Low cost and efficient ECG measurement system using PIC18F4550 microcontroller

This paper demonstrates a simple, efficient and low cost ECG and heart beat measurement system using PIC18F4550 microcontroller. The design includes LT1028 OP AMP IC based signal conditioning unit. Detected ECG signal inside microcontroller is send to a Lab VIEW based GUI platform with USB CDC protocol and also tested with RS-232 protocol. Signal plotting and heart beat calculation is done inside LabVIEW program. ECG signal can also be viewed from PWM port of PIC18F4550 microcontroller via a low pass filtering stage. The whole design is simulated successfully with Proteus circuit simulator. The ECG signal is extracted in audio format (.WAV) from LabVIEW biomedicai toolkit for ECG simulator keeping 1.2 mV upper voltage limit and -0.4 mV lower voltage limit. The audio file is given as the input to the circuit in Proteus. USB simulation is done with the help of Proteus Virtual USB and Microchip USB CDC driver. RS-232 virtual serial port is created using Eltima virtual serial port software. MPLAB IDE is used as microcontroller program compiler.