The Internet of Things just keeps getting bigger …

Sales of wearables technology for fitness, mobile computing and much more are increasing 29 percent this year and will double by 2020 with smart watches overtaking smart wristbands as the most popular devices, according to a new report. But in near future, watch out for smart eyewear. Smart clothes, too. 

Research firm IDC forecasts sales of so-called wearables to hit 101.9 million by the end of the year compared to 79 million in 2015.

Wristbands such as Fitbit remain the most popular, but that trend will change, IDC reports.

Smart watches led by Apple, Moto and others will reach nearly 42 million in sales this year, up from 31.9 million year-over-year.

Wristbands lead as they did a year ago with projected shipments of 51.4 million, up from 39.6 million.

However, within four years, smart watches as they add more capabilities will surge ahead to market dominance with 111.3 million sales compared to wristbands at 60.8 million.

Expected to increase substantially by 2020 will be a new generation of smart eyewear as the technology evolves the original vision of Google Glass and other players.

IDC projects 18.8 million smart eyewear sales in four years, up from some 200,000 today.

So-called smart clothing also will emerge in coming years with sales expected to reach 15.6 million from 2.2 million this year.

Smartphone sales are sagging while these smart wearables continue to grow. Why?

“Unlike the smartphone, which consolidated multiple technologies into one device, the wearables market is a collection of disparate devices,” said Jitesh Ubrani, senior research analyst for IDC Mobile Device Trackers.

“Watches and bands are and always will be popular, but the market will clearly benefit from the emergence of additional form factors, like clothing and eyewear, that will deliver new capabilities and experiences. Eyewear has a clear focus on the enterprise as it stands to complement or replace existing computing devices, particularly for workers in the field or on the factory floor. Meanwhile, clothing will take aim at the consumer, offering the ability to capture new forms of descriptive and prescriptive data.”