P.I.R.

The widest angle I have seen is 180deg (other than, of course, the

360deg downward looking types). Maplins and rs components have them. My favourites are from bull electrical at around 25GBP for five.

You /should/ be able to simply stick two of them up, overlapping, and common the switched wire ( mine have the output relay driven). But "mileage may vary" - so check that yours use a relay too.

The height won't be a problem as they (the bull ones) are very adjustable and can be pointed down to minimise the blind area.

I have used lots of them and am very pleased with them.. good false alarm rejection and good sensitivity adjustment.

-- Sue

Thankyou very much for your reply Sue,

The reason that I want the PIR to be fixed at 5M is that sometimes a rubbish lorry is parked right in front of the post and therefore require them to be at around 5m hight to cover behind the lorry. I also require them to have a coverage of around 20M.

Any Ideas?

Regards Dafydd

Well, the bull ones certainly work out to a range of >10m - which is hell of a distance for reliable pir, IMHO. They quote 15m (which is about the max you will find) - but it really depends on ambient conditions and the "fingers" will be quite wide at that sort of distance for that sort of angular coverage. It may sense a running hot adult but not a strolling cold child..

At 20m'ish sort of distances, I would probably be going for break beam rather than pir. You can cover the whole length of a field with one of those (we have rustlers in Devon, UK,as well as over the pond..)

Multiple sensors are often a lot easier to set up than just one..

You may be able to get longer range by using your own lens but it is going to *decrease* the angular coverage.

With a 5m high sensor, angled for maximum range, you are going to have quite large blind spots near the base. Multiple sensors can fix that very easily.

Hi,

Very much appreciate if you can tell me what does a PIR stand for or any other short form to be highlighted?

Sorry, not all things came the same.

Tks

magic

Passive Infra Red.

-- Sue

tks sue

tks

magic

tks sue

tks

magic