5 replies to this topic

[coder25]

I was wondering how something like this is done when all the electrical wiring is already completed.
I'm talking specifically about the switching on and off part. Can you do it without messing with the electrical wiring ?

[Volte]

You mean like making a light go off using a remote or something?
What controls your lights going on and off is just the light switch. It completes the circuit when you switch it on and opens the circuit when you switch it off. All you need is something that lets you open and close that circuit.

[coder25]

Yes, controlling it by an external device.
So this something that lets you open and close the circuit, wouldn't that device require to tamper with the wirings ? What if multiple lights have to be controlled ?
I'm not too sure how the system works and I'm having trouble picturing it as well.

[wim DC]

Well, there obviously is some wiring to do. But you don't have to break walls in search of the current wires. You just take off the current switch and replace it with a switch that you can control with the computer/other device. So for 1 light, after taking off the switch you got 2 wires which you attach to the new switch. And unless it's wireless you'll need some cable to connect that switch to your computer/other device.
Assuming it's an AC device, it doesn't even matter whether wire 1 is in slot A and wire 2 in B or vica versa.

Rewiring a switch isn't hard, and it isn't unsafe when you turn down the power in your house/room ;)

[John]

Rewiring is not necessary if you use power line communication. AC operates at 120V at 60Hz (in the US). If you broadcast your communication protocol at different frequency, it can travel through your existing wire without interfering with any devices. You would just need a way to encode/decode the protocol at each end. Once a particular receiver decodes a message, it can flip a relay cutting the source voltage off or letting it through, respectively, turning a light off or turning a light on.

[lor]

Reminds me of this:

Emergency Party Button