OpenCV and Arduino, Help finding X axis coordinate

Projects General Guidance
1

Hello, I am fairly new to programming and was having trouble getting this program to work properly, and thought this might be the place to ask.

My project's idea is to find a person's face from a camera using OpenCV and determine whether the face is on the left or right side of the screen. Python will send the X-axis coordinate to an Arduino through its serial to tell a DC motor to move left or right based on the given number, and align itself with the person's face. (it only moves on the X axis with the help of a guided rail.) I have figured out how to get the coordinates of the face tracker and send them through to the Arduinos serial. As well as making the motor move with different numbers.

my only problem is that python sends the X and the Y coordinate together I only need the X axis coordinate on its own and I am not sure how to get rid of the Y axis coordinate as it interferes with the reading of the numbers for the DC motor on the Arduinos end.
for example, python will send its data something like this
"(340, 367)"
however, I would like it to be read something like this
"340"

if anyone knows how to help in any way that would be greatly appreciated.
thank you

PYTHON CODE

from cvzone.FaceDetectionModule import FaceDetector
import cv2

import serial
import time
arduino = serial.Serial(port='COM5', baudrate=9600, timeout=.1)
time.sleep(2)
def write_read(x):
    arduino.write(bytes(x, 'utf-8'))
    time.sleep(0.05)
    data = arduino.readline()
    return data

cap = cv2.VideoCapture(0)
detector = FaceDetector()

while True:
    success, img = cap.read()
    img, bboxs = detector.findFaces(img)

    if bboxs:
        # bboxInfo - "id","bbox","score","center"
        center = bboxs[0]["center"]
        gamerRage = str(center)
        cv2.circle(img, center, 5, (255,  255), cv2.FILLED)
        print(center)
        arduino.write(gamerRage.encode())


    cv2.imshow("Image", img)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
cap.release()
cv2.destroyAllWindows()

ARDUINO CODE

int myNumber;//serial number

int i = 20;  // motor settup
int R_IS = 5;
int R_EN = 4;
int R_PWM = 3;
int L_IS = 8;
int L_EN = 7;
int L_PWM = 6;



void setup() {
  Serial.begin(9600);//opens comunication
  
  pinMode(LED_BUILTIN, OUTPUT);//led
  Serial.setTimeout(5);//shortens the checking of a number to 5ms(Serial.parseInt)
  pinMode(R_IS, OUTPUT);
 pinMode(R_EN, OUTPUT);
 pinMode(R_PWM, OUTPUT);
 pinMode(L_IS, OUTPUT);
 pinMode(L_EN, OUTPUT);
 pinMode(L_PWM, OUTPUT);
 digitalWrite(R_IS, LOW);
 digitalWrite(L_IS, LOW);
 digitalWrite(R_EN, HIGH);
 digitalWrite(L_EN, HIGH);
  
}


void loop(){
  if (Serial.available()>0) {

   

    myNumber = Serial.parseInt();//this was holding back the code giving the 4 tic delay
    if (myNumber >= 680) {//if less than 680 turn on motor left
      analogWrite(R_PWM, 0);
      analogWrite(L_PWM, i);
    }
      else if (myNumber <= 680) {//if more than 680 turn motor right 
      analogWrite(R_PWM, i);
      analogWrite(L_PWM, 0);
       

   
     
    }
  }
}
2

The numbers are always sent in pairs. You only want the first. Simplest method is to add another Serial.parseInt() once the first one has been read. However, I think you have a second problem as well. If Python sends nothing, parseInt() will return 0 and your code will pan left because 0 is less than 680. Also, if exactly 680 is sent, the code will pan left and there is no reason to test for 680 again in the else.

I would suggest:

myNumber = Serial.parseInt();//this was holding back the code giving the 4 tic delay
if(myNumber > 0){    
    if (myNumber >= 680) {//if less than 680 turn on motor left
      analogWrite(R_PWM, 0);
      analogWrite(L_PWM, i);
    }
      else if (myNumber < 680) {//if more than 680 turn motor right 
      analogWrite(R_PWM, i);
      analogWrite(L_PWM, 0);
    }
    Serial.parseInt();  // Skip over the second coordinate
}

Actually, there is no reason for if(myNumber < 680) at all since everything larger has already been handled.

3

Thank you so much, it works great now.