Smart ring device including sensor

A smart ring device comprising:

• an outer ring;
• an inner ring disposed at least partially on an inside of the outer ring and having a center;
• a printed circuit board disposed between at least the outer ring and the inner ring;
• and
• a first protrusion protruding from one surface of an inner part of the inner ring in a central direction,
• wherein the printed circuit board includes:
• a first light receiving element, comprising light receiving circuitry, disposed at a first position of the outer ring, and a first light emitting element, comprising light emitting circuitry, disposed at a second position of the outer ring and configured to transmit a first signal of a first frequency band, and
• wherein the first protrusion includes:
• a first part protruding from the first light emitting element in a first direction facing the center;
• a second part connected to the first part, and protruding from the first light receiving element in a second direction facing the center;
• and
• a partition wall disposed between at least the first part and the second part, the partition wall extending from a bottom surface of the first protrusion to a top surface of the first protrusion that is radially inward of the bottom surface.