I think this was caused by bounce in the switch contacts when releasing the switch.
I added a 10 msec delay as suggested by Banzi in "Getting Started with Arduino"
http://oreilly.com/catalog/9780596155513/
The delay eliminated the unwanted keypress messages.
- Code: Select all
/*
* Counting presses
*/
int switchPin = 2; // switch is connected to pin 2
int val; // variable for reading the pin status
int buttonState; // variable to hold the button state
int buttonPresses = 0; // how many times the button has been pressed
void setup() {
pinMode(switchPin, INPUT); // Set the switch pin as input
Serial.begin(9600); // Set up serial communication at 9600bps
buttonState = digitalRead(switchPin); // read the initial state
}
void loop(){
val = digitalRead(switchPin); // read input value and store it in val
if (val != buttonState) { // the button state has changed!
if (val == LOW) { // check if the button is pressed
buttonPresses++; // increment the buttonPresses variable
Serial.print("Button has been pressed ");
Serial.print(buttonPresses);
Serial.println(" times");
}
}
buttonState = val; // save the new state in our variable
delay(10); // de-bounce mechanical switch contacts
}