When designing the Circuit Playground Express, Ladyada purposely placed the light sensor near the NeoPixel LEDs so that the light from the LED may illuminate a finger and the sensor measure the minute changes in light signalling someone's pulse. While not medically accurate, the project is easy to do and demonstrates several concepts without a bunch of specialized materials.

This tutorial will show you how to set up the Circuit Playground Express and will display the heart rate via a NeoPixel.

Parts