[sdiy] Ensoniq patent, was: distance meter for keyboard, was: Where to get special white keys?

[Rainer Buchty]

On Sun, 1 Mar 2009, cheater cheater wrote:

> OK, I've done a search in online patents databases and couldn't find 
> the patent for ensoniq's hall sensor stuff.. I think I know why.. 
> Patents only last 20 years total (and that's including the single 
> possible renewal you can do)

Just because they are expired doesn't mean they are not listed. There 
are plenty of patents available in the database which are expired.

I remember the one about the gas-sensing device for mine workers from 
the 19th century. It basically consists of a canary bird and a cage.

Definitely expired but in the database.

Rainer