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(a)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(a)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);
}
}