Java InputStream float value too big

Question

I am struggling how to read float value from inputStream. I tried before with BigDecimal, and it was not possible to get the correct number

Problem: im expecting V ~0.00 - 1.50, Later up to 55.00

While V = ~0.00, it prints 6.336931E-10, V = ~1.05 - 2.53483E-9

Java code:

DataInputStream inputStream = null;
                try {
                    inputStream = new DataInputStream(btSocket.getInputStream());
                   
                    float f = inputStream.readFloat();
                    System.out.println(f);


                } catch (IOException e) {
                    e.printStackTrace();
                }

To visualize sent values:

Answer 1

To read float values with DataInput, they need to be written in a compatible format, which is essentially a 32-bit IEEE 754 float.

Your Arduino code appears to be writing them as new-line separated decimal strings.

Those won't work together.

If you want to modify your Java to read text, something like this should work:

try (var is = btSocket.getInputStream();
     var r = new InputStreamReader(is, StandardCharsets.US_ASCII);
     var lines = new BufferedReader(r)) {
    while (true) {
        String line = lines.readLine();
        if (line == null) break;
        float f = Float.parseFloat(line);
        System.out.println(f);
    }
}