[sudo-discuss] multiple lamp dimming with a single arduino

[robb]

and there are 5 timers on the mega...
:/

On Wed, Aug 24, 2016 at 10:40 PM, robb <sf99er at gmail.com> wrote:

> weird i was just about to compose an email about one other possible
> solution:
> As long you create a new 'board' entry in the arduino boards.txt file
> showing the 20Mhz Fclock value the time based functions should work fine as
> they use the Fclock value defined in that board selection to setup the
> proper timing value for timer0. Same with the hardware serial baud rate
> calculations used in serial.begin function.
>
> On Wed, Aug 24, 2016 at 10:38 PM, Jake <jake at spaz.org> wrote:
>
>> robb,
>>
>> since we got the zero-crossing detection working, now it's a matter of
>> deciding how many lamps to control with a single arduino.  I believe this
>> instructable shows software that doesn't rely on the chip's timer being
>> tied to the triac control pins, meaning that it could be used to control 8
>> or more triacs with a single plain arduino.
>>
>> http://www.instructables.com/id/3-channel-Dimmerfader-for-Ar
>> duino-or-other-microco/?ALLSTEPS
>>
>> /*
>>  AC Light Control
>>  Ryan McLaughlin <ryanjmclaughlin at gmail.com>
>>  with slight modifications
>> */
>>
>> #include <TimerOne.h>           // http://www.arduino.cc/playgrou
>> nd/Code/Timer1
>> #define PINS 3
>> volatile int pinCount[PINS];    // make volatile to make available in
>> interrupt
>> volatile boolean zero_cross=0;  // Boolean to store a "switch" to tell us
>> if we have crossed zero
>> int AC_pins[] = {3,4,5};        // Stup the pin numbers
>> int AC_dim[PINS];               // Holds Dimming levels (0-128)  0 = on,
>> 128 = 0ff
>> int freqStep = 78;              // Set the delay for the frequency of
>> power (65 for 60Hz, 78 for 50Hz) per step (using 128 steps)
>>                                 // freqStep may need some adjustment
>> depending on your power the formula
>>                                 // you need to us is
>> (500000/AC_freq)/NumSteps = freqStep
>>
>> void setup() {
>>   for(int a=0; a < PINS; a++) { //set the pins to output
>>    pinMode(AC_pins[a],OUTPUT);
>>    pinCount[a] = 0;             // keeps track of the time in the cycle
>>    AC_dim[a] = 0;               // dimming level set to zero
>>   }
>>   attachInterrupt(0, zero_cross_detect, FALLING);  // Attach Interrupt to
>> Pin 2 (interrupt 0) for Zero Cross Detection
>>   Serial.begin(9600);
>>   Timer1.initialize(freqStep);                     // Initialize TimerOne
>> library for the freq we need
>>   Timer1.attachInterrupt(dim_check, freqStep);     // Use the TimerOne
>> Library to attach an interrupt
>>                                                    // to the function we
>> use to check to see if it is
>>                                                    // the right time to
>> fire the triac.  This function
>>                                                    // will now run every
>> freqStep in microseconds.
>> }
>>
>> void zero_cross_detect() {        // function to be fired at the zero
>> crossing
>>    zero_cross = 1;                // set flag to tell dimming function
>> zero cross has occured
>> }                                 // End zero_cross_detect
>>
>> void dim_check() {                   // Function will fire the triac at
>> the proper time
>>  if(zero_cross == 1) {               // First check to make sure the
>> zero-cross has happened else do nothing
>>    for(int a=0; a < PINS; a++) {
>>      if(pinCount[a] >= AC_dim[a]) {       // Check and see if i has
>> reached the dimming value we want
>>        digitalWrite(AC_pins[a], HIGH);    // Fire the Triac
>>        delayMicroseconds(5);              // Pause briefly to ensure the
>> triac turned on
>>        digitalWrite(AC_pins[a], LOW);     // Turn off the Triac gate
>> (Triac will turn off at the next zero cross)
>>        pinCount[a] = 0;                   // Reset the accumulator
>>        zero_cross = 0;                    // Reset the zero_cross so it
>> may be turned on again at the next zero_cross_detect
>>      } else {
>>        pinCount[a]++;                     // If the dimming value has not
>> been reached, incriment the counter
>>      }
>>    }
>>  }
>> }
>>
>>
>> void loop() {
>>   // This is simply making all outputs cycle through bright-dark, out of
>> time with each other.
>>  for(int i=0; i<127; i ++) {
>>    for(int a=0; a < PINS; a++) {
>>       int ii = i+42;               //this is the bit that puts the
>> blinking lights out of sync with one another
>>       if(ii > 127) ii -= 127;
>>       AC_dim[a] = ii;
>>     }
>>     delay(50);
>>   }
>> }
>>
>>
>
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