This instructable will show you an inexpensive and easy way to make a custom case for carrying a GoPro Hero camera and equipment, but the idea could be applied to many other things. I have a bad habit of just throwing everything into one bag, but since the lens on my new Eye of Mine flat lens underwater housing is prone to scratches I decided it was time to get organized.

I was going to buy a hard case (I've heard of people buying things like cheap handgun carriers), or re-purposing an empty drill case, but the GoPro is already somewhat durable so I really wanted this more for organization than protection. Here were my goals:
1) Small, comfortable, and convenient to carry around and travel with
2) Protect lenses and other equipment
3) Keep all of my goodies well-organized
4) Doesn't say "there's something expensive in this bag"

Step 1: Collect Materials and Supplies

To duplicate this you will need the following:
1) Bag, case, or box in need of re-purposing (thanks to my uncle for a cool retro leather bag)
2) Block of foam, you choose the hardness (I had some lying around, but a craft store will usually have this)
3) X-acto knife or similar cutting tool
4) Marker to draw out your plan

Step 2: Lay Out a Plan

After you've found your bag and collected your materials, cut the foam to fit the bag. I wanted to be able to have all parts with me in case I needed them, but I really wanted fast access to things I might need quickly (the camera, extra batteries, waterproof door). With an idea in mind, lay each piece out and draw an outline.

Step 3: Cut the Foam

Once you have a plan (here's your last chance to measure twice, so you only cut once), get down to business. It's a good idea to pause every few minutes and make sure things are coming together the way you want them to.

Step 4: Test Fit and Finished!

Once you put the final touches on the foam that's all there is to it. I found that I wanted a little extra space for the buttons and other mount parts that I didn't take into account initially (I decided that I wanted to have the option to store both housings in either location).