Gently lapping waves let me know I’m doing well. A birdcall in the distance is primo, but rare, and my excitement at hearing it usually causes a rush of wind to flood my ears. These sounds are the feedback that you hear when you train your mind to focus and be calm using Muse by InteraXon. Muse ($299) is a headband that monitors the electrical activity of your brain, and pairs with a mobile app to coach you through mind exercises. While the technology behind an electroencephalography (EEG) machine may sound ridiculously complicated, Muse and its app, Muse Calm, make the experience of using one remarkably easy.