Ok, I have used a Visonic PIR sensor (just a normal indoor wireless one) placed in a water proof tube with a small whole in it nailed to a tree. A waterproof bird box would be a good choice. The point is you have to reduce the field of vision to a tunnel. You then need to make sure an object prevents it from seeing too far. I have an Iron gate with a line of conifers opposite. Any one climbing the gate will go straight through the field of view of the PIR. Cats wonít climb the gate as they can go through it as do foxes. The trees face is away from the sun so no false alarms. Anyway chimes in the day don't bother me; it's late at night to the early hours that are important. The zone is chime only so it never sets the alarm off. Just use trial and error to get the setup right. The main problem with the visonic PIR is that they seem to switch themselves off after a number of alarms presumably to save power. A real pain when testing the system. The PIR was outside all through the winter without issue. A check inside shows no sign of damp damage. Obviously there is a chance indoor PIRs could get wrecked but like I say my wired PIR has been outside for 4 years and is as good as new. At £3 I'll replace it if it goes. I brought the Visonic one it after about 9 months because I didn't really need it. One was enough.

No X10 is required for chiming unless you need a remote chime. Chime will work on any zone regardless of how it is triggered so PIR is fine. The problem with chime is will you hear it at night. In my case I bought the visonic two way remote keypad because it allows me to control the alarm from my bed and receives the chime from the base unit. This cost £88 pounds but it does offer full remote control.

Why do you want a chime to go off if you put the light on?

You can use X10 but you need the X10 controller. You will then need three X10 appliance switches (one for each flood light. Won't one be enough?) and if you can't use the built-in chime you could use the X10 dog bark. You can then program the unit to send an X10 command to switch on the lights. Personally I wouldn't bother with X10 controlling the flood lights because it sometimes fails so it might not turn the lights off. 1500W left on all night might cost a bit. I use normal PIR that comes with the lights. Ok this goes off a bit more but does that matter. The PIR for intruders is separate and the two systems are independent. X10 could be used but it would be better with a bespoke application to do clever things. I use my Java app so I can say things like. If the lights have been on for 10 minutes between 10pm and 7.00am say then turn them off. You can by clever apps but I donít use them so canít comment.

Best of luck.