Communication between Arduino Nano 33 BLE and Due

Question

I have a project and this project depends entirely on the communication between Arduino Due and Nano 33 BLE.
I want to send data via UART from the sensor located in the Nano as float data, and I receive it in the form of a float as well.
But by using Serial.read(), the data will be send as int, and by using Parsefloat, the information is received incorrectly.
Is there a way to send sensor data from nano to Due without error? And in the right form?

Here is the Nano code:

float h = 22.5;
float x, y, z;
int i = 0;
unsigned long previousMillis = 0;

const long interval = 500;
void TimerOhne();
void Acceleration();
void setup()
{
    Serial.begin(9600);
    Serial1.begin(9600);
    if (!IMU.begin())
    {
        Serial.println("Failed to initialize IMU!");
        while (1)
            ;
    }
    Serial.println("Read the serial");
}

void loop()
{

    // TimerOhne();
    Acceleration();
}

void TimerOhne()
{
    unsigned long currentMillis = millis();

    if (currentMillis - previousMillis >= interval)
    {
        // save the last time you blinked the LED
        previousMillis = currentMillis;
        Serial1.write(h);
        Serial.println(h);
        Serial.println();
        Serial.print("i ist: ");
        Serial.print(i);
        Serial1.write(66);
        Serial1.write(i);
        Serial.println();
        i++;
    }
}

void Acceleration()
{
    if (IMU.accelerationAvailable())
    {
        IMU.readAcceleration(x, y, z);
    }
    unsigned long currentMillis = millis();

    if (currentMillis - previousMillis >= interval)
    {
        
        x = x * 100;
        y = y * 100;

        Serial1.write(4);
        Serial1.write(x);
        Serial1.write(6);
        Serial1.write(y);
        Serial1.write(8);
        Serial1.write(i);
        i++;
        Serial.print("X ist:  ");
        Serial.println(x);
        Serial.print("y ist:  ");
        Serial.println(y);
    }
}

Here is the Due code

float r;
unsigned long previousMillis = 0;
const long interval = 500;

void setup()
{
  // Begin the Serial at 9600 Baud
  Serial.begin(9600);
  Serial1.begin(9600);
}

void loop()
{
  unsigned long currentMillis = millis();

  if (currentMillis - previousMillis >= interval)
  {
    previousMillis = currentMillis;
   
    r = Serial1.read();
   
    Serial.println(r);
  }
}

Answer 1

To transport an float in binary you have to send the bytes of the float as a byte array.

Serial1.write((const uint8_t*) &x, sizeof(x));

you can receive them as

if (Serial1.available()) {
  Serial1.readBytes((uint8_t*) &x, sizeof(x));
  ...
}

Note: this assumes the float type is encoded the same way on both sides, which is true since both MCU are ARM architecture.

---

If you want to transport the number as text and parse it on the other Arduino, use Serial1.print(x) to send it and you can use the parseFloat() function.

if (Serial1.available()) {
  x = Serial1.parseFloat();
  ...
}