What other options do I have?
1) use external chips;
Like this? https://www.sparkfun.com/products/10136
This is the one I have http://www.ebay.co.uk/itm/251095501994and these on the way http://www.ebay.co.uk/itm/270758491217http://www.ebay.co.uk/itm/320736975011
Don't put capacitors on the pins, you'll overload the Arduino if you do.If the lamps work OK using hardware PWM (and you may not know whether they do without running them for a long time - as HazardsMind says, the controllers built-in to the lamps may not take kindly to PWM), but you can see strobing using the softPWM library, then you need to increase the PWM frequency when using SoftPWM. This is 490Hz by default for hardware PWM, but only 60Hz for the softPWM library.To increase the PWM frequency for the softPWM library:1. Simplify the timer ISR (the function "SoftPWM_Timer_Interrupt(void)" in SoftPWM.cpp). Get rid of the fade up/fade down code (you can do fading outside the ISR) and the normal/reverse PWM code. Move the declarations of local variables from the start of the function to where they are actually used. What you are looking to do is speed up the ISR substantially.2. Change the definition of SOFTPWM_FREQ in SoftPWM.cpp from 60UL to something higher. How high you can go depends on how much you have simplified the timer ISR.
Quote from: dtokez on Dec 25, 2012, 06:05 pmThis is the one I have http://www.ebay.co.uk/itm/251095501994and these on the way http://www.ebay.co.uk/itm/270758491217http://www.ebay.co.uk/itm/320736975011Bulb #2 will take PWM fine because it's obviously using resistors for current control (low power LEDs; power input 5W but light output 2.5W). Bulb #1 and #3 are using high power LEDs and will have driver chips.It shouldn't be possible to see flickering above 100Hz and at 60Hz any flickering should be barely noticeable (do you see flickering in a 20ma/5mm LED?). I still think your problem is just that you're making the driver angry.
Could I not just use a big resistor to current limit too the 3 x 1w LEDs, and chuck out the driver circuit?