Archive for March, 2014

Tutorial: Custom 3D models for KiCad 3D viewer

Posted in Tutorials with tags , , , , , , , , , , , on March 30, 2014 by sethkoberg

One of my favorite features of KiCad is the built in 3D viewer functionality. A lot of your standard components will have a 3D model already assigned to a module, like resistors, capacitors, IC’s, etc., so when you fire up the 3D viewer, you will get a nice approximation as to what your finished, populated PCB will look like. In the image below, all the components came bundled with KiCAD, with the exception of the USB connector. When it comes to modules you’ve download from the web or have created yourself, you may have to create a custom 3D model for that module.

Case in point, my FT230X breakout board uses a Mini USB-B connector which I needed to create a schematic component and PCB module for. Clearly, creating these files didn’t magically generate a 3D model for viewing in the 3D viewer.

Rendered 3D model of my FT230X from KiCads 3Dviewer

Rendered 3D model of my FT230X from KiCads 3Dviewer

Requirements:

  1. 3D modeling software – I used Wings3D for this project to import an OBJ file to edit and export to VRML (*.wrl) for KiCad. You can use any 3D modeling software you like – another good, free one is Blender3D. Whichever modeling software you choose, make sure you know the basics so you can clean up the model you’re modifying. Also, this extra piece of software is needed because the VRML export doesn’t work from FreeCAD, so we need a middle man to take care of that.
  2. CAD software- I’m using FreeCAD to export CAD files to OBJ to modify in Wings3D (you didn’t think I was going to make you actually model anything, did you?). You can use this software to modify the CAD model before exporting to the OBJ format, but since I’m only using it to convert the files, I’m not bothering with learning another piece of software this week.
  3. 3D CAD drawings of your component – You can find these on the manufacturer websites for the part your creating. For this USB connector, searching the part number (67503-1020) on the Molex website will lead you to a link to download 3D CAD Models – they’ve already done the hard work, so why should you.

Downloading CAD Models

For this USB connector, Molex has provided 3 formats for the CAD model: PRO/E, IGES, and STEP. The manufacturer may offer more or fewer formats for the component you’re working with, but a cursory glance at the capabilities of FreeCAD suggests most standard file formats should work. If the manufacturer hasn’t supplied a file format that can be imported into FreeCAD or doesn’t supply 3D CAD models, you may need to find a similar component from a different manufacturer that does for the purpose of this tutorial – you don’t need to use the secondary component in your project and rework your schematic and PCB, as this is just for a 3D rendering, not the final product.

Download the 3D Model file from the manufacturers website and save the file, typically a *.zip, to your computer, then extract the file from the archive to a location that makes sense – I extracted my file to the project directory for the FT230X breakout board.

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Delayed, but not forgotten

Posted in Blog, Gadgets with tags , , , , , , , , , , , , on March 25, 2014 by sethkoberg

Another weekend has passed and I have neglected to post anything; however, this time around, I have been busy working on a little side project that will ultimately interface with the Anemometer. In my last post, I had mentioned the use of KiCad, which I’ve been working on learning to take my mind off of the anemometer for a bit so when I do continue work on it, it will be with a pair of fresher eyes. One of the things I hate is working on a single project and essentially getting burned out before its completion – one of the reasons, I’m sure, I fail to complete many of my projects.

I had decided to move onto learning KiCad so when a project gets to the point of fabrication, I’ll be able to tackle the schematic and PCB design without delaying the process any further than necessary. Eagle cad, a schematic and PCB generating software I’ve used before, is still a superior piece of kit, in my opinion, however, the limitations in the free version was something I wanted to break away from. If I ever do decide to sell anything I design, I would have to purchase a licensed version of Eagle. On top of that, using KiCad will support the open source community by using open source software to develop open source hardware.

So, onto my little side project…

 

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History repeats itself

Posted in Blog with tags , , , , , , , , , , on March 17, 2014 by sethkoberg

As I could have predicted, I have been putting off writing in my blog and working on my projects for a while now. Both have been in the back of my mind, but for one reason or another, I have been neglecting to do anything about them. I have been running into a few problems with the Anemometer, and those things need to be ironed out – issues with the RTC not updating or storing the time correctly, issues with having the anemometer write data to an SD card while simultaneously outputting to the serial monitor – things that I never imagined I would have to take into account. The DS1337 is purportedly hot swappable with the more common DS1307, at least, that is what I figured when comparing registers between the two and the DS1307 worked fine when I was testing code, but when I switched to the DS1337, I started getting the wrong data.

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