Magnet-on-fridge

Christmas is almost upon us, so here’s a great way to create an (almost) entirely 3d printed Christmas present for other humans.

What you’ll need:
Strong magnets. I’m using some rare earth magnets I bought from eBay. I’ve chosen 10x2mm cylindrical ones, but rectangular would do just fine, you’d just have to modify the frame to accomodate.
A sound bite. I’ve chosen snippets of songs that are significant to the people I’m giving these to, but you could choose a phrase that you speak or maybe the sound of something else entirely (A Santa’s “Ho ho ho” or “You’re on the Naughty List!” for example). I’ve used a snippet from John Denver’s song “Annie’s Song”
– A 3d modeling program. I’m using 3DS Max but Blender would be fine, or any program that can create a ‘lathed’ part from a shape.
Audio editing program. I’m using Audacity which is an awesome program. (http://audacity.sourceforge.net/)
– Adobe Illustrator, or another program to convert the screenshot of the soundbite into a vector shape.
The model of the frame. You can make your own, but here’s the one I made to get you started: http://repables.com/r/440
– A 3D printer. While this should be obvious from the title, I suppose I should actually list it here.
Colored filament. I recommend black for the frame itself, then something interesting for the soundbite print. I’m using Premium Bronze PLA and Premium Black ABS from our store (if you’re in Australia check it out: https://www.doodaddoes.com/product-category/printing-filament/) I’ll change the soundbite color for each print I do, but the frame will remain black for every one.

Step 1. Extracting the Audio

Select Audio. Using Audacity (or other audio editor) open the audio file you’d like to use, or record your own.
Trim the audio down to just the part you want to output. Here I’ve chosen just one verse in the song.

Audacity-interface

Zoom and crop this section so that it fills as much of the screen as you can, then take a screenshot. The larger the screenshot is, the higher quality your final output will be.

If you need to, open the screenshot and edit out everything but the waveform.

Annies-Song-John-Denver

Step 2. Converting Audio to Vector

Edit screenshot. Open your screenshot of the audio file in Adobe Illustrator, and we’ll be using the Live Trace feature to convert this screenshot to a vector.

Illustrator-Live-Trace

Live Trace. Copy my settings as a decent starting point, and don’t forget to select ‘Ignore White’. Click ‘Trace’ then choose ‘Expand’ to convert this to a full vector shape (I don’t believe this last step is necessary with later versions of Illustrator)

Scale. You’ll want to now scale the vector down to 134mm wide to fit inside the frame I’ve provided. If you’ve modeled your own frame, make this width whatever is necessary for your frame.

Close-up-of-live-trace

Close up of the vectorized waveform.

Cut Waveform. Since we’ll be ‘lathing’ this waveform, we actually want to split it in half. I created a rectangle and used the Pathfinder tool ‘Minus Front’ to cut the rectangle from the waveform and leave half the waveform.

waveform-and-rectangle

Waveform-halved

Export this shape to a format that can be opened by your 3D modeling package. I saved mine as an old version 8 .ai format since 3DS Max opens this fine.

Step 3. Convert Waveform to 3D Shape.

Open the shape within your 3D program, double check that the dimensions are still correct.

Scale peak height. At this point I recommend actually scaling the half waveform in the direction of the peaks by 200 – 300%. This will give a nicer scale to the final print. The amount will depend on the length of the soundbyte you chose.

Lathe. Choose the Lathe tool and set it to 180º so that it produces a shape like this. This will allow it to sit flush within the frame on the card stock you’ll add later.

3d-Waveform

Export as an .stl file then open with your 3D printer software / Slicer of choice. I’m using Repetier Host and slicing with Cura.

Step 4. Print!

Which Filament? I chose the Premium Bronze PLA since it was a nice subtle color and seemed somehow more like John Denver than say hot pink or purple… The frame was printed from Premium Black ABS.

Bad example. Watch your retraction values or you’ll end up with a stringy mess like this

stringy print

Waveform Print. If all goes well, here’s your final waveform.

waveform-print

Print Frame. Print the frame as well, here’s the link: http://repables.com/r/440

And here’s your printed frame ready for magnet installation.

frame-alone

Step 5. Install Magnets and Card.

Magnets. I glued the magnets in place using a generous amount of super glue. Don’t be shy now, put plenty in there, you don’t want your present to fall off the fridge do you?

installing-magnet

Prepare Card. Cut some card at 134mm x 83mm (if you’ve used the frame I made) lay that in place. We used 3 pieces of card for the frame; a background color, a decorative frame, and a white piece so that the lyrics were more visible.

Write Lyrics. Write your lyrics / soundbite words on the white card.

lyrics-written

Glue the backing card, the frame and the white pieces together.

cards-glued

Glue some more. Glue them to the inside of the frame.

glue-card-in-place

Step 6. Install Soundbite.

Trim and glue. You might need to trim or sand the ends of the soundbite to fit in place, I had to. Once you have a nice snug fit, spread a thin quantity of superglue on the back and position it on the card. Be careful this is a one shot deal, this superglue will leave some nasty looking dried glue spots if you move it once it’s touched the card. Get the position right and don’t move it!

Completed-frame

Magnet-on-fridge

Celebrate. Congratulations, you now have a kickass present ready to give to all your friends / family / workmates!

If you made something using this, leave a comment below and let me know!

Merry Christmahanukwanza from Down Under!