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The initial bright pulse is possibly due to a large capacitance charging. You could try connecting a ~2k2 resistor from the + side of the LED to ground to allow the cap to charge with a trickle current before theLED is switched on.
I don't see any way can you apply PWM control to the 230V power input to get dimming.
From + side of the LED to the ground of the driver? did that, but resulted in smoke of the resistor overheating. maybe me having a wrong resistor, but the package says 2.2K Ohm 1/4W 5%. Shuld it be a 6 W resistor?
Hmm, the driver must be putting out more volts than the calculated value. The calculated 18V would have caused the resistor to dissipate ~ 150 mW (i.e. less than 1/4W). A 6W resistor would certainly be unnecessary. You mention 'package' so presumably you have some spare 2.2k 's? If so, try connecting four of them in series (i.e. daisy-chaining them) and connect the series string from the + side of the LED to the ground of the driver. Check they don't get hot when you switch on the driver. If they do, switch off immediately and you will know this resistor experiment won't work.
Got my new downlights. 4W. Tryed the same setup, with the one resistor that dident work (Got overheated) but this time it worked, supect i did something wrong in the old setup. Anyways, it fixed the light problem i had. But i have gotten a new problem.
I have added something to the design (see the attaced picture). A PWM controll board, to get more controll of the PWM output. But when i conect this to the setup the driver of the LED starts to make a worring buzzing sound. If i set the PWM frequency down to 50hz it dosent make any noice (but the light flickers). but if i turn it up to 500hz that are more normal it makes this sound. I suspect i have made something wrong with the grounding, maybe you can see the problem.
FYI: the PCA9685 is a readymade board, so the ground of the board is likely directly conected to ground both ways (to the audrino board and to the drivers ground)
Not clear why you would need that. The Arduino should be programmable to give all the control you want.
I have no knowledge of the PCA9685 so can't say why it would introduce your new problem. Maybe residual ripple on the driver is interacting with the PWM signal to give an audible beat frequency. Other forum members may have a better informed reason.
the arduino PWM output is limited to one frequency and have only 256 levels. But the PWM controll board have more controll of the PWM outputs with over 4000 levels and can select from a lot of varius frequencyes. And i need 60 PWM outputs to 60 downlights. The Audrino has very few. 5-12 depending on the board. But with the PWM controll board i can link many to one audrino. so i can controll all of the lights from one audrino board vs 6 audrino board.
is there any way to fix residual ripple if that is the case?
It's all guesswork if we don't have details of the innards of the driver, but you could try connecting a 50V (at least) rated capacitor of 100μF or so directly across the driver output. No guarantee it will work, though.
Here is the breakout board site and they have made room for a capacitor to solder on, but its between shared power and ground.
that is a another question. doses it matter that all of the grounds of 12 led lights are connected toghether? as they are here on this board. they have all one driver each.
It's all guesswork if we don't have details of the innards of the driver, but you could try connecting a 50V (at least) rated capacitor of 100μF or so directly across the driver output. No guarantee it will work, though.
What do you want to know about the driver? I can ask the supplyer any question about it. And will maybe a picture of the inside of the driver help?
Will try the
I culd not get a schematic from the producer, so we just have to try and fail. Have ordered the capasitators and gonna try that, and hopefully it will work. But they are gonna be connected across ground and positive by the output if the driver? close to the resistor we put in?
Tryed the capasitator, and it dident remove the sound, it might made it lower.
But talked with the support of the PWM board, and they said this after looking at the setup: "Some vibration in a PWM driver is expected. I suspect that the PWM switching frequency or one of its harmonics is exciting some resonance on the board. Often these resonances can be controlled by mounting the board to something solid and/or damping the enclosure with foam tape or other lossy material."
So i guess its okey then =) annoying sound, but i can allways soften the noice. But i fear when im going to have 65 of those drivers its gonna make some sound =P
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