inverted input from AD8232 ECG monitor

[hadwll]

I am developing a project that uses the ESP32 board (devkit3) and the sparkfun AD8232 ECG board. I am using an ecg simulator.

Is there a reason why the QRS wave is looking to be inverted? I have noticed that some other people online have posted ECG results from the same setup but they also look incorrect!

This is an image of my output from arduino serial plotter

ecg1.png (46.07 KiB) Viewed 1394 times

here is an example from github issues post

ecg2.png (86.26 KiB) Viewed 1394 times

here is an example of what it should look like from an arduino board.

ecg3.PNG (79.17 KiB) Viewed 1394 times

the code is as below

Code: Select all

void setup() 
{
// initialize the serial communication:
Serial.begin(9600);
pinMode(14, INPUT); // Setup for leads off detection LO +
pinMode(12, INPUT); // Setup for leads off detection LO -
 
}
 
void loop() {
 
if((digitalRead(10) == 1)||(digitalRead(11) == 1)){
Serial.println('!');
}
else{
// send the value of analog input 0:
Serial.println(analogRead(A0));
}
//Wait for a bit to keep serial data from saturating
delay(1);
}