hm10 ble with metro mini

Using Arduino Microcontrollers
1

I am using the hm10 ble module with the metro mini.
metro mini: Pinouts | Adafruit Metro Mini | Adafruit Learning System
hm10 ble: HM-10 Bluetooth 4 BLE Modules | Martyn Currey

I had it working when I was using an arduino nano. I am curious why the same functional circuit and same code does not work with the metro mini.

I confirmed the hm10 is powered at ~5V I used a voltage divider for the rx and tx using software serial to convert the 5v signal to 3.3v. I am using pin 4 and 5 on the metro mini. I have tried setting the baud rate to a few different values.

The phone app I created is able to connect to the hm10, but the data doesnt flow through (I dont see the print to the monitor from the code).

All of it was working when using the arduino nano. I believe the issue is related to the rx/tx pins and possibly the baud rate but im not sure whats missing.

The code Used on the metro mini (same as arduino nano):

#include <SoftwareSerial.h>

SoftwareSerial mySerial(4,5); // RX, TX  


void setup() {  
  Serial.begin(9600);
  mySerial.begin(9600);
//  mySerial.begin(57600); //required when using the hm-10 with an arduino nano
  mySerial.listen();
}

void loop() {
  // read the value from the sensor:
  if (mySerial.available()){ 
    Serial.print("Received data: ");
    while (mySerial.available())  {
      Serial.write(mySerial.read());
    }
    Serial.println("");
  }
}
2

If the BLE module is outputting at 57600 baud (which it seems you were using with the Nano) and you're now setting the software serial to 9600 baud then that could be a problem.

3

im quite confused.

with the baud rate set to 57600
If I connect the software serial rx (pinn 4) to the tx line on the hm10
and the rx from the hm10 to ground with a 2k resistor inbetween. I get data.

even thought I am getting data that really doesnt seem right. Any ideas why that would work?

4

Well first you said you weren't getting data through, but if you are getting data through that doesn't seem right then my bet would be wrong baud rate. But you'll need to clarify what data you're expecting to see and what data you are actually seeing. It would also be a good idea for you to read this to get a good idea of what sort of details you need to post.

5

When you changed the BAUD rate on your sketch, did you go into AT mode to update it in the HM10?

6