CUPERTINO, Calif. — Apple is expected to unveil new iPads at an event today, as the company tries to drive excitement amid slowing demand for tablet computers. Apple may also announce a new Mac operating system and possibly new Mac computers. Watchers also await a possible launch date for Apple Pay, the company’s new system for using iPhones to make credit and debit card payments at retail stores.

As usual, Apple isn’t disclosing what it plans to reveal at its headquarters in Cupertino, Calif., today. Invites to its event carried the cryptic message, “It’s been way too long.” CEO Tim Cook is expected to preside over the event, which begins at 1 p.m.

New iPadsIt’s been a year since Apple came out with a lighter, thinner full-size model called the iPad Air. Apple is expected to refresh that with a faster processor and possibly a fingerprint ID sensor akin to what’s found on recent iPhones. The sensor would let people use a fingerprint instead of a passcode to unlock the device and authorize Apple Pay purchases.Apple also might offer an iPad with a gold-colored casing, another option already available on iPhones. An updated iPad Mini might be part of the new lineup.Today’s event comes as sales of Apple’s iPads have dropped. Through the first half of this year, Apple had shipped 29.6 million iPads, a 13 percent drop from the same time last year.Apple plans to issue results for the latest quarter on Monday.Apple has been facing competition from cheaper tablets running Google’s Android operating system.

Mac updatesApple has said a new Mac operating system is coming this fall, so there’s been speculation the company will use today’s event to announce more specifics, including timing.The Mac update will be called Yosemite and will include aesthetic changes as well as new functionality, such as the ability to make phone calls with an iPhone nearby and a one-stop search tool for both locally stored documents and online resources.Apple has been releasing Mac updates more frequently, in part to time them with annual changes to the iOS system for iPhones and iPads.

Apple PayApple has already announced its new payments system, Apple Pay, but the iPhone feature wasn’t made available right away. Apple is due to release an iOS 8.1 update that should enable Apple Pay and the ability to send and receive iPhone texts from Macs.With Apple Pay, iPhone 6 and 6 Plus owners will be able to make payments at brick-and-mortar stores by holding their phone near a card reader.The new iPhones have a wireless chip to transmit the information needed to complete the transaction. Owners of older models won’t be able to use Apple Pay, even with the software update.