Change State

Projects Programming
1

Hi Guys,

Could someone help me please with the following code, the code is supposed to move a motor forward then backward after it detects the change state of a microswitch, it does this as expected but it keeps on repeating while the switch is closed, I only want it to cycle once after the change state and then wait for it to go from low to high again before another cycle?

#include <AFMotor.h>

const int stopLightPin = 2; // input from "STOP LIGHT" output
const int startPin = 9; // output via relay to start cycle
const int homePin = 11; // microswitch for home position
int buttonPushCounter = 0; // counter for the number of button presses
int buttonState = 0; // current state of the button
int lastButtonState = 0; // previous state of the button
int markState = 0; // variable for reading the pushbutton status

AF_Stepper motor(200, 2);

void setup() {
// initialize the LED pin as an output:
pinMode(startPin, OUTPUT);
pinMode(stopLightPin, INPUT); //Maybe change this to pulldown if erratic
pinMode(homePin, INPUT_PULLUP);

}

void loop() {
// read the state of the pushbutton value
buttonState = digitalRead(stopLightPin);
// check if the pushbutton is pressed. If it is, the buttonState is HIGH:
if (buttonState != lastButtonState) {
if (buttonState == HIGH) {
buttonPushCounter++;
motor.setSpeed(100);
motor.step(2450, BACKWARD, DOUBLE); // DOUBLE or INTERLEAVE or MICROSTEP!
delay(100);
motor.setSpeed(100);
motor.step(2450, FORWARD, DOUBLE);

} else {
// in other words do nothing
//digitalWrite(startPin, LOW);
}
delay(100);

}
}

regards

Andrew

2

You aren't setting lastButtonState after you read the new value.

3

I find it more sensible to save the previous button state just before reading it again.

void loop()
{
  lastButtonState = buttonState;
  // read the state of the pushbutton value
  buttonState = digitalRead(stopLightPin);

That way the two actions are close together in the code and make more sense to me when I read the code again.

4

I usually put that first thing after "if (buttonState != lastButtonState) {" because at that point you no longer need the old value and if the comparison is false (they are equal) there is no need to change lastButtonState.

5

Thanks guys, all working now thanks to you.

Andrew