This little thing is simple and fun, and can be used as an instructional design for the introduction of the microcontroller. Gently place your index finger on the sensor and you will see the LED flashing with your heartbeat. After 15 seconds, you can also display your current heart rate on the digital tube. The core part is on the sensor, here is a set of infrared pair tubes. The arteries of the human fingertips are more developed. When the arteries periodically contract and relax with the heart, the blood volume in the blood vessels also changes. Battery Anti-Theft System,Vibration Anti-Theft Function Battery,Gps Anti-Theft Function Battery,Monitoring On Computer And Phone Battery Wolong Electric Group Zhejiang Dengta Power Source Co.,Ltd , https://www.wldtbattery.com