Hello guys,
I know this post is a little old.....but I'm trying to build this circuit following the tutorial provided by Instructables:
I modified it for 120V 60Hz. It seems that the zero-crossing is actually working, but the LED doesn't turn on, not even blink 
The circuit is not complete, as I am missing the triac....but I wanted to test this part first. If the LED works, then the rest is pretty obvious.
Thanks in advance for your help.
Best,
JCS
Attached is the schematic on Proteus.
Here's the code.
/*
AC Voltage dimmer with Zero cross detection
Author: Charith Fernanado Adapted by DIY_bloke
License: Creative Commons Attribution Share-Alike 3.0 License.
Attach the Zero cross pin of the module to Arduino External Interrupt pin
Select the correct Interrupt # from the below table
(the Pin numbers are digital pins, NOT physical pins:
digital pin 2 [INT0]=physical pin 4 and digital pin 3 [INT1]= physical pin 5)
check: <a href="http://arduino.cc/en/Reference/attachInterrupt">interrupts</a>
Pin | Interrrupt # | Arduino Platform
---------------------------------------
2 | 0 | All -But it is INT1 on the Leonardo
3 | 1 | All -But it is INT0 on the Leonardo
18 | 5 | Arduino Mega Only
19 | 4 | Arduino Mega Only
20 | 3 | Arduino Mega Only
21 | 2 | Arduino Mega Only
0 | 0 | Leonardo
1 | 3 | Leonardo
7 | 4 | Leonardo
The Arduino Due has no standard interrupt pins as an iterrupt can be attached to almosty any pin.
In the program pin 2 is chosen
*/
int AC_LOAD = 3; // Output to Opto Triac pin
int dimming = 128; // Dimming level (0-128) 0 = ON, 128 = OFF
void setup()
{
pinMode(AC_LOAD, OUTPUT);// Set AC Load pin as output
attachInterrupt(0, zero_crosss_int, RISING); // Choose the zero cross interrupt # from the table above
}
//the interrupt function must take no parameters and return nothing
void zero_crosss_int() //function to be fired at the zero crossing to dim the light
{
// Firing angle calculation : 1 full 50Hz wave =1/50=20ms
// Every zerocrossing thus: (50Hz)-> 10ms (1/2 Cycle)
// For 60Hz => 8.33ms (10.000/120)
// 10ms=10000us
// (10000us - 10us) / 128 = 75 (Approx) For 60Hz =>65
int dimtime = (65*dimming); // For 60Hz =>65
delayMicroseconds(dimtime); // Wait till firing the TRIAC
digitalWrite(AC_LOAD, HIGH); // Fire the TRIAC
delayMicroseconds(8.33); // triac On propogation delay
// (for 60Hz use 8.33) Some Triacs need a longer period
digitalWrite(AC_LOAD, LOW); // No longer trigger the TRIAC (the next zero crossing will swith it off) TRIAC
}
void loop() {
for (int i=5; i <= 128; i++){
dimming=i;
delay(8.33);
}
}
