Wrist mounted pulse sensor

This is a very simple wrist mounted heartbeat sensor which detects your pulse using a 24 mm dia piezoelectric buzzer, a drawing pin and an arduino microcontroller. When your heart beats a pulse of blood expands your wrist artery and pushes the drawing pin onto the piezo disc. The electrical pulse produced is read by the arduino analog input and then sent to the serial monitor. A second buzzer can be added to buzz on your pulse . I have also included a second design which incorporates a space for a SeeeduinoXIAO arduino processor and this is powered by USB.

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https://youtu.be/zvSqUMQtTMw

There are also files for making the wrist pulse monitor using a longer case with a 128x32 OLED display showing Beats per minute and a pulse visualisation. A 1M ohm or larger resistor is placed between the A0 analog input and ground pin. This has the action of dumping residual signal to ground to improve the stability o