Like I mentioned before, I have a few ultrasonic humidifiers; however, I'm not prone to disassembling them to see how they work. In fact, I know I don't have a variable speed fan, I just have a variable opening to meter the amount of humidity that comes out. So I can only guess that the pot you have may be a wire wound type of pot. Capable of handling more current than the regular sort of carbon based pots which are very common. Unless they're using the pot to already control some sort of power supply to the fan, which is also entirely possible.

Can you take pictures of the guts? Since you're wanting to replace the mechanical dial with something controlled solely via electronic means, you should be able to open it and take a few pictures. If you can get some numbers off the actual pot - - - .

I'm thinking if it's electronically controlled then you might be able to replace the pot with a variable resistance IC, one designed for such work. However, I know they don't handle much current, so exactly how we proceed we need to know what we're working with first.

Thanks Tonyr,
I traveled to our capital city and I'll be back home tomorrow. I'll dismantled the atomizer and give you the fine details. I'll also try to connect it's fan to PWM circuits and see whether it can work....
I'll also send some pictures as suggested....

All in all, I'm very much grateful for your responses and I'll make it a success...

 

One complaint I have about my humidifiers is that they tend to soak the floor around them. The reason why that happens is because it literally puts tiny tiny drops of water into the air. Many of those drops make their way to the floor before they can evaporate. I think if I could eject them into the air with greater force they might have a better chance of evaporating before they fall to the floor. I'd imagine that if you set your fan to a very low speed what you'll end up with is just a very slow pump to pump the water out of the humidifier. I'm getting the impression you probably won't like the results. At least with being able to vary the amount of air coming out of my humidifiers is that it still comes out with pretty close to the same velocity. Slowing the air stream down makes me think more of how lava comes out of a volcano, just barely over the peak of the cone only to flow down the slopes. Of course, the volcano I'm imagining isn't erupting violently, more like what is happening in Hawaii.

 

Hello members
I managed to dismantle the atomizer so that I could do a thorough inspection on it.
And now av landed on two methods that I can effectively be use in implementing my planned electronic control of the rate of humidification. But I still need some help.

One way involves linking the fan to pwm control circuit (as suggested by one member) but I'm avoiding this because it can hardly gives a linear control ; and also because the inbuilt fan is tiny and will not be powerful enough to blow out the mist, at low duty cycles.

The other way is, which I prefer using,through it's low water level sensor protection circuit. From my inspection the sensor is a resistive two terminal element with infinite resistance at low water level; and very low resistance when the vibrator is fully covered with water. Now, I plan putting in another resistive element (like an optocoupler )in series with this resistive sensor. And the said optocoupler be linked to pwm control circuit. Now, this is my first question ;
I've learnt that the sensor is stopping the primary oscillator. Do you think that by rapidly stopping and starting the oscillator with high frequency pwm circuit can affect the oscillator from producing mist in pulses?

 

this is the atomizer 's circuitry

Hello members
I managed to dismantle the atomizer so that I could do a thorough inspection on it.
And now av landed on two methods that I can effectively be use in implementing my planned electronic control of the rate of humidification. But I still need some help.

One way involves linking the fan to pwm control circuit (as suggested by one member) but I'm avoiding this because it can hardly gives a linear control ; and also because the inbuilt fan is tiny and will not be powerful enough to blow out the mist, at low duty cycles.

The other way is, which I prefer using,through it's low water level sensor protection circuit. From my inspection the sensor is a resistive two terminal element with infinite resistance at low water level; and very low resistance when the vibrator is fully covered with water. Now, I plan putting in another resistive element (like an optocoupler )in series with this resistive sensor. And the said optocoupler be linked to pwm control circuit. Now, this is my first question ;
I've learnt that the sensor is stopping the primary oscillator. Do you think that by rapidly stopping and starting the oscillator with high frequency pwm circuit can affect the oscillator from producing mist in pulses?