Why do you think that it will give out alot of heat ?
why wouldnt you isolate the gate as well ? many application notes reccomend to isolate the gate many circuits available...
I went through some old parts i had and turned out that i do have a MOC3020 and a 4n25 optocouplers. The MOC3020 appears to be equivalent to MOC3021.
Finally i will proceed with the project and i am going to use optocouplers for both ZC detection and driving the triac.
I have some other questions concerning the same project. I would like to add a 7 seg. display but it seems that the uno only has PORTD available with 8 i/o pins connected to it. Also it looks like im going to need pin 2 or 3 for the ZC detection interrupt.
I think i should i create a new thread for this, yes ?
Hello everyone.
I would like to say that i have built a modified version of the circuit mentioned in post 4 and it works just fine. I used a diode bridge and the 4n25 to detect the zero crossing point and a MOC3060 to drive a BT136. I have noticed that the theoretical firing time is a quite a bit different than the actial zero crossing time but that is normal due to the transformer and the dioes.
THANK YOU ALL !
Does anyone know how could i possibly use some other pin for the zero crossing detection ? I mean that the attachInterrupt function only works on pin2 and 3 on the uno board. I happen to need theese pins (the whole PORTD) for the 7 segment display. Is it possible that i detect the pin state change on other pin such as pin 11 for example ?
I think no, there is no way that we can do that, because the interrupt circuitry is built into the microprocessor that is the heart of the microcontroller.
just a thought, at least how i should do it: take a normal dimming circuit with a potentiometer and replace the potentiometer with an LDR... With the arduino you can drive a led with PWM (analogwrite) which will illuminat the LDR.
I don't think it will be very lineair but it will work..
You can use "Pin Change Interrupt" instead of the "External Interrupt". That works on any pin.
That would work but sure not accurately.
That sounds nice. Could you suggest some code example ?
Except that i will have to manually keep track of the last pin state, is there other significant difference ?
As I read it, Pin Change does not mean that you can use any pin to cause an interrupt. It means that the interrupt will trigger on the change of state of the pin, that is rising or falling.
RTFM?
Datasheet if you prefer knowing what is going on, Arduino reference if you prefer details hidden:
which has link to
Well, look at that. The Arduino gets more and more interesting as time goes on!
Thank you all so much !
I have started the trial and error procedure. I will soon build the project on a board and let you know how it went 
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