Quantity   Component name
1 × Arduino UNO Rev 3 <a target="_blank" rel="noopener noreferrer" href="https://www.dfrobot.com/product-610.html">https://www.dfrobot.com/product-610.html</a>
1 × I/O Expansion Shield for Arduino <a target="_blank" rel="noopener noreferrer" href="http://www.dfrobot.com/product-1009.html">http://www.dfrobot.com/product-1009.html</a>
1 × Heart Rate Sensor <a target="_blank" rel="noopener noreferrer" href="https://www.dfrobot.com/product-1540.html">https://www.dfrobot.com/product-1540.html</a>
1 × ESP8266 WiFi Bee <a target="_blank" rel="noopener noreferrer" href="https://www.dfrobot.com/product-1279.html">https://www.dfrobot.com/product-1279.html</a>