Meet the Ear-O-Smart: a smart earring that can monitor your heart rate, calories, and activity level. It uses Bluetooth to connect to your smartphone. The wearable relies on the PPG technology to monitor pulse through blood flow in the skin. Its battery is good for 8+ hours. Buyers do have the option to pick up a DIY kit to customize their earring. The developers are also offering a learner’s kit. Ear-O-Smart is on Kickstarter right now.