› added 5 years ago

79

TIL smartwatches measures blood preassure by emitting light to the skin and reading how much light is reflected back; as the heart pumps blood, it causes a variation in blood volume on the skin and can be detected by change in light absorption, a not-so-new technology called photoplethysmogram.

Read more wikipedia.org

via reddit.com

W76QN TIL in 1882 James Williams of Fredonia, Texas patented a mousetrap “incorporating a handgun”
R71dw TIL the production budget of the first season of "It's Always Sunny in Philadelphia" was so low, the cast shot the opening credits sequence using a digital camera themselves while driving around Philadelphia one night. Charlie Day called it the "cheapest credits ever."
VaaZ TIL 10 years later, Twitter still isn’t close to making money
a8MlZ TIL Kassandra in Greek mythology was a Trojan priestess dedicated and cursed by god Apollo to utter true prophecies but never to be believed. Her name is used as a rhetorical device to indicate a person whose accurate prophecies, generally of impending disaster, are not believed by anyone.
w9P6 TIL that the film ‘The Wolf of Wallstreet’ was allegedly financed by corrupt Malaysian government money, according to US Justice Department lawsuit