I am almost finished my project which involves controlling the speed of two single phase 220vac fans 75W each. The speed control doesn't have to be very precise, just speeding up or down depending on some temperature readings when necessary.
I have used two bpa16 600w triacs for the job, with an interrupt for zero-cross detection and by "cutting away" part of the sine wave I can effectively control the speed.
The problem I am having is the buzzing noise which turns out to be louder than I had anticipated.
I have read about other projects for controlling a motor similar to this, but it doesn't seem very simple. The simplest solution I have found is using a multipoint tranformer and a bunch of relays, to achieve various fixed speeds. Any other solution seems electronically complex.
I've seen this universal controller, which also seems simple, and might suit my needs.
Does anybody know of an already built shield for arduino to achieve this? Or something that might do the trick? And cheap?
Thank you very much.