Two PIRs to one set of lights.

[1974stephen]

Out of interest how old are the PIR's and do you know how much was paid for them? Quality PIR's should be able to work in the manor described in the diagram above, afterall it's only like wiring in on override switch on the PIR which I have done sucesfully.

Getting in an electrician maybe a waste of time if he turns round and describes your PIR's as "a load of old crap" if he can't make them operate in the way you have tried either (as you appear to have it wired correctly).

Rather than messing with relays you may be better investing your money in a pair of quality PIR's, but before installing them wiring them up in a trial to check that it does work first, as if it doesn't you can re-package them and hopefully take them back to where you bought them from.

 

[cpocal]

Thank you all for your time on this.

I couldn't upload the diagram that would have showed it was wired correctly as Taylors diagram. Here is some additional information that might be of interest and some help.

The lights and Gate PIR were installed 3 years ago by an electrician who provided both PIRs, invoiced at £29.95 each, as I was going to have a similar set-up for back garden lights but was too expensive at the time. Both are the same as I wanted a small lens and set at a height of 4 feet so that an animal would not trip it but a child would. It worked so well that I wanted it to work from the house also. As you can see by the diagram the outside power is provided by a separate mini consumer unit (garage CU) and has a 6A lighting MCB and a 16A ring MCB controlled by an RCD. I wanted it this way so that a burglar could not short out the house RCD by tampering with the outside lights and the power to the outside sockets fails at 6 pm via a timer. Incidentally, all outside cabling is armoured and the earth is connected to an earthing rod. I haven’t included the earth in the diagram. It all works fine if I disconnect either the house PIR or the Gate PIR but not with both connected.

My nephew is an aircraft electrician and it was he that suggested I use relays.

In the meantime I will look at replacing both PIRs as you suggest Stephen.

Sincerest gratitude, Chris

 

[Space cat]

Spacecat, can I get a relay that will direct the power from whichever PIR is activated 1st

You can do this but it's complicated and will certainly require at least two multipole relays. Meanwhile, try this simple test on your PIRs.

Connect a single PIR to your lights and check that it works. Now add a simple light switch across the working PIR, ie from live to switched live. This simulates a second PIR. Switch on and off. Does the PIR do anything unexpected, like keeping the light on until it times out? Repeat this on the other one.

Here's one more idea. To get around the problems that might arise with a PIR driving only a relay coil you could put two of your lights directly onto the PIRS, one on each, with relay coils in parallel. The contacts then control the other lights. Each PIR will then activate it's own light plus the middle ones but not the one at the far end. That one will activate when someone comes within range of its own PIR

 

[bernardgreen]

It isn't clear how the power is feed to these lamps and PIRs

Is one PIR fed from the house and the other PIR from the

a separate mini consumer unit (garage CU)

.

If that is the case then connecting them in parallel is NOT an option as by doing so you have connected two seperately fused supplies to each other.

power to the outside sockets fails at 6 pm via a timer

I assume the power to the gate PIR is not switched by this timer. If it was paralleling the two supplies would effectively by pass the timer and feed the sockets with power via the cable between the PIRs.

 

[Space cat]

bernardgreen wrote:

If that is the case then connecting them in parallel is NOT an option as by doing so you have connected two seperately fused supplies to each other.

Good point. Cpocal, you need relays.

 

[cpocal]

Space Cat , yes it does react strangely if I attach an ordinary light switch and just flick the switch on and off again. It seems to restart the timer on the PIR and so if that is the case it would appear that one PIR being activated, i.e. the Gate PIR, turns on the lights and then when the 2nd PIR is activated, i.e. the house PIR by someone continuing into the house the PIRs must then restart the others timer until one of them breaks the chain although this period is variable and has no set pattern no matter what I do with the timers.

The idea you have is great except that I really need all 3 lights to activate as the house PIR is only activated when someone enters or leaves the front door, otherwise anyone at the front door would be in darkness until someone opened the door.


Bernard, Anything to do with the outside power be it sockets or lights and PIRs are connected ONLY via the mini consumer unit I described earlier and so are on the respective 6A or 16A circuit. The mini consumer unit is near the main consumer unit.

Reading on the internet I saw something called a diode that only allows current in one direction only now if it were possible to achieve that on the switch live at the PIRs then the power would only be able to travel from the activated PIR and not upset the non activated PIR. Is it possible to do this on a 240v circuit as what I was reading about concerns electronics? This is hard for me to make myself understood so I hope you'll bear with me while I too help to find a solution to this.

 

[cpocal]

Bernard, no the PIRs are not connected to the sockets timer as that switches the sockets OFF after dark also I need to be able to control the lights via the PIRs' individual timers. Ideally, the house activated PIR only needs about 20 seconds as sufficient time to light someone's exit from the property. Whereas, the Gate PIR maintains activation for 5 minutes to allow for doorstep transactions etc.

 

[Space cat]

Sorry to disappoint you but diodes won't help. A diode is an electronic device that allows current flow in one direction only. Unfortunately you are working with AC here so current is already flowing both ways through both pirs and all the lamps.

In theory you could use four diodes at each end to convert the AC from your PIRs to DC. These same diodes would also isolate each PIR from the other. The snag with diodes is that they are inclined to go bang every time a bulb fails. (Halogen filaments can draw huge current spikes in their final milliseconds.) You will be better off with relays. To get round possible loading problems you can always add extra lamps in parallel with the relay coils. Ordinary filament bulbs of modest power will do - and if you put them inside the house they will inform you every time a PIR is activated.

 

[cpocal]

Hi Space Cat, you haven't disappointed me. I am grateful for the help you've offered.

Relays it is then.

Okay, my next questions are:
1. Where do I get them?
2. What do I ask for?
3. How do I connect them up?
4. How would I connect them up with the regular filament bulbs as suggested?

Thank you so much all of you,

Chris

 

[Space cat]

The wiring isn't particularly difficult but ---

1. Where do I get them? 2. What do I ask for?

That's the hard part. I'll try to find you some answers but it might take a while. I'll be back.

 

[cpocal]

Ok Space Cat I'll look out for your reply.

Thanks again for your time.

 

[breezer]

Hi Space Cat, you haven't disappointed me. I am grateful for the help you've offered.

Relays it is then.

Okay, my next questions are:
1. Where do I get them?
2. What do I ask for?
3. How do I connect them up?
4. How would I connect them up with the regular filament bulbs as suggested?

Thank you so much all of you,

Chris

seem y previous post, i gavce links for realays

 

[Space cat]

Breezer beat me to it --

seem y previous post, i gavce links for realays

He did indeed, with this:

http://www.maplin.co.uk/Search.aspx?criteria=N14AW&DOY=14m9

but for the same price I would go for this:

http://www.maplin.co.uk/Module.aspx?ModuleNo=37519&&source=14&doy=14m9

or, for a couple of quid more, how about this monster:

http://www.maplin.co.uk/Module.aspx?ModuleNo=37495&&source=14&doy=14m9

Those web pages are a bit confusing. Make sure you get the 240V AC coil and the DIN mounting socket which, from what I can see, can also be screwed down. If you're going to put these outside you'll need a weatherproof box too but I think they would go better indoors along with the two small lights. No time left for wiring instructions tonight but watch this space.

 

[mr_chaela]

Why not apply a bit of Relay Logic and use just one relay - click diagram for full size image.
If PIR1 turns on it controls the lights directly, If PIR2 turns on it disconnects PIR1 and controls the lights, eliminating any loopback problem.

Just need a 2PDT relay.



hth

 

[breezer]

Why not apply a bit of Relay Logic and use just one relay -

because it won't work thats why.

when pir 2 turns off it will then put the supply back on turning the lights back on.

Ok reduce the time on pir 1 but that then means if pir1 is tripped it will not be on for as longas pir 2, and waht happens if someone walks past pir1 then past pir2?

Pir 2 will then "assume comand" and then when it turns the lights off it will repower pir1