Software and Hardware Serial

Projects Programming
1

I trying to communicate the Mega and Nano using HC-05 Bluetooth Module.
I want to have a two-way communication so I am using four(4) HC-05 since bluetooth only communicate in one way. (Correct me if I'm wrong, I'm still learning...)
So what I did is communicate them using Hardware and Software Serial.

NANO(Hardware Serial) -------------> MEGA(Hardware Serial)
NANO(Software Serial) <------------- MEGA(Software Serial)

this is my code for Nano:

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(A0, A1);

void setup() {
  BTSerial.begin(38400);
  Serial.begin(38400);
  pinMode(A5, OUTPUT);
}
int inByte = 0;
int state = 0;
void loop() {
  if ( Serial.available() > 0) {
    inByte = Serial.read();
    Serial.println(inByte);
  }
  switch (inByte) {
    case '1':
      digitalWrite(A5, HIGH);
      delay(750);
      digitalWrite(A5, LOW);
      delay(750);
      break;
    default:
      digitalWrite(A5, LOW);
      BTSerial.listen();
      BTSerial.write('1');
      delay(750);
      BTSerial.write('0');
      delay(750);
      break;
  }
}

This code for Mega:

#include <SoftwareSerial.h>

SoftwareSerial BTSerial(12, 13);
const int buz = 7;

void setup() {
  BTSerial.begin(38400);
  Serial.begin(38400);
  pinMode(buz, INPUT);
  pinMode(11, OUTPUT);
}

int state = 0;
int inByte = 0;

void loop() {
  state = digitalRead(buz);
  if (state == HIGH) {
    Serial.write('1');
    digitalWrite(11, LOW);
    delay(1000);
    Serial.write('0');
  }
  else if (state == LOW) {
    Serial.write('0');
    BTSerial.listen();
    if (BTSerial.available() > 0) {
      inByte = BTSerial.read();
    }
    if (inByte == '1') {
      digitalWrite(11, HIGH);
    }
    if (inByte != '1') {
      digitalWrite(11, LOW);
    }
  }
}

I tried using other Baudrates but still only the Software Serial works.
like 115200 for Hardware Serial and 38400 for Software Serial.

2

Bluetooth is two way, to my knowledge. You're the first one that I hear say this.

Do your baudrates match those of the modules?

Don't use software serial on the mega, you have 3 additional hardware serial ports.

3

sterretje:
Bluetooth is two way, to my knowledge. You're the first one that I hear say this.

Do your baudrates match those of the modules?

Don't use software serial on the mega, you have 3 additional hardware serial ports.

Do you mean I can use only two hc-05 for transmitting ang receiving? If so, may I know how?

Yes, they are the same. When I use 38400 in Nano I also use 38400 for Mega.

So should I use:

Mega(Serial)---->Nano(Serial)
Mega(Serial1)<-----Nano(Software)

4

asymptote:
So should I use:

Mega(Serial)---->Nano(Serial)
Mega(Serial1)<-----Nano(Software)

Yes and

Mega(Serial2)<-----Nano(Software)
Mega(Serial3)<-----Nano(Software)

But Software Serial only works reliable up to (about) 38400 and there should be no interrupts in the background that disturb the SWserial timing. Also you must actively wait when you want to receive with SWSerial.

5

I got it already! Thank you so much! I only used the Serial and two of it