I haven't tried door hinges yet. I'll try that on the next build. I didn't want to use just strapping, too loose. It didn't feel right. So I used cardboard reinforced with strapping. But I'll play around with a few different designs for the next one.
The hardest part about building this was the symmetry. I would get an idea. make a part. Then I would have to build another, but the mirrored version of it. In the end it took a lot of extra cardboard and hot glue.
Their are little to no gaps in the front. Leaving a semi-sealed interior. Multiple "pockets" allow for storage of pens, phones, or any small items. And the main storage space has a piece of cardboard that can be pushed in to make more room. And it pushes back for a secure hold on the items.
My laptop fits perfectly, along with all my notebooks and books. Which was completely unintentional.
For the base bag I used an my old backpack we got from Costco. I've had the bag since 3rd grade. Which is impressive, given that I'm in college now.
Any questions just ask.