Two HC-05 modules won't stay paired

Projects Networking, Protocols, and Devices
21

Here is the final code for the slave module, in case anyone is interested. The circuits are as shown in the most recent picture.

#include <SoftwareSerial.h>
SoftwareSerial mySerial(2, 3); // RX, TX
const int button = 8;
int buttonState = 0;
int prevState = 0;

void setup() 
{
  pinMode(button, INPUT_PULLUP); 
  // Set data rate for the serial monitor:
  Serial.begin(9600); 
  delay(5);
  // set the data rate for the SoftwareSerial port to match the UART baud on HC05
  mySerial.begin(38400);
  delay(5);
}
void loop() 
{
    // Reading the button
    buttonState = digitalRead(button);// becomes LOW when button is pushed
    delay(10);
    if (buttonState != prevState) // if button has been pushed or released
    { 
        if(buttonState == LOW)
        {
            mySerial.write('1'); // Sends '1' to the master to turn on LED
            prevState = LOW;
            delay(5); 
        }
        else if (buttonState == HIGH)
        { 
            mySerial.write('0');
            prevState = HIGH;
            delay(5);
        } 
    }     
}