Advice Requested: Where to place this exterior motion sensor

I am considering buying this http://resolutionproducts.com/products/intrusion-sensors/optex-outdoor-pir/

I do not want it to trigger our alarm, but merely “announce” if someone is out there (see picture).

The most important thing I am trying to do is to secure the door pictured, but I am not sure where to mount this senor. The wall corner before the door is a 45 degree and not a 90. The main problem is that spotlight that comes on all night that I fear will interfere with the PIR?

Do you think the LED spotlight will interfere with PIR of the exterior motion?

Where would you mount the sensor? Ideally it would capture movement around that door and as far back down the corridor as possible.

I could mount it on the retaining wall but then its exposed to the elements all the time (even though its an outdoor sensor)

Are the accessories I should consider to get the sensor “off the wall”?

Thanks in advance for your suggestions

Light should not interfere with the IR infrared) sensor. Your motion sensor looks for body heat and senses the heats movement. Visible light has a lower wavelength than infrared (heat). With the bulbs being LED, the bulb itself should not get hot enough, quick enough, to trigger it either. Especially since its pet immune sensor, a small amount of heat from a bulb should not trigger it, even if it was going to in the first place. I can’t GUARANTEE this, but if it’s a good quality sensor, it should not be triggered by it. So, I wouldn’t factor in your lighting when locating a place to install the sensor.

As for the placement, if I was doing the same thing you are, I would mount a small piece of wood to the top of your overhang and put the sensor on that small block of wood to point directly down the corridor

Also keep in mind on the specifications, it says it is good for a maximum up to five meters, when mounting it.

The biggest limitation will be the effective range of the sensor. Looking at the image, you are likely best served by mounting a motion detector facing the opposite direction with the door within the range of the sensor.

Always mount the device based on the manufacturer instruction. Height is typically very important when mounting a motion detector. The RE253 manual I found stated 7.5 feet for mounting height. It looks like the retaining wall may not be that tall, but hard to tell.