I expect something like this can be easily and quite cheaply self build, like @Johanf pointed out already in another thread:
But instead make use of this dimmer board here (or two of them to get 8 channels):

I expect something like this can be easily and quite cheaply self build, like @Johanf pointed out already in another thread:
But instead make use of this dimmer board here (or two of them to get 8 channels):
