Problems with mg946r and serial

Projects Programming
1

Hi guys

I control a mg946r servo and various mg996r with serial monitor (or this is my idea xd), and this code with de 996r works it, but with 996r doesnt.

#include <Servo.h>

Servo servoMotor;
int input;

void setup() {
  Serial.begin(9600);
  servoMotor.attach(9);
  servoMotor.write(input);
  Serial.println("Enter an Angle:");
}

void loop() {

  // put your main code here, to run repeatedly:
if (Serial.available() > 0) {
  input = Serial.parseInt();
  if (input > 180 || input < 0) {
    Serial.println ("This isn't valid! Try again!");
    Serial.println("Enter an Angle:");
  }
  else {
    servoMotor.write(input);
    Serial.println(String("You entered: ") + input + String("!"));
    delay (1000);
    Serial.println("Enter an Angle:");
    }}}

The mg946r makes two moves at once (i dont want this) and close serial. After to download java 1.8.0_341 the console said this:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
	at processing.app.Serial.write(Serial.java:254)
	at processing.app.Serial.write(Serial.java:274)
	at processing.app.SerialMonitor.send(SerialMonitor.java:122)
	at processing.app.SerialMonitor.lambda$new$1(SerialMonitor.java:66)
	at javax.swing.JTextField.fireActionPerformed(JTextField.java:508)
	at javax.swing.JTextField.postActionEvent(JTextField.java:721)
	at javax.swing.JTextField$NotifyAction.actionPerformed(JTextField.java:836)
	at javax.swing.SwingUtilities.notifyAction(SwingUtilities.java:1668)
	at javax.swing.JComponent.processKeyBinding(JComponent.java:2882)
	at javax.swing.JComponent.processKeyBindings(JComponent.java:2929)
	at javax.swing.JComponent.processKeyEvent(JComponent.java:2845)
	at java.awt.Component.processEvent(Component.java:6316)
	at java.awt.Container.processEvent(Container.java:2239)
	at java.awt.Component.dispatchEventImpl(Component.java:4889)
	at java.awt.Container.dispatchEventImpl(Container.java:2297)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1954)
	at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:835)
	at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1103)
	at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:974)
	at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:800)
	at java.awt.Component.dispatchEventImpl(Component.java:4760)
	at java.awt.Container.dispatchEventImpl(Container.java:2297)
	at java.awt.Window.dispatchEventImpl(Window.java:2746)
	at java.awt.Component.dispatchEvent(Component.java:4711)
	at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:760)
	at java.awt.EventQueue.access$500(EventQueue.java:97)
	at java.awt.EventQueue$3.run(EventQueue.java:709)
	at java.awt.EventQueue$3.run(EventQueue.java:703)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:84)
	at java.awt.EventQueue$4.run(EventQueue.java:733)
	at java.awt.EventQueue$4.run(EventQueue.java:731)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:74)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:730)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:205)
	at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)
2

Problems with servos almost always arise when you try to use the Arduino 5V pin to power them.

If that is what you are doing, use a separate 5 to 6V power supply, capable of supplying at least 1 Ampere per small servo, or 2.5 A per large servo (MG996R).

Don't forget to connect all the grounds.

3

thanks you so much!

4

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