Patents can be for several different inventions including, but not limited to machines, apparatus, and compositions of matter, computer software, designs, and much more. An invention can be patented, if, several conditions are met. Under 5 U.S.C. 101. Patentable Inventions are “Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title. The conditions of novelty and non-obvious subject matter are discussed in 35 U.S.C. 102-103.
Your invention must be novel. This means that you are the first to create the invention. Under 35 U.S.C. 102-103 novelty and other hurdles to acquiring patents are described in more detail The claimed invention must not have been patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. The invention must not have been known or used by the public in the United States. A person is not entitled to obtain a patent for something derived from or invented by another person.
The invention must have non-obvious subject matter. 35 U.S.C. 103 describes what non-obvious subject matter is. If the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner, in which, the invention was made. In determining whether, an invention is obvious, the Supreme Court set forth the following considerations: (1) the scope and content of the prior art; (2) the level of ordinary skill in the art; and (3) the number of differences between the prior art and the claimed invention. Graham v. John Deere Company of Kansas City, 383 U.S. 1(1966).
Of course there are exceptions to every rule. There are more guidelines to take into account, as well. However, as long as you are the first inventor of the invention you can patent it. Should you choose to patent your invention or are considering patenting your invention a Patent Attorney should be your first step.