Hello,

I am planing to do an IoT project for home automation and i need some help to design a smart switch circuit to control the home appliances with out changing the existing infrastructure. Below is the block diagram of a sample switch which can be controlled using a GPIO pin and need some capabilities to measure the current. Also the circuits needs some isolation for the AC main .



The basic requirement is to control the AC load using both the existing AC switch and the Digital circuit block "X" with some option to measure the current used. Please provide your suggestion on how to start with the same.

Regards,
Deepu

 

If the "AC switch" is closed, at least some of the current will flow through the "AC switch", so it will be impossible to measure current at point "X". If you want to measure current you need to install some sort of sensor (e.g, current transformer) on wire P (or N).

As drawn, if the "AC switch" is on, there's no way to turn the load of with the "X" device. Similarly, if the "X" device has closed the contacts, it's impossible to turn the load off with "AC switch". Is that what you want?

 

you may find this podcast interesting: http://www.theamphour.com/295-an-interview-with-omer-kilic/

 

If the "AC switch" is closed, at least some of the current will flow through the "AC switch", so it will be impossible to measure current at point "X". If you want to measure current you need to install some sort of sensor (e.g, current transformer) on wire P (or N).

As drawn, if the "AC switch" is on, there's no way to turn the load of with the "X" device. Similarly, if the "X" device has closed the contacts, it's impossible to turn the load off with "AC switch". Is that what you want?

Thanks for you suggestions. I understand the risk of switching of the device if any one of the switch is closed. But do u have some circuit option which u can suggest for this purpose ?

 

Thanks for you suggestions. I understand the risk of switching of the device if any one of the switch is closed. But do u have some circuit option which u can suggest for this purpose ?

Three way switch and single pole double throw relay