Sleek smart ring tells you which days to take it easy, which days to go for it

The Oura ceramic ring keeps tabs on your vitals and sleep patterns and gives recommendations on how to maximize your rest and activity. It looks pretty good too.

Could this ring help you sleep better? Olli Keskinen

While most attention in the wearables market has been focused on devices that wrap around our wrists, there are some makers out there that are seeking to put smart technology on our fingers. There are the Ringly and Mota rings that bring notifications to our fingers and the Nod ring, which promises to bring gesture-based controls to lots of our activities.

The newest entry to the smart-ring market -- via a Kickstarter campaign -- is Oura, a waterproof, scratch-proof ceramic ring that measures your vitals and gives recommendations on how to maximize your active periods and improve your sleep.

Oura, created by a team in Finland that includes the person who wrote many of the algorithms for heart-rate monitor giants Polar, uses sensors that measure your body temperature and pulse as well as an accelerometer that keeps tabs on your activity. Through monitoring these vitals -- including the time between heartbeats -- the ring builds a picture of how well you sleep and is able to compare that to how much activity you have during each day. It then uses an algorithm to create suggestions for you on how to improve both.

If, for example, it senses that you slept best on a night when you went for a long casual walk at 7 p.m., but not so good when you started your day with a big run, it'll give you ideas on how to improve things. If you sleep best when you turn in at 10 p.m. but not so good if you stay up till midnight, you'll know about it. Each day it'll give you a "readiness score" that lets you know if it's a good day for challenging yourself, or if it's better to take it a bit easy.

Because the ring doesn't have a display (it works via Bluetooth with an app on your smartphone), it actually looks like an attractive -- if a little big -- piece of jewelry. And, unlike the Ringly models which are made for women, the Oura has a unisex design.

The ring comes with an equally good-looking box that doubles as the charging station. Just drop the ring in when it's running low on a charge (about every three days) and it'll juice up in an hour. As for ring sizing, a company representative told us that they will be sending out sets of plastic ring-fitting kits to backers before shipping so the right size can be ordered.

Early-bird rewards are still available which will get you a ring in either black and white for $199 (about £127, AU$272), which is a savings of $100 off the eventual retail price. The makers are also promising delivery of the rings this November which, if they keep their word, would be an impressive time from launch of the campaign to fulfillment.

Thus far the campaign has made just over a quarter of its $100,000 goal with over a month left.