You can get a patent for AN ORIGINAL device, system, or method THAT is new and inventive.
A patent is a temporary monopoly that a government grants to a person that has come up with an original technical invention. Most countries have this system, although the requirements differ slightly from country to country.
Once a patent right has been approved by the government, it will allow you to stop other people or companies from copying the principle on which your idea works.
If your invention meets the general requirements then a patent can usually be granted for the invention in most countries once it has undergone some form of examination by that country's Patent Office. Keep your idea secret until you have filed for some form of protection at your local Patent Office. While you can do it yourself, it's always best to get a registered patent attorney to do this for you, if you can afford to.