only one dc motor spins

Hi,
OPs servo code;

/*
#include <Servo.h>

Servo servoLeft;  //Define left servo
Servo servoRight;  //Define right servo

*/

void setup() {
  servoLeft.attach(2);  //Set left servo to pin 10
  servoRight.attach(3);  //Set right servo to pin 9
}

void loop (){
 for (pos = 0; pos <= 180; pos += 1) { // goes from 0 degrees to 180 degrees
    // in steps of 1 degree
    servoLeft(pos);              // tell servo to go to position in variable 'pos'
    delay(5000);                       // waits 5ms for the servo to reach the position
    servoRight(pos);
    delay(5000)
    
  }
  for (pos = 180; pos >= 0; pos -= 1) { // goes from 180 degrees to 0 degrees
    servoLeft(pos);              // tell servo to go to position in variable 'pos'
    delay(1);                       // waits 5ms for the servo to reach the position
    servoRight(pos);
    delay(1)
    
  }
}
delay(5000);                       // waits 5ms for the servo to reach the position

Does not wait for 5ms,it waits for 5000ms, or 5s, while it waits, NOTHING is done, the program STOPs.

try

delay(100);

How are you powering the servos.
Can you please post a copy of your servo circuit, in CAD or a picture of a hand drawn circuit in jpg, png?
Thanks.. Tom... :slight_smile: