgive me if there is already something like that, I don't have time to look through your library yet.
This is one of the coolest projects Ive seen, and def something cool to help kids get into electronics. super cool.
Very nice. This is the way to go for 3d-printing. Share designs. <br>I can recommend replacing the LED driver circuit with a Joulethief circuit (http://en.wikipedia.org/wiki/Joule_thief). It is smaller, more reliable, your batteries will last longer and you can easily add LEDS in parallel for more light. <br>The necessary parts can be retrieved from a broken CFL (low power fluorescent lamp).
Hey -- Thanks so much! That's a good idea, definitely on my list of things next to implement. <br> <br>What do you suggest I do about the coil? I know I could scavenge the parts, but I would rather it be maximally printed &amp; precisely reproducible, using similar techniques.
This is a very well-written walkthrough, and the pictures make it easy to follow the process from start to finish. <br> <br>Cool technology, keep up the good work!
This is great if you have access to a 3D printer and want to fiddle with non-insulated, simple circuits... I am curious what you would do with an IC chip or anything with more than three pins... I guess I will stick with wire wrap tech for the more complicated stuff... it has worked wonderfully for several decades,,,
That's a very good question, a 555 timer 8 pin IC is next on my project list -- I have a few ideas for how to implement it. <br> <br>I hear that wire wrap does work very well, but I believe it still requires some specialized, expensive equipment. I'm hoping to do as much as possible with just one machine (the whole structure, plus the circuit).
Well... a simple wire wrap tool averages about $40USD (low$25 high $60) and the sockets range from $1.50 (8 pin) to $10 (28 pin)... this is a LOT less than the $500 low end 3D printer.... I realize that the printer can do other things and will return on it's investment, however I am concerned about the scalability for circuits... the connectors in your project are pretty large, larger than many of the components, placement becomes an issue as well as tight design tolerances for more complex components. There is also the lack of insulation for the conductive thread which may preclude complex circuits that have connections going over one another. none of which are a problem for wire wrap.<br><br>Like I said before, this was a very cool and inspired use of 3D printing but I think it will only be practical for simple circuits at large scales. now if there were only a way to easily embed metal pins in a 3D printed project... it might also be useful for custom shaped boards using wire wrap...
Having no access to a 3d printer myself at the moment (I'm working on scrounging the parts for one from the scrap heap) I have no way to test this. However, I have in the past repaired circuit boards with glue and a conductive pen. This makes me wonder if it might be possible to use one of the drawing heads commonly available for the various models of 3d printer and some variety of conductive pen, and if the ink would be capable of holding up to having another layer of plastic printed over the top... Probably not as cheap as the wire is, but it might lend itself more easily to more confined spaces.
Great idea! Well different from other circuit printing techniques. I can be useful to explain electric concepts at school
Wondering why you used conductive thread and not stranded wire?
I've tried many materials to run the traces.. from basic wires to conductive tapes and glue. So far, this type of thread has had the best combination of characteristics (inexpensive, easy to deal with, low resistance, durability, re-usability, flexibility, etc) -- some of the components involve small knots, threaded through holes etc. While I'm always looking for another material that might be better, this is the best I've found so far.
Old Fart Speaking: When I was a kid, access to printed circuits at home was a real doozey, so my solution at the time was to use &quot;bread board (more like vero-board)&quot;, and just to be that little bit confusing to others, I used to thread it up with single strands from twisted wire. At a glance, the wires were invisible.
I am absolutely thrilled about this technology. Bringing it back into the spotlight by fusing it with 3d print technology is genius. <br> <br>Maybe you could integrate it with KiCAD. It's open source.
Thanks so much!! It's implemented in OpenSCAD right now, which is also open source. A future project is some implementation to generate the OpenSCAD from traditional PCB files --- KiCAD might be the right choice! Thanks for the tip!

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Bio: I'm here to share with the world what the makers can make --- www.carrythewhat.com
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