There are lots of other word pairs with an -s- and -c- (practise/practice, advise/advice) that are differentiated by the fact that one is a verb (the -s- one) and one a noun (the -c- one). These two have become slightly more separated and slightly less confused, I feel (but maybe you’ve found differently).

To devise is a verb meaning to plan or invent something (usually something such as a process, procedure or mechanism that is quite complicated). “He devised a route to get from Manchester to Birmingham, not using any motorways”, “The clockmaker devised a mechanism for making a watch show the time in 15 different time zones”.

A device is a noun meaning a piece of mechanical or electronic equipment made for a particular purpose (“He constructed a device for making American recipes using English measuring instruments”), or a plan, trick or scheme (and, by extension, a form of words that’s intended to produce a particular effect: “She used a metaphorical device to explain quantum mechanics in her astounding poem”).

So, you could, indeed, devise a device, but I don’t think you’d want to, simply because of the cumbersome repetition (just like you don’t practise practices!).

You can find more troublesome pairs here and the index to them all so far is here.