One for Electronics boffs

Ok, my brother is an 'artist'. he has agreed to create an intallation and has asked me to help.

Basically there is a lake, which we are going to be putting a fountain in.
then there will be 7 PIR sensors place around the lake.
What we need is a way for the sensors to Turn the fountain OFF when a pir is triggered by somebody walking past. once they have gone the fountain needs to come back ON.

i have found this:
THIS

which i think should work, but it switches ON when we need it to switch off.
My question is: how could we get it to switch off rather than on? i was thinking about using a relay.

Or is there a better way?

One of my HiFi customers has a frog that squirts water every time a heron comes near or anything else for that matter. What about reversing the wiring to get the reverse effect. Or is thatcompletely stupid.

cant imagine reversing the wiring would make a difference. surely its the switch in the pir that dictates what happens.

the light obviously turns on when the sensor triggers a switch. why not see if an off switch can be made????? or found

A normally closed Relay should work. I was looking for some info on th e PIR to check but couldn't find it

Some PIR sensors will be provided with normally open and normally closed contacts, just use the normally closed contact. Alternatively wire the pir output to a single pole changeover relay (spco) and use the normally closed contact of the relay.

i did think i could get Closed contact pirs.
was also thinking about using one relay per pir, but having one relay would be better.
well we are having a nice driving holiday to berlin out of it!

If you have one relay per pir you can run the feed to the pump in series through all 7 relay normally closed contacts. If you don't want to run mains throughout the system, use low voltage dc and relay coils colis to match, then wire series contacts to one more relay coil. last relay will switch mains. 8 relays in total costing ? £40. Much safer using lovo with water around!.

Use the item you have from the rs link above.As some have mensioned use a normally closed relay.

Pirs>>>>contol unit>>>>control unit output>>>>contactor/relay coil.

Wire your fountain through the NC contact on the contactor/relay.