[Solved] Bluetooth message to Arduino Uno doesn't register.

Projects Networking, Protocols, and Devices
1

So I'm using MIT App Inventor 2 to just simply be able to communicate with my Arduino. I have the bluetooth set up right on both ends and the connection is working. However when I use Serial.begin(9600) I can't receive the commands with void serialEvent() or serial.available(). However when I don't use Serial.begin(9600) and my Arduino is connected to my PC I see my commands show up on the serial monitor. I'm new and I'm sure it's something trivial. Thanks!

Here's my extremely short code:

#include <LiquidCrystal.h>
LiquidCrystal lcd(7, 8, 9, 10, 11, 12);

void setup() {
  Serial.begin(9600);
  lcd.begin(16, 2);
  lcd.print("Default");
}

void loop() {
  
}

void serialEvent() {
  Serial.println("serialEvent");
  String input = Serial.readString();
  lcd.clear();
  lcd.print(input);
  Serial.println(input);
}
2

why can't you just use something like the following to receive chars and then store them into an array and just serial print them directly:

void loop(){

    if(Serial.available() > 0){

          char in = Serial.read();
          Serial.println(in);
         
         }


}

just load that in your arduino programme and if you are really receiving bytes then it must show on serial monitor, let go off of the serialEvent to just check even at if its working or not.

3

Tried that before. Only works when I input with the serial monitor. Also I didn't say before that my other bluetooth device can receive the messages that my Arduino sends.

4

Tried that before. Only works when I input with the serial monitor.

then I dont think you are getting anything from the bluetooth, checkout how the tx/rx of the bluetooth are connected to the rx/tx of Arduino on the hardware uart port pins.

5

also ,list a datasheet link to your bluetooth?

6

RXD connected to RX, TXD connected to TX. Also when I disconnect the USB and make it println every second, the TX light stops blinking. This is weird since I was using the same bluetooth thing and arduino yesterday and it was working fine. Also what do you mean by a datasheet of my bluetooth?

7

Also here's a few images of my setup. All the extra wires are form the display I disconnected and am not using.

[Album] imgur.com

I'm very stupid. I had to connect TXD to RX and RXD to TX

8

I'm very stupid. I had to connect TXD to RX and RXD to TX

This is what I told you to check out!

okay so if you want to use the Arduino as a Serial converter please try to use a FT232RL acquiped arduio as its more reliable.