Reading part of an tx input and making it a value

Projects Programming
1

I'm trying to use my phone (iOS) to control a servo but the input is coming in as J0: ___, ___. How would I be able to take the first value as it ranges from 0-360 and make move the servo. I'm still very new to coding.

2

Good question. What is the rest of the story?

3

Welcome to the forum

Have you got control over exactly what the 'phone sends ?

If not, then, yes, you could parse out the numeric value near the start of the message for use in the sketch by using Serial.parseInt(). I am confused by your mention of a value of 0-360 to control a servo. Are you expecting the servo to move between 0 and 360 degrees ?

4

I'm trying to code a Boe-bot to make it move through my phone using a joystick. I'm also using an Hc-05 module if that helps. I can do the code I just don't know how to separate the value from the statement my phone sends.

5

Will the value always be in the same position ?

A small sketch for you to experiment with by inputting data into the Serial monitor


void setup()
{
    Serial.begin(115200);
}

void loop()
{
    if (Serial.available())
    {
        int x = Serial.parseInt();
        Serial.println(x);
    }
}
6

So you get text over the Serial line that looks like J0: XXX, YYY and you want to extract XXX and YYY ?

I would suggest to study Serial Input Basics to handle receiving the text into a buffer

and once it's in the buffer, you could do

int x, y;
char buffer[50]; // where the command gets into
...
// read the command
...
// parse the command
if (sscanf(buffer, "J0: %d, %d", &x, &y) == 2) { // could we extract 2 values with that format?
  // Yes —  here x and y are initialized with the 2 values 
  ...
} else {
  // No — buffer was not containing something matching the format `J0: XXX, YYY`
  ...
}
7

thanks so much I figured it out now.

8

I am glad you have got it working. What approach did you take ?

9

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