I'll do my best to explain my issue, here goes..
A simple closed switch on D2, sets D13 HIGH using the PULLUP method and fires a Solenoid. I NEED a delay of about 3000ms from the time the switch is closed before the Solenoid kicks on (I got that part working) My problem is safety, I need the Solenoid to shut off Immediately and as soon as the switch opens. It's not doing that now because of the built in delay. Is there a different way to Code this to make the Solenoid shut down as soon as the switch opens?
**(I simplified the code using the LED for testing purposes. I'm using a MOSFET on that pin before the Solenoid)
const int BUTTON_PIN = 2; // the number of the switch pin
const int SOL_PIN = 13; // the number of the Solenoid pin
int switchState = 0; // variable for reading the switch status
void setup() {
// initialize the Solenoid pin as an output:
pinMode(SOL_PIN, OUTPUT);
// initialize the JB4 pin as a pull-up input:
// the pull-up input pin will be HIGH when the switch is open and LOW when the switch is closed.
pinMode(BUTTON_PIN, INPUT_PULLUP);
}
void loop() {
// read the state of the switch value:
switchState = digitalRead(BUTTON_PIN);
// control the Solenoid according to the state of button
if(switchState == LOW) { // If switch is closed
delay (3000);
digitalWrite(SOL_PIN, HIGH); // turn on Solenoid
}
else { // otherwise, switch is not closed
digitalWrite(SOL_PIN, LOW); } // turn off Solenoid
}
What a phenomenal tutorial! I was able to wrap my head around the example for your specific task. I just have to brain storm and apply the millis() to what I need it to do.
The basic flow will be
if switch is closed and flag reset, record start time and energize solenoid, set flag
if switch is open, de-energize solenoid, reset flag
if flag is set then check current time - start time and if exceeded, energize solenoid and set flag
You want to click a button, wait 3 seconds then turn on something.
Then, when the button is released, turn it off. - Even if it hasn't yet been turned on.
If so.. Here's the silver bullet approach...
#include <mechButton.h>
#include <idlers.h>
#include <timeObj.h>
#define BUTTON_PIN 2 // Pin we'll hook the button to. The other side hooks to ground.
#define SOL_PIN 13 // Usual pin number for built in LED.
timeObj vTimer(3000,false); // Setup a 3 sec timer.
mechButton button(BUTTON_PIN); // Set button to pin 2.
// Your standard sketch setup()
void setup() {
Serial.begin(9600); // Fire up our serial monitor thing.
pinMode(SOL_PIN,OUTPUT); // Set up the LED pin for output.
button.setCallback(myCallback); // Set up our callback. (Also calls hookup() for idling.)
}
// This is the guy that's called when the button changes state.
void myCallback(void) {
Serial.print("Button just became ");
if (button.trueFalse()) {
Serial.println("true!");
digitalWrite(SOL_PIN, LOW);
} else {
Serial.println("false!");
vTimer.start();
}
}
// Your standard sketch loop()
void loop() {
idle(); // Let all the idlers have time to do their thing.
if (!button.trueFalse() && vTimer.ding()) { digitalWrite(SOL_PIN, HIGH); }
}
If you are interested in trying this, you will need to install LC_baseTools from the library manager.
@jimlee Yes, exactly! micro switch is pressed full throttle.. 3 sec delay then solenoid fires... If switch is opened, cut off solenoid immediately. I will try that code, thanks for your help!!
Using of delay() will block reading the button, resulting in missing some events => use millis() instead of delay, See how to use millis() instead of delay()
To detect the press event, detect the state change of instead of checking the state. => it will be simple if you use ezButton library. This library has isPressed() function and debouncing functionality
sir-william: @jimlee Yes, exactly! micro switch is pressed full throttle.. 3 sec delay then solenoid fires... If switch is opened, cut off solenoid immediately. I will try that code, thanks for your help!!
if closing the valve is essential I would think about circuitry that switches off the solenoid even in case of a failure of the microcontroller.
I mean something like how emergency-buttons are wired. Normally closed. Any opening at any place initiates emergency-cut-off. In your case this could be something like a watchdog-circuitry that must get an impulse every second or even more often to keep a relay-contact closed (normally opened). As soon as the pulses don't come anymore relay opens solenoid cutoff.
