SparkFun gator:particle Hookup Guide
Here are a few tips for troubleshooting this device.
Heart-Rate and SpO2
Make sure that you are making good contact and have constant pressure on the sensor. For the best results, use your finger tip. A special open-source algorithm is used to determine the Heart-Rate and SpO2 measurements. The algorithm is relatively accurate, but is primarily meant for demonstration purposes and should not be used in critical applications for monitoring a person's health.