The Heartbeat Necklace is one of several biometric projects developed by the designer/engineer duo Vanessa Carpenter and Dzl. Vanessa and Dzl make up GeekPhysical, an interactive studio that “create[s] interactive experiences, installations, happenings, or playful rendezvous.” The necklace takes the form of a celtic knotted triangle embedded with a handful of LEDs that twinkle the wearer’s heart rate. It consists of a heart rate monitor (which the user wears) and a receiver housed on the necklace itself. The heart rate monitor sends the signal to the necklace which blinks out the heart rate.
The necklace itself is made from a a custom circuit board which is painted black. The container in the back houses the battery and receiver. Check out their site for more information on their biometric social interaction projects.