Send data from button to serial. Question post.

Other Hardware LEDs and Multiplexing
1

Hello everyone.my name's chatchai.this's my first port and sorry for my english. I have problem with send data to serial. when i push button have a lot data to sent.this my code.

const int led = 13;
const int buttonP = 2;
int btnstate = 0;

void setup() {
// initialize the digital pin as an output.
Serial.begin(9600);
pinMode(led, OUTPUT);
pinMode(buttonP, INPUT);
}

// the loop routine runs over and over again forever:
void loop() {

btnstate = digitalRead(buttonP);
if (btnstate == HIGH)
{
digitalWrite(led, HIGH); // turn the LED on (HIGH is the voltage level)

Serial.print("13");

}
else
{
digitalWrite(led, LOW); // turn the LED off by making the voltage LOW

}

from above code.I need to sent value=13 to serial when i push button.but I got many 13.please see my picture.
Thank you.

arduino1.png
arduino1.png1920×1080 618 KB

2

That is because you get a 13 each time round the loop while the button is held down.
You just want one when it is first held down. Therefore you have to remember what the last state was and compare it to the current state.
See this:-

3

Thank you. I will applied with my code.