Go Down

Topic: Automation in existing home using Arduino (Read 4 times) previous topic - next topic


Thanks, your info seems to be helpful. Tried to do some google on optoisolators but couldn't figure out the exact purpose and how they could be used in the current situation I think the stuff is getting complex for me to handle. Will have to do some background study on the suggested options.

My first impression was that optoisolators act more like a fuse breaking the circuit on detecting additional voltages, but wasn't sure how it could be used in conjunction with by the arduino to track if the device is powered on. Any links for reference would be helpful. Correct me if I'm wrong.

Hope the optoisolator idea works for you. Keep me posted.


Regarding optoisolators, here's a recent thread on this very subject.  Notice how the idea evolves as you read down through the thread.  The poster is doing exactly what we discussed.


One thing I want to mention just to be sure you're aware.  The voltages you'll be working with can blow an arduino to pieces if you mess up.  It can also actually kill you.  Yes, I know you know this and will take care, but there may be some young person that reads this thread and gets the idea to just jump in there and start hooking things together.  This paragraph is mostly for them.  Don't do it if you don't know what the heck you're doing, or at least have your life insurance paid up to date.
Trying to keep my house under control http://www.desert-home.com/


Jan 09, 2013, 02:09 pm Last Edit: Jan 09, 2013, 02:11 pm by veseo Reason: 1

we used the following scheme to do that job. Basically the wall switch power a 220V coil of a relay, one contact goes to the Arduino to know the position of the wall switch, the other goes to the lamp via a relay that is on the Arduino it self.
The NC relays is keep open by the Arduino, so the wall switch will never act on the lamp while the Arduino is powered, than the Arduino can drive the lamp using the other relay.

So, the Arduino knows about the wall switch position and drive the lamp. If the Arduino is off or broken, the NC relay will control the lamp directly from the wall switch.

This scheme is used in a home along with the Souliss project, so the lamp is either controlled via Android or Modbus.

Please take care, because not always you can try the 220V twice :) and get help if your local law or your knowledge request it.

Note that the wiring of the GND pin is wrong, you need a pull-down to an input pin.

If you need more, just ask.

Souliss - Open-source Distributed Home Automation with Arduino and Android

Follow at @soulissteam




I am having two way switches in my room. I am a newbie planning to do some home automation using Arduino and got a few questions in this directions.

--> I am interested to keep the existing AC circuit intact. Would it be possible to add the arduino controlled output into the existing circuit making it a 3-way switch?

Please do let me know of any other alternative approaches if the proposed approach doesn't work.

The overall idea is to have my existing two way switches intact and add an additional switch thats controlled by Arduino enabling home automation.

Any help is appreciated. Thanks.

Hello npadma:

The same that you want I thought it some time ago, and as I did not find anything that it was able to solve my aims, I developed my own solution. I have developed a home automation system based at the Arduino platform and called functiodomo that it lets you to control any electric compontent at your home without modify your electrical instalation.

You can find more information about it here:

http://arduino.cc/forum/index.php/topic,116788.0.html (english arduino threat of the functiodomo system)
http://www.functiodomo.com/en/functiodomo_web/index.html (english version of www.functiodomo.com)
http://functionars.dyndns.org/functiodomo_wp/ (spanish blog with information and documentation about the system)

You can ask me anything that you want about it. I will try to answer you.
José Antonio Castillo Rodríguez
Responsable de diseño de producto
Functio & Ars S.L.



Thanks. The NC Relay looks as an interesting option, but still not sure if it could be applied to the 2-way or 3-way switch circuits for controlling and monitoring the status of the circuit.

I'm sorry, I couldn't exactly get the circuit diagram you explained. Would be great if you can help me with some visuals.

From what I understood: in addition to the traditional light-switch circuit, one terminal of the switch is connected to the arduino and the other is connected to the NC relay. Please do let me know if my understanding is correct, before I go further on this.

Go Up