The design is very simple, I have provided hinge at the back to open up the cover and in the front side I have provided locking system which can be simply pushed to close and lock the lid.

The most important design decision is how to design so that it becomes waterproof. So, as you can see I have provided a layer of rubber coating inside which has a concave groove on it and in the lid cover there is also rubber coating with convex shape which exactly fits in when the lid cover is closed thus making it water resistant. 

Moreover the rubber coating also saves the inside device from any kind of damage caused by vibration if it falls. Point to consider here that the size of the inner layer of the box i.e. the rubber coating exactly coincides with the device size which would be placed inside so that it can hold the device firmly in its place.

As there is a camera in the device so a circular section is cut out and a glass is placed so that the camera can work while inside the waterproof cover.

The lid cover can be closed by simply pushing it downward and it will automatically be locked in the groove provided. The two hooks at the front perfectly fits in the groove and both the hooks are designed with elliptical form for a smooth sliding during closing and opening of the lid.

The lid cover can be opened up by pulling the hooks little outward which will eventually pull out the elliptical locking part out of the groove and it can be opened up. The surface below the elliptical part is little extended so that it helps the user to pull out the hook.