To document your "claims", i.e. the original idea that you believe to be unique, and, therefore, yours, could be simply to reduce your specific idea to writing and drawing form, put it in an envelope and send it to yourself, or someone else, via certified mail, requiring a signature. That will show that you invented and documented the idea before the data on the envelope, and, so long as it remains unopened, verifies your original work.

You'd be well-advised to research the "prior art" quite thoroughly before doing this, as it also serves to prove that you didn't invent this before the date on which you documented and mailed it.

This scheme is not perfect but has been mentioned repeatedly as a way of ensuring that your invention is properly dated. In countries where date of filing is the determining factor, this doesn't work at all.

RE