Wrist mounted pulse sensor

thingiverse

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. NANO=============================================================== 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 of the display. The BPM timing routine was borrowed from an example I saw on the NET and uses a link between buzzer 2 on D5 which is an output to D8 set as an input so that the sketch times the period between buzzer 2 pulses and displays as BPM. Power is via USB but can be from another source of 5V. Arduino IDE can monitor and plot the output as a pulsed graph. The project is intended to be educational and fun rather than serious and the wrist must be stationary to get a good display.