PIR Lights

[guest27]

Hi There all

Now I know frfom comments made some of you know one end of a 555 timer from a BC108 - or what ever are the in things now - shows how long ago it was I played with electronics.

Bought a couple of real cheap PIR LED lights (from Lidl) with the intention of putting them over the boy's doors.  Fine idea but they oly react if I put my hand above my head and wave.  Seems they have the range but not the angle.  I could try making some little angled blocks to mount them on - but that sounds like Roger's woodwork...  Other though was desoldering the detector and put it on flying leads and remount it pointing in the right direction at the front of the enclosure.  However on popping the thing open there are two options.  What liiks like a LED (IR?) which sits right out into the 'detector' window, and then a metal cased thingy with what looks like a window through the case - this is printed PIR on the case (could be a clue) but is sat right back on the board and is thus really shadowed by the detector window.  Do you think I would be right in guessing that I need to take this off, put some flying wires on it and mount it in a new window cut in the bottom of the unit?  Do you think I will also need to reposition the "LED" alongside it?

After all of that - just how long is a piece of string?

R

[Steve Lake]

Errrrm....well, yes and no!.....you are almost certainly right that the pir detector is mounted onto the board,
it may have an ldr (light dependant resistor) associated with it, to ensure the unit only comes on if it's dark. but more importantly, the plastic cover in front of the pir is a lense, and if you remove the lense or move the pir away from the lense you may well find that the unit will not operate or operate continuously, better to move the led(s) and keep the rest of the unit 'intacto' anyway, sound like fun....just the sort of thing we should all be doing these dark winter nights!

BC108's ? love 'em did you know the Nimrod (aircraft) had over 9000 of 'em (well it did in the 70's)
trebble 5 timers .... 400 in the apollo space craft!

wonderful bits of kit....... If windows vista was a billionth as reliable....it would be good!

[mini-thumper]

Clear 'LED' is the IR transmitter - they usually have a wide, but not very strong, angle of transmission, therefore the lens is used to focus the IR beam. The detector often looks similar to an LED but black, square, and with a dimple on one of its vertical faces. It sounds as if in your case its contained within a metal housing - can you get inside it?

Flying leads and general mucking are a very good idea. Best of luck.....

BB
PS I really like the 556 - two 555's in one package. Reminds me I must finish making those bike alarms I promised Alan Stringer!!!!!