HM-10 does not return AT commands

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In short, every time I send an AT command to my HM-10 bluetooth module, it returns nothing.

I don’t know what to do, the connection seems to be right, I don’t have a 2k resistor, so I’m using a level converter in bluetooth RXD, 5v in Vcc and GND-GND

when I hold the button, I get an error message:

Exception in thread "AWT-Eventqueue-0" java.lang.Nullpointerexception at Processing.app.Serial.write(Serial.java:226) at Processing.app.Serial.write(Serial.java:246) at Processing.app.Serialmonitor.send(Serialmonitor.java:121) at Processing.app.Serialmonitor.lambda$new$1(Serialmonitor.java:65) at javax.swing.Abstractbutton.fireActionPerformed(Abstractbutton.java:2022) at javax.swing.Abstractbutton$Handler.actionPerformed(Abstractbutton.java:2348) at javax.swing.Defaultbuttonmodel.fireActionPerformed(Defaultbuttonmodel.java:402) at javax.swing.Defaultbuttonmodel.setPressed(Defaultbuttonmodel.java:259) at javax.swing.plaf.basic.Basicbuttonlistener.mouseReleased(Basicbuttonlistener.java:252) at java.awt.Component.processMouseEvent(Component.java:6539) at javax.swing.Jcomponent.processMouseEvent(Jcomponent.java:3324) at java.awt.Component.processEvent(Component.java:6304) 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.Lightweightdispatcher.retargetMouseEvent(Container.java:4904) at java.awt.Lightweightdispatcher.processMouseEvent(Container.java:4535) at java.awt.Lightweightdispatcher.dispatchEvent(Container.java:4476) at java.awt.Container.dispatchEventImpl(Container.java:2283) 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)

someone could help me?

I’m using that website as a reference:

EDIT: No use null nowhere in the program, it’s a Serial-In, Simple Serial-Out:

void setup() {
  Serial.begin(9600);
  Serial1.begin(9600);
}

void loop() {

  if (Serial.available()) {
    int inByte = Serial.read();
    Serial1.write(inByte);
  }
  if (Serial1.available()) {
    int inByte = Serial1.read();
    Serial.write(inByte);
  }
}

On another PC works just right, already on my error machine, and I do the same thing on both

java arduino bluetooth module

1 answer

1

You say you’re not using null at no time, but that doesn’t mean that you’re not RECEIVING null: if there is an error in reading the serial, it can return null, 0 or something bizarre. Maybe the real problem is in your serial.

Try to use the block try/catch, and treat your mistake. You use it this way:

try{
    /* aqui você insere o trecho que pode dar um erro */
}catch(Exception e){
    /* bloco onde você insere o que deve ocorrer se der um erro */
}

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