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Topic: Fade LED in & out without interruptions ? (Read 765 times) previous topic - next topic


Thanks guys.  Here is my code.
I have put the fading led as the continually running code with checking for the temp as a sort of subroutine.  It should now continually fade the led in and out while periodically checking for the temperature. Did I get this right?

// LM35 Temperature Sensor and LCD 

#include <LCD4Bit.h>                                                                   // use of LCD4Bit library
                                                                             //create object to control an LCD.  
                                                                       //number of lines in display=2
LCD4Bit lcd = LCD4Bit(2);                                                       // create object to control an LCD # of lines in display=2

int inPin = 5;                                  // select the input pin for analog temp value
int inVal;                                     // integer value for input read from sensor
int i;
int samples[8];                                    // variables to make a better precision
long interval=4000;
long previousMillis =0;

void setup() {
 pinMode(13, OUTPUT);                                                              // set LED pin
 digitalWrite(13, HIGH);                                                       // light the  LED
 Serial.begin(9600);                             // set up Serial library at 9600 bps
 lcd.init();                                                                   // initialize LCD
 lcd.printIn("Welcome to my" );
 lcd.cursorTo(2, 0);                                                              // move cursor to line 2 position 0
 lcd.printIn("secret lab");

void loop()
 for(value = 0 ; value <= 255; value+=5) // fade in (from min to max)
   analogWrite(13, value);           // sets the value (range from 0 to 255)
                                     // waits for 30 milli seconds to see the dimming effect
 for(value = 255; value >=0; value-=5)   // fade out (from max to min)
   analogWrite(13, value);

     void TempTake()
      if (millis() - previousMillis > interval) {
                               previousMillis = millis();
           for(i = 0;i<=7;i++){                      // gets avg of 8 samples of temperature
            samples= ( 5.0 * analogRead(inPin) * 100.0) / 1024.0;
            inVal = inVal + samples;
             inVal = inVal/8.0;                  
             char buf[12];                                                             // "-2147483648\0" set buffer for itoa
             lcd.printIn(itoa(((inVal * 9)/ 5 + 32), buf, 10));        
             lcd.printIn(" Fahrenheit");
             lcd.cursorTo(2, 0);                                  // move cursor to line 2 position 0
             lcd.printIn(itoa((inVal), buf, 10));            // convert to string
            lcd.printIn(" Celsius");                                    lcd.leftScroll(20, 30);      // scroll dis 20 chars to left, delaying 30ms each
            inVal = 0;                                                 


Did I get this right

Sorry no.
You are fading in and out very quickly and then taking the temperature. It's not being done at the same time.

You need to write it so that loop() finishes very quickly and just calls the temperature reading, display and fade each time round.
Then in these routines you need to implement the a state machine for each process.
The state machine in the fade routine should check the timer and if 30mS has elapsed do an analogue write with the new value and set the time for the next update to the current time plus 30mS. If the timer has not elapsed then just exit the routine.

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