We have implemented the circuit in veroboard. This system
can work together with laptop and smartphone or individually
by using only smartphone or laptop. In figure 7 both laptop and
smartphone is used. The Laptop has Intel Celeron B820 (1.7
GHz) processor and 2GB ram running on windows 8.1 OS. In
laptop data of the ECG signal is received by USB cable which
is connected to Arduino Uno. In Android phone it is received
by Bluetooth module. We have saved the data of ECG signal in
text file using the software. For analysis, MATLAB R2014a is
used. ECG data stored by the software is imported in
MATLAB. The ECG signal was taken from a boy of 23 years
old in LEAD I. Figure 8 shows the ECG signal without
filtering. It contains noise and power line interference (50 Hz).