There are so many flash drives out there it's easy to get your own lost among them. Or maybe, like me, you have several knocking around your bag and get them confused. Well then it's time to make a custom case! It's easy and quick and you can make tons of different designs.

ATTENTION! This is both Instructable AND a challenge. You can be one of five winners of $100 worth of 3D printing credit from the nice folks at 3Dcreationsystems.com. All you have to do is make your own 3D design for a custom flash drive case and share a picture of the design in a comment below.

If you don't know anything about designing in 3D, don't worry! A template for the flash drive is at tinkercad. All you need to do is create a new account (easy), duplicate the template (still easy), and modify it (way easier than it sounds). And if you want to use your own favorite CAD program and make your own case from scratch that's also fine.

OK then, let's get started.

Step 1: Measuring

Break out your ruler or, much better, a set of calipers and measure the dimensions of the flash drive. This drive comes "naked" with an included loop for a keychain so it only has one profile shape. Other flash drives will likely have cases on them. Many of these can be removed with just a little bit of effort.

Here we get a height and width of 4.54 mm and 12.26 mm. This isn't too far off of the USB standards so that's good. It also has a length of 39.11 mm. Since flash drives need at least 12 mm at the end to go into the USB port, that gives us the dimensions 27 mm x 12.25 mm x 4.5 mm. Numbers slightly rounded off there.

Step 2: Making the Template

Going over to tinkercad we can quickly use these dimensions to create the interior shape. So that means we use the same dimensions? Not so fast. 3D printing precision can vary a lot from printer to printer. Because of this I created an inner shape that is 13 mm x 5.5 mm x 30 mm. That's a little extra in the height and width and a lot more in the length. The length gets more because one side will extend past the total shape. This is clearer in the picture.

In this picture, there is the void in the middle and the outer shape that is 4 mm thicker and taller than the inside shape. This gives us a quick open-ended box. Which is close to being done.

The last addition are two small (1 mm) hemispheres. These help to apply pressure to the flash drive to keep it in place.

You can see the resulting template here.

Step 3: Making a Slightly Fancier Template

This next template follows the shape of the flash drive a little closer with a rounded end. The only difference is adding a rounded roof shape to both the outer shape and the void inside.

You can see this template here.

Step 4: Modifying by Adding and Subtracting

Now that we have templates set up we can have more fun. The first image here was made by just adding a couple rings and subtracting a few triangles. With just a bit of work you have a ghost.

You can see the ghost flash drive file here.

The other option is to just subtract a bunch of geometric shapes to form a pattern. Here I just created a series of long box shapes and cut them from the template.

You can see the diamond flash drive file here.

Step 5: Print!

The prototypes for these cases were printed on a Replicator 2, but for the final versions, I sent the files off to 3dcreationsystems.com for a higher quality print in white. The details pop a little better in the higher quality, especially the eyes on the ghost and the fringe at the bottom.

With these in hand you can put your flash drive in. It should be snug enough on its own, but for some extra security put a bit of glue to keep it rock solid.