##Simple low cost wireless heart beat monitor with NodeMCU and AD8232.
Much information is provided by Teoma Naccarato and John MacCallum.
For setup details, see instructable at.
NodeMCU code is adpoted from: https://github.com/blakeMilner/real_time_QRS_detection
which implements Pan Tompkin algorithm for filtering.
AD8232 Heart Rate Monitor Hookup Guide https://learn.sparkfun.com/tutorials/ad8232-heart-rate-monitor-hookup-guide