There are ways to encapsulate, or pot, electronics at home. Probably the most robust would be to start with small container made from a hard plastic, then mostly fill it with epoxy, and hold the electronics about halfway down the container until the epoxy cures. However, cheaper and less time consuming methods would be to completely surround the components with either hot glue or silicone caulking, either normally mounted on a PCB or encasing them separately.
Edit: PeterH beat me to the post.