View Full Version : Ceiling Fan speed control circuit

11-22-2008, 10:04 PM
I want to automate some of my appliances and fixtures in my house and control them by a remote. I know the principle used for remote controlling of these(using relays etc). But how can i control speed of the ceiling fan using remote(like pressing one button to increase the speed or another to decrease the speed). I may even use a PIC microcontroller.

There are two ways i thought:

1. Using 5 relays in place of the 5-point rotary regulator switch. Like removing just the rotary switch and wiring the relays while keeping the resistor(coil) part as it is.

2. Using the small electronic regulators available and rotating them with small motors which are controlled by two switches or micrcontoller. But this method introduces humming.

So i want to control the speed of the fan using two push buttons. Can someone help me with a circuit. :idea:

11-23-2008, 12:06 PM
Google "Speed control AC motor Triac".

11-23-2008, 12:13 PM
I just remembered that the electronic dimmers available in the market are Triac based - BT139 seems to be the flavour.

Take a dimmer apart, use an optocoupler (like MOC3020) between its Triac and the uC and you are ready to rock.

11-23-2008, 04:27 PM
Thanks for the reply.

I will try the method soon. But the Triac/Scr used dimmers always produce hum in motors. They also cause RF fields which are detected in nearby Radios etc and eventually damage the fan motor except those which are tightly wound ones. Ideally the dimmers are made for incandescent light bulbs.

So I am thinking of using another idea of inserting capacitors(through relays) with different values in series with the Fan and its swithc.