Help troubleshooting HM-10 BLE module connection

Other Hardware General Electronics
1

Hi, I need to connect two HM-10 BLE modules so I am testing out their connections with them both connecting to an arduino UNO each, which is being used as a softserial. I was following a tutorial that does the exact same thing I was trying to do however I couldn't get the same results.

So, what I did is that I did the test using my phone and it worked perfectly. However, once I tried connecting the two modules to each other (one set as master and the other as slave), I could manage to send AT commands to both, the TX and RX pins were working fine and the connections were right however I couldn't get their serials to communicate.

I was wondering if anyone has any experience with something similar, if there is a solution to this issue or if this is just hardware malfunction. Thanks in advance.

Also here's the code I am using:

//  SerialIn_SerialOut_HM-10_01
//
//  Uses hardware serial to talk to the host computer and AltSoftSerial for communication with the bluetooth module
//
//  What ever is entered in the serial monitor is sent to the connected device
//  Anything received from the connected device is copied to the serial monitor
//  Does not send line endings to the HM-10
//
//  Pins
//  BT VCC to Arduino 5V out. 
//  BT GND to GND
//  Arduino D8 (SS RX) - BT TX no need voltage divider 
//  Arduino D9 (SS TX) - BT RX through a voltage divider (5v to 3.3v)
//

#include <AltSoftSerial.h>
AltSoftSerial BTserial; 
// https://www.pjrc.com/teensy/td_libs_AltSoftSerial.html

 
char c=' ';
boolean NL = true;
 
void setup() 
{
    Serial.begin(9600);
    Serial.print("Sketch:   ");   Serial.println(__FILE__);
    Serial.print("Uploaded: ");   Serial.println(__DATE__);
    Serial.println(" ");
 
    BTserial.begin(9600);  
    Serial.println("BTserial started at 9600");
}
 
void loop()
{
    // Read from the Bluetooth module and send to the Arduino Serial Monitor
    if (BTserial.available())
    {
        c = BTserial.read();
        Serial.write(c);
    }
 
 
    // Read from the Serial Monitor and send to the Bluetooth module
    if (Serial.available())
    {
        c = Serial.read();

        // do not send line end characters to the HM-10
        //if (c!=10 & c!=13 ) 
        //{  
             BTserial.write(c);
        //}
 
        // Echo the user input to the main window. 
        // If there is a new line print the ">" character.
        if (NL) { Serial.print("\r\n>");  NL = false; }
        Serial.write(c);
        if (c==10) { NL = true; }
    }
}

The tutorial I was following: https://www.martyncurrey.com/hm-10-bluetooth-4ble-modules/

2

MartynCurrey is the place to go, so now it is down to hardware. Would you show wiring drawings of your devices, good and bad.

3

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