Adding a PIR to an existing Lighting Circuit

[Ydraiggoch]

I'm looking to add a PIR to an existing Hallway Lighting Circuit. Although, I will be rewiring the lighting circuit (upgrading the cables) so have an opportunity to change things slightly.

The current circuit is a 3-way switching set up in quite a long hallway. My Wife would like to keep the switches as they are. But I would like to add a PIR that fits in the ceiling (2 actually, but lets assume one just now) to stop the kids leaving lights on.

My thinking is, that the PIR would either need to be a 2-way switch, or an intermediate in order for all the switches (PIR and Hard switch) to work together.

So my question is, can you buy such a thing? (Can't find one that jumps out on Google)

or,

How else could I make this work. One idea would be to buy a std PIR and use an 'Octo relay' wired as a make shift Intermediate switch. But would rather not have an energised relay tucked away in the loft.

Any thoughts are appreciated!

 

[ban-all-sheds]

I don't think you've thought this through. If you have a PIR, what do you expect the other switches to do?

Imagine you had the current switches, and one of them was always operated by some invisible paranormal being who turned the lights on whenever someone entered the hallway, and then turned them off after a period of inactivity. Why would you need the other ones any more? When would you use them, and to do what?

Also what do you mean by "rewiring the lighting circuit (upgrading the cables)" - what's wrong with the existing cables? Why do they need "upgrading"?

 

[bernardgreen]

You are moving in the hall with the light switched ON. Because you are moving the PIR is active,......

Now you turn the light OFF at a switch ( PIR still active ) and leave the hall.

Lights are OFF and the PIR is timing out.

PIR goes inactive, the switch ( relay ) it is controlling changes state........Light comes back ON

When the next person walks into the hall ( light is ON ) the PIR goes active and the light goes OFF

 

[Ydraiggoch]

Wow......this has turned into some thread! But before I go into that, let me try answering some of the questions you guys put to me.

Had I thought it through? Yes to a degree. But I see I have missed a fundamental point that would defeat the whole purpose of what I am trying to achieve - No harm in that.

What would the other switches do? Well, assuming the circuit worked as I had intended, the switches would obviously turn the lights ON & OFF. Why? Why not? The PIR would have a photocell so that it will only activate in the evening. However, have you ever been in a situation where you are doing something in natural daylight, but you just need that little extra light? That would be one reason. Oh, and the Mrs wants to keep them, shes scared of Automation, and I'm scared of her

What do I mean by rewiring the lighting circuit? I mean taking out the old wiring and replacing it with new. Why? Because I am currently renovating the whole house and as I move along am rewiring it as I go. I estimate that the current wiring is 30 years old. So in my opinion, well worth doing.

Should I train the children? Firstly, they are not Dogs that are there to be trained. But I would bet that 90% of households have the same scenario whereby the children or certain members of the household have a tendency to leave lights on , doors open etc. And despite our best efforts of telling them, warning them & punishing them, it still continues. So, why not relieve the stress of it all and like any good Engineer, find an alternate solution?

So, I think that answers all the questions. And thank you for your solution. It was bernardgreen that made me realise my error. And as I did, I smiled at the simplicity of the error. But we live and we learn.

Now, if only the thread could accept the concept of the problem and work with the limitations given, it may have been an interesting to read peoples suggested solutions. Instead, it seems to have turned into a c*ck fight between regular posters.

You can't teach a man to fish if you're too busy arguing about how it should be done.