ef37a wrote:I had read that if you have a good idea for a gizmo and publish the details in a decently widely read place such as SOS it is "in the public domain" and could not be patented?
I think the whole thing is quite complicated and, as I mentioned earlier, subject to legal interpretation... But as Drew says, patents apply to the physical implementation of the idea, not the idea itself. You have to show that it can be made to work, and how.
And that's why it is often argued that it's better not to apply for patents, because by doing so you educate your competitors about how your innovative product works, and they can then find a way to circumvent your patent -- like by using piezo transducers in the reverb tank. Instead, just make the thing and hope you establish a market and make money from large sales quickly, before the competition catch on and do their own version.
But as you say, if a product is revealed in detail in public it is difficult then subsequently to get a patent granted, and just as hard to prevent a competitor from making something very similar.