Serial Read/Input Individual Characters

Other Hardware Motors, Mechanics, Power and CNC
4

My Arduino Software Solutions provide numerous ways to read text from Serial with their pros and cons
The non-blocking readLine sketch could be used

String input;
// Motor A

int enA = 9;
int in1 = 8;
int in2 = 7;


// Motor B

int enB = 3;
int in3 = 5;
int in4 = 4;

void setup() {
  Serial.begin(9600);
  for (int i = 10; i > 0; i--) {
    Serial.print(' '); Serial.print(i);
    delay(500);
  }
  Serial.println();

  Serial.println("Type A or B followed by time in sec, e.g. A55 or A 55");

  input.reserve(10); // pre-allocate some space

  pinMode(enA, OUTPUT);
  pinMode(in1, OUTPUT);
  pinMode(in2, OUTPUT);
  pinMode(enB, OUTPUT);
  pinMode(in3, OUTPUT);
  pinMode(in4, OUTPUT);

}

// read Serial until until_c char found, returns true when found else false
// non-blocking, until_c is returned as last char in String, updates input String with chars read
bool readStringUntil(String& input, char until_c) {
  while (Serial.available()) {
    char c = Serial.read();
    input += c;
    if (c == until_c) {
      return true;
    }
  }
  return false;
}

void loop() {
  if (readStringUntil(input, '\n')) {
    // go a line of input
    input.trim(); // remove any \r and leading/trailing space
    input.toUpperCase(); // a -> A etc
    char AB_type = input[0];
    input.remove(0, 1); // remove the char
    input.trim();
    long time = input.toInt(); // to int actually returns a long
    if (input != String(time)) {
      // invalid time
      Serial.print(input); Serial.println(F(" not a valid time"));
    } else {
      if (AB_type == 'A') {
        Serial.print(F("Picked A")); Serial.print(F(" with time:")); Serial.println(time);
        digitalWrite(in1, HIGH);
        digitalWrite(in2, LOW);
        analogWrite(enA, 200);
        delay (time * 1000);
        digitalWrite(in1, LOW);
        digitalWrite(in2, LOW);

      } else if (AB_type == 'B') {
        Serial.print(F("Picked B")); Serial.print(F(" with time:")); Serial.println(time);
        digitalWrite(in3, HIGH);
        digitalWrite(in4, LOW);
        analogWrite(enB, 200);
        delay (3000);
        delay(time * 1000);
        digitalWrite(in3, LOW);
        digitalWrite(in4, LOW);
      } else {
        Serial.print(AB_type); Serial.println(F(" invalid type, must be A or B followed by time in sec"));
      }
    }
    input = ""; // ALWAYS clear for next read
  }

  // other loop stuff here
}