How can i make a thing to push buttons through a waterproof hard-case?(for my camera)?

i see all these waterproof camera cases have buttons that go through to press the buttons on your camera. how do they work. i want to make one to build into my waterproof box so i can hit record and stop. (only 1 button)


am i describing this well?


how do they keep water from getting in when you press the button.How can i make a thing to push buttons through a waterproof hard-case?(for my camera)?
They use little rubber seals, the switches are usually like pistons. They sell little door alarms that use magnets , maybe you could disassemble one and use the workings, I've never taken one apart but I suspect it has a magnetic relay in it. The link is an example, you can find them in Dolar Stores.