Raspberry PWM

[matys1701]

Hello, I am new to FPP and I want to connect SSR board directly on GPIO pins, but it can go only high or low. Is there any way to use software PWM? Or how can I controll SSR board with FPP without external hardware?

[AAH]

  Even if you work out the PWM ability you may have issues. Most SSR's have zero crossing for the turn off the the internal electronics. In order to get reliable dimming the circuitry should be detecting the incoming 50 or 60Hz mains frequency and should be dimming based on the zero crossings of the voltage. There's also a problem when dimming sine waves in that it's not a linear relationship between "on time" and output brightness. There's also a big difference between the brightness curves for LED and incandescent lights. Incand will heat up and emit light regardless of the voltage whereas LED doesn't emit light until you hit a voltage threshold which means that they are often dimmed only over a small portion of the mains waveform.
  It's complicated to try to get the correct results with mains voltage dimmers. That's 1 of the reasons I've never worried about building a mains voltage dimmer

[CaptainMurdoch]

FPP doesn't have any PWM channel output capabilities currently.  I have it on my (long) ToDo list to look at adding PWM capability to the GPIO Channel Output using SoftPWM in WiringPi, but haven't got around to it yet.  This would only work for DC SSR's I believe and is one reason I haven't looked into it so far.

[matys1701]

Thank you a lot. Now I know what I can/can not do