In response to your question regarding prior art, I would recommend a search before filing for a patent. The process of pursuing a patent is a time and money consuming endeavor. The patent office expects you to have completed a prior art search before filing for a patent. If your idea is struck down by the patent office, you could end up wasting hundreds, if not thousands, of dollars on filing fees. Conversely, a prior art search can be fairly inexpensive. Depending on the field being searched and how many similar items are uncovered by the search, it could cost as little as $100. A good patent searcher can look at your invention disclosure and give you an estimate of how much the search will cost. A reputable patent searcher is bound to confidentiality and will sign a confidentiality agreement if you choose to execute one. I have been doing prior art searches for 16 years and have helped small inventors and large companies save hundreds of thousands of dollars in filing fees. I'm not a patent attorney and this posting does not constitute legal advice or an actual estimate for services. Hope this helps.