is it possible to do something like in C language "scanf" in arduino language? I need to ask to the user to insert some numbers through the Serial Monitor... i know that there is Serial.read() but i only get -1 and 0
here's an example of what i need:
Insert the actual time: _
it wait for the value and in the code i have -> variable = Serial.read();
SOLUTION by "waterlubber "
Serial.print("Enter the text for the user");
while(!Serial.available()){
//Do Nothing unless there is a reply!
}
variable=Serial.parseInt();
Serial.read() returns -1 if there is nothing available to read, so if you get this it suggests that you aren't using Serial.available() correctly.
If you want to receive a decimal number and know that it's available (for example because Serial.available() shows that there are bytes available to read, and you expect the client to have sent a decimal number) then you can use Serial.parseInt() to read it and return it as a number (rather than a sequence of ascii characters).
Serial.println("Insert the actual time (H): ");
hour=Serial.parseInt();
Serial.println("Insert the actual time (M):");
minutes=Serial.parseInt()
Serial.println("Insert the actual time (S): ");
seconds=Serial.parseInt()
the user can set the time that he want and the variables contain the decimal number that the uset set?
Conceptually yes, but after sending the message prompting the user to enter a number, you need to wait until they have actually done that before you try to read it. Otherwise the Arduino will time out after a second, return nothing and carry on to send the second prompt and so on, and go through that whole sequence before the user has actually got around to responding to any of the prompts.
If you don't need your sketch to do anything else while it is waiting, and if you're happy for the sketch to wait as long as necessary for the user to enter something, you could just insert a loop that calls Serial.available() repeatedly until it returns a positive result after each prompt.
Very simple servo test code where a servo control value is sent from the serial monitor to the arduino, the character string value is captured into a readString String, then the captured characters in the readString String are converted into an integer using the readString.toInt() function.
// zoomkat 10-14-11 serial servo test
// use a microseconds value like 1500 in serial monitor
// for IDE 0022 and later
// Powering a servo from the arduino usually DOES NOT WORK.
String readString;
#include <Servo.h>
Servo myservo; // create servo object to control a servo
void setup() {
Serial.begin(9600);
myservo.writeMicroseconds(1500); //set initial servo position if desired
myservo.attach(7); //the pin for the servo control
Serial.println("servo-test-22"); // so I can keep track of what is loaded
}
void loop() {
while (Serial.available()) {
char c = Serial.read(); //gets one byte from serial buffer
readString += c; //makes the string readString
delay(2); // allow buffer to fill with next character
}
if (readString.length() >0) {
Serial.println(readString); //so you can see the captured string
myservo.writeMicroseconds(readString.toInt()); //convert readString to number for servo
readString=""; //empty for next input
}
}
You should be aware that Zoomkat's code only works with the serial monitor, which sends all characters when you hit "send", and may not work at all with other line speeds.
It won't work with a proper terminal emulator, which sends each character as the key is pressed.
