ZS-040 (HC-05) blueetooth module Arduino Mega

Question

I followed this tutorial http://www.martyncurrey.com/using-an-arduino-mega-with-a-hc-05-zs-040-at-mode/ and it seems that the AT mode is on. (the LED is blinking like it's supposed)

I connected my pins like this:

BT VCC to Arduino 5V out. Disconnect before running the sketch

BT GND to Arduino GND

BT RX (through a voltage divider) to Arduino TX1 (pin 18)

BT TX to Arduino RX1 (no need voltage divider) (pin 19)

This is the code I run: (from the tutorial)

// Basic Bluetooth test sketch 5a for the Arduino Mega. 
// AT mode using button switch
// HC-05 with EN pin and button switch
//
// Uses serial with the host computer and serial1 for communication with the Bluetooth module
//
// Pins
// BT VCC to Arduino 5V out. Disconnect before running the sketch
// BT GND to Arduino GND
// BT RX (through a voltage divider) to Arduino TX1 (pin 18)
// BT TX to Arduino RX1 (no need voltage divider) (pin 19)
//
// When a command is entered in to the serial monitor on the computer 
// the Arduino will relay it to the Bluetooth module and display the result.
//
char serialByte = '0';
const byte LEDPIN = 13; 
void setup() 
{
 pinMode(LEDPIN, OUTPUT);
 // communication with the host computer
 Serial.begin(9600); 
 Serial.println("Do not power the BT module");
 Serial.println(" ");
 Serial.println("On the BT module, press the button switch (keep pressed, and at the same time power the BT module");
 Serial.println("The LED on the BT module should now flash on/off every 2 seconds");
 Serial.println("Can now release the button switch on the BT module");
 Serial.println(" ");
 Serial.println("After entering AT mode, type 1 and hit send");
 Serial.println(" ");
 // wait for the user to type "1" in the serial monitor
 while (serialByte !='1')
 {
 if ( Serial1.available() ) { serialByte = Serial1.read(); }
 } 
 // communication with the BT module on serial1
 Serial1.begin(38400);
 // LED to show we have started the serial channels
 digitalWrite(LEDPIN, HIGH); 
 Serial.println(" ");
 Serial.println("AT mode.");
 Serial.println("Remember to to set Both NL & CR in the serial monitor.");
 Serial.println("The HC-05 accepts commands in both upper case and lower case");
 Serial.println(" "); 
}
void loop() 
{
 // listen for communication from the BT module and then write it to the serial monitor
 if ( Serial1.available() ) { Serial.write( Serial1.read() ); }
 // listen for user input and send it to the HC-05
 if ( Serial.available() ) { Serial1.write( Serial.read() ); }
}

I want to mention that the baud rate is set to 9600 and Both NL & CR is also set.

The problem is when I insert 1 in the Serial Monitor and nothing happens. How can I solve this problem?

Answer 1

Solution

Connection:

• Bluetooth RXD to Arduino Mega pin 11
• Bluetooth TXD to Arduino Mega pin 10
• Bluetooth VCC to Arduino Mega 5V
• Bluetooth GND to Arduino Mega GND

I used this code:

#include <SoftwareSerial.h>
#define RxD 10
#define TxD 11
SoftwareSerial BTSerial(RxD, TxD);
void setup(){
 // replace BAUDRATE as suggested
 BTSerial.begin(BAUDRATE);
 Serial.begin(9600);
 BTSerial.print("AT\r\n");
}
void loop(){
 if (BTSerial.available())
 Serial.write(BTSerial.read());
 if (Serial.available())
 BTSerial.write(Serial.read());
}

after setting AT mode as described in the tutorial above.

I tried running the code with BAUDRATE starting from 9600 to 460800: