I'm trying to make a little scene with a light turning off and on randomly, I tried adding a keyframe to the light power and applying a noise modifier. However the result is too "soft", I mean the light just get a little dimmer or brighter. I'd like to know if there was a way to make the light just turning off and on randomly without having to manually add keyframe through the whole timeline.
You need to have the noise modifier set up, as you already do. now add a limits modifiers. there are four checkboxes. Check Maximum Y, and Minimum Y, and set the maximum value to the maximum strength you want for your light, and set the minimum value to the minimum strength you want for you light. The animation will still look to smooth, so crank the strength value of your noise modifier until you get a curve that looks more binary.
I hope this helps :)
You can use the Noise Modifier: just increase a lot the strenght of the noise and the add a Limits Modifier, to clip the values between 0 and your maximum desired value
This is the quick and easy way. If you want more control you could use nodes (I am thinking of a noise modifier applied to the value of the strenght of the an Emission shader, using Greater Than and Less Than nodes), but you would need to use a mesh instead of a light object