It would be quite simple.
Find a wooden (it must be made of wood, preferably upwards of 1/2" thick) photo frame that is roughly the dimensions of the size of door you want... Then cut a square out of the center of the box using a jig saw on a low speed setting (it's work great, and you'd have nice straight lines). Make sure to make the hole in the box at least 1.5" smaller all the way around than the frame. A cheap hinge can be purchased for 2-3$. Once you cut out the hole in the front of the box either use small pop rivits or 1/4" carriage head bolts to fasten the hinge to the box, then to fasten the hinge to the picture farme, use small 10mm-15mm wood screws (the shortness of the screw is to make sure it dosen't come out on the other side of the hinge, making it look bad and breaking the wood) and carefully screw them through the hinge into the wood. To make a latch to hold the "door" shut, use a strip of velcro, one side fastened to the door, and the other to the box.
For ventilation, cut a hole in the lid of the container, and hot glue some plastic or aluminum window screen to the inside of the hole.
~Royce![]()