Help to show data from arduino to label

MIT App Inventor Help
1

i want to change max and min angle of servo, the + and - button it's all working to decrease or increase the variable, the problem is when i want to show current variable into label (for now its only increase and decrease minAngle value), its not showing anything just the default text

#include <Servo.h>

Servo myServo;

int minAngle = 30;
int maxAngle = 150;

const int joystickPin = A0;
const int servoPin = 9;

void setup(){
  Serial.begin(9600);
  myServo.attach(servoPin);
  myServo.write(map(analogRead(joystickPin), 0, 1023, minAngle, maxAngle));
}

void loop() {
  // Read joystick value
  int joystickValue = analogRead(joystickPin);
  int servoAngle = map(joystickValue, 0, 1023, minAngle, maxAngle);

  // Move servo to the mapped position
  myServo.write(servoAngle);
  delay(15);  // Allow servo to move

  // Check for Bluetooth commands
  if (Serial.available() > 0) {
    char command = Serial.read();

    // Update min angle if the command is 'm' (decrease) or 'M' (increase)
    if (command == 'm') {
      minAngle -= 1; // Decrease min angle
      if (minAngle < 0) minAngle = 0;  // Keep within bounds
      Serial.print("Min Angle: ");
      Serial.println(minAngle);  // Send updated min angle to the Android app
    } 
    else if (command == 'M') {
      minAngle += 1;  // Increase min angle
      if (minAngle > maxAngle) minAngle = maxAngle;  // Prevent min from exceeding max
      Serial.print("Min Angle: ");
      Serial.println(minAngle);
    }

    // Update max angle if the command is 'x' (decrease) or 'X' (increase)
    if (command == 'x') {
      maxAngle -= 1;  // Decrease max angle
      if (maxAngle < minAngle) maxAngle = minAngle;  // Prevent max from being less than min
      Serial.print("Max Angle: ");
      Serial.println(maxAngle);
    } 
    else if (command == 'X') {
      maxAngle += 1;  // Increase max angle
      if (maxAngle > 180) maxAngle = 180;  // Keep within bounds
      Serial.print("Max Angle: ");
      Serial.println(maxAngle);
    }
  }
}

Capture1
Capture11247×512 52.7 KB

2

How much text arrives on each call to Serial1.ReadSerial?

Maybe you have to accumulate all that text using a Text JOIN operation and only look after the last '\n' ?

3

im sorry how to know it, im still new in this app, i dont even know how to debug!

4
5

Dear @andruw_oei,
are you really using the serial line, with a cable between Arduino and Android device ? (not a Bluetooth ?).
Please be aware that the serial line is typically used by the Arduino IDE to exchange data from/to the development PC (via USB). Therefore your Arduino code is expecting the characters from the PC keyboard, not from the app, in my understanding.
Normally you want to communicate toward Arduino by using a BT, to allow the Arduino system, in your case the servo, to be free from wires.
More: your Arduino code, until it doesn't receive any character, it won't send anything. All the stuff of loop() is executen only if one character has been received.
Lastly (for now :smirk:) please be aware that the delay() function in some Arduino boards implementation of the compiler, it completely stops the CPU, therefore blocking any other activity (the serial line comm's, as well).
Best wishes.

Edit:
If you dig the forum you'll find tons of examples, mainly in @ChrisWard's and @Juan_Antonio's web sites

6

First, to debug your application, remove the condition that checks if the received text contains a given word. Just directly display the received text in a label without the condition.