Help me

Hi Indukuri,

It's a very complicated topic. See this PDF document for some of the theory.

In summary one traditional solution is to use a triac. Motors are inductive and are a challenge to confirm your circuit is good without test tools, becuase you won't know the inductance (it's not specified on fans). It could destroy your circuit. Your circuit may also have a lot of noise when it switches, unless you have zero-crossing detection. Also, it's highly likely that you could damage your PC or yourself, if you've not worked with such a circuit before.

If you are curious to give it a go, be careful of circuits on the web, a lot of them are pretty ancient and don't have good practice.

I don't know if this is good practice, but a more modern approach could be to make use of solid state relays (internally they use dual SCRs). I have some personal circuits for control of heaters but I don't plan to share them because I would worry if they had a fault. To give you a hint, I used a SSR and an external zero crossing detection circuit despite them having it built-in. I wouldn't know if that would meet a motor need, my heater element had a lower inductance than a motor. Another point is that inductive loads usually don't use zero-crossing SSRs, so that would be 'for further study' and experimentation by you. You may wish to move this question in one of the forums for SSRs, I think there is one for Crydom. It's not an Arduino related issue. Also, you may wish to change the title - 'Help me' is as you know not appropriate, it doesn't explain what the post is about.

Shabaz

You are quite right in that its complicated.

Personally I would just go down to the local electrical store, and for a few dollars buy something that is approved and won't invalidate your insurance.

I never give advice on playing with Mains, because I can't check the work prior to it being connected, and I've seen some potentially deadly lash-ups.

The lighting fraternity used to use a 0-10v control system, and it may be possible to find some of these around.

They are generally used when DMX control isn't.

For ON/OFF control I highly recommend something that doesn't connect to a controller, and have used these previously.

http://www.shop.wattsclever.com/11-usa-socket

Some clever people have made a library to easily provide the sending end using a variety of devices so you have more than 3 devices available.

http://code.google.com/p/rc-switch/

mark

Shabaz

You are quite right in that its complicated.

Personally I would just go down to the local electrical store, and for a few dollars buy something that is approved and won't invalidate your insurance.

I never give advice on playing with Mains, because I can't check the work prior to it being connected, and I've seen some potentially deadly lash-ups.

The lighting fraternity used to use a 0-10v control system, and it may be possible to find some of these around.

They are generally used when DMX control isn't.

For ON/OFF control I highly recommend something that doesn't connect to a controller, and have used these previously.

http://www.shop.wattsclever.com/11-usa-socket

Some clever people have made a library to easily provide the sending end using a variety of devices so you have more than 3 devices available.

http://code.google.com/p/rc-switch/

mark