The pulse rate sensor and accelerometer  transmit their data to the ARDUINO UNO microcontroller. Through the Arduino IDE the heart beat is acquired, as well as whether the patient is in resting condition or not.

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  Arduino Uno is a microcontroller board based on the ATmega328P (see datasheet). It has 14 digital input/output pins (of which 6 can be used as PWM outputs), 6 analog inputs, a 16 MHz quartz crystal, a USB connection, a power jack, an ICSP header and a reset button. Its main advantages are,

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• Low cost

• Open-source and extensible hardware

• Easy to learn

• Large support of community

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    Figures below show how the pulse rate sensor, accelerometer and Node-MCU are connected to the board.