If you're looking to Download Heart Beat Sensor+ on your Chromebook laptop Then read the following guideline.

Heart Beat Sensor is the easiest way to measure your heart rate using your the camera on your iPhone. Simply place your finger on the camera to begin measuring your heart rate and follow the instructions on the screen. Track your pulse right on your phone! You can also add an optional note to each measurement to reference later. Pulse Checker automatically calculates averages for you to see how your heart rate is trending over time. Please make sure that you use your index finger and that the fingertip completely covers the camera lens. Remember to press gently to ensure the most accurate measurement. * NOT INTENDED FOR MEDICAL USE, FOR FITNESS USE ONLY