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Topic: Digital 12 socket light dimmer. For christmas! (Read 3 times) previous topic - next topic


Dec 01, 2011, 05:04 am Last Edit: Dec 01, 2011, 05:10 am by GTech13 Reason: 1
Sorry I didn't get back to you.  I used it for Halloween and had it flicker for a "loose wire" simulator.  The digital control works well and I decided to forget the IR for now in place of bluetooth!  I made a socket inside for a RN-42 module I move around to whatever current project I'm working on and I send it commands from my phone with a program designed in AppInventor.  Also works well but I need some emergency help on the dimming.  I absolutely cannot get solid code to work well for dimming.  I have lots of snippets that sort of work under certain conditions (one light, one level, etc) but I'm incredibly frustrated and the Christmas tree is ready.

I really need to fix the phase thing and then dimming should be incredibly easy.  What I would like to know from the community is how a LED (ac optoisolator) will respond to being driven off the secondary of the transformer.  When resistor only driven will the response be in phase with primary mains voltage?  I think it would also be 90 out out of phase so then I can maybe see about RC driving the LED but my voltage may be too low (the capacitor would need to be pretty big).  What do you think?  Your quick responses will be greatly appreciated.


EDIT:  Basically I can only drive from mains with a RC combo (thus causing my problem) and may only be able to use a resistor from the secondary for the opposite reason. I think my secondary is only about 7vac thus needing only about 500 ohms of resistance/reactance.  (a 5uF cap + R100 then)


Update:  The forums seemed to be down earlier and I had some extra time so I connected to the secondary with a resistor only and voila! perfect zero crossing detector.  I'm sure if there was some sort of inductive or capacitive load on the secondary this would mess things up but it only runs the uC.  I'll try to post a video sometime.  I'm off to write the new code, hope it is as simple as I think it will be.


This is awesome, great work with AppInventor!   :D


hi dude  i am also doing the same sort of project
please send me the code of ur porject  thanku ;)

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