Oct 12

3D Printed Cufflinks


Every once in a while my family makes me socialize with other people. We recently attended a community benefit that required me to wear a tuxedo. It may come as some shock to you, but the reality is that I don’t normally have a lot of cufflinks on hand. While I could certainly go to the mall to get a pair in 15 minutes, I decided to spend the better part of an afternoon making my own.

I recently purchased a 3D printer, and it’s far exceeded my already lofty expectations in terms of its possibilities. It’s Maslow’s Hammer become real, because everything actually is a nail when your hammer has the ability to command matter into existence. Like most tools, there are constraints you need to work within, but spitting out cufflinks felt well within the envelope.

The first step is creating a 3D model of the object you want to print. I use a CAD package called SolidWorks, which is a bit complex but quite powerful once you get the hang of it. I was able to design something I was happy with in about an hour.


The printer creates objects using ABS plastic in one of a few solid colors like White, Black, Red, etc. The printer that I have also can print out support material to prop up parts of the model as needed during the build process. The photo below shows 3 of the cufflinks fresh out of the printer. the leftmost one is the orientation as printed. The middle one shows the support material “raft” on the bottom, and the final one shows the black plastic cufflink after I manually broke the raft off.


You can break away the support material with tools if you are patient and careful, but if you don’t mind waiting a while it’s far easier to dissolve it. I dropped the cufflinks into a heated agitation tank filled with lye and a few hours later the white support material was completely gone.


I was going to wear a black shirt, so I wanted the cufflinks to look silver. I spray painted two coats of Krylon Chrome spraypaint and it looked reasonably well from a distance. The final touch was to paint the bowtie black using some acrylic paint and a tiny brush.

bowtie-paintingIMG_20120923_133227 (400x342) (2)

The printer uses a process called FDM which creates a somewhat rough surface texture that is apparent in the close-up pictures. It’s possible to smooth out the surface by sanding and applying solvents, but I actually wanted a matte finish so the result was good as-is from the printer. At the party someone saw my cufflinks and asked if they were silver – achievement unlocked.

I’m sure I could make literally dozens of dollars selling these on Etsy, but instead I’ve published the design files so anyone can make a pair themselves. Even if you don’t have a 3D printer, there are sites like Shapeways or Ponoko that will print them for you for a fee. The design files can be found on Thingiverse. You can upload the file to Shapeways and print a pair in plastic for about US$7 or they’ll also gladly print them in silver for about US$100. If someone actually does that, I’d love to see some pictures!

May 11

Chocolate & Peanut Butter

chocolatepbIn the opening day Google I/O Keynote, Android announced numerous cool new products. I had the pleasure of introducing our new Movie Rental Service for Android Market, and we also talked about our new Music Beta service as well as the Accessory Development Kit for the first time. Combining devices with cloud services is a Chocolate & Peanut Butter experience – each benefits from the other to create a whole larger than the sum of their parts, so I wanted to try out the ADK and do a project that captures this. My buddy Joe hooked me up with an ADK board a week before I/O so I could play around with the ADK and I did a project that combines the coolness of devices and hardware with the awesome new Music Beta service.

First a little background on the ADK. The board that Google was handing out at I/O is based on Arduino and has a built-in Circuits@Home USB Host shield. The details can be found at the Android Open Accessory page at the Android Developer portal. A library is provided for the Arduino board that allows you to identify your device and very easily detect when an Android Device is connected to it and transfer data.

I already had a box of Sure Electronics LED matrices left over from Maker Faire last year. That plus some ShiftBrite RGB LEDs and the judicious application of a laser beam to build an acrylic enclosure was sufficient to get the basic sign up and running. It sported a two-line display (64×8 pixels each) driven by my LED Matrix Library and a Music Beta by Google logo backlit through a diffuser panel by 6 ShiftBrites.

Then I linked to the Android ADK library and it was literally just a few lines of code to detect a device connection and read some data. The other very cool feature of Android Open Accessory is you can provide a URL in your device description metadata. When a user plugs in their Android Phone, if there isn’t a compatible application for your device the user can follow the link to download the supporting application directly from Android Market. In my case, I needed a simple service application that listened to the Intents the Music App sends when it changes track metadata. Then, the app writes the metadata to the Arduino board. So the end-user experience is seamless – anyone can walk up to the sign and plug in their phone and be up and running in a few seconds.


Once I’ve decompressed from I/O a bit, I’ll publish the source code and CAD files so others can put one of these together. For now here’s a video of the Music Beta Now Playing accessory in action. The fun spectrum analyzer animation is just for effect – it’s not actually analyzing the audio, but maybe some clever person can make that part more real.