I2C prints 0 or 1 instead of string

Projects Networking, Protocols, and Devices
1

I'm trying to print message from HM-10 on my LCD (16x2) by the following code

#include <SoftwareSerial.h>
#include <LCD_I2C.h>

SoftwareSerial HM10(2, 3);

LCD_I2C lcd(0x27, 16, 2);

char appData;  
String inData = "";

bool needUpdateScreen;

void setup()
{
    lcd.begin();
    lcd.backlight();
    Serial.begin(9600);
    HM10.begin(9600);
}

void loop()
{

  HM10.listen();
  while (HM10.available() > 0) { 
    appData = HM10.read();
    inData = String(appData);
    Serial.write(inData.c_str());
    Serial.write(appData);
    needUpdateScreen = true;
  }

  if(needUpdateScreen){
    lcd.clear();
    lcd.print(inData);
    //lcd.print("TEST");
    needUpdateScreen = false;
  }
}

When I print "TEST" it works without any problem. When I print "inData" I see only 1 or 0.
Something wrong with types?
Many thanks!

2

Solved by using

void serialRead() { 
  while (HM10.available()) {
  delay(10);  
  if (HM10.available() >0) {
    char c = HM10.read();
    readString += c;}
  }
}
3

What do you see on serial monitor? Perhaps 1 and 0 is what is being received?

4

In serial monitor I see the whole string.

5

But what is the whole string?

1 Like
6

I send "MM1" or "MM0" from my ios app. Now, with the serialRead function I can print the whole message. The strange thing was that serial was printing whole message even without "serialRead" function.

7

What function is that? I don't see it in your code. If you meant to say Serial.read(), why do you think that would be needed?

8

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