text: is there anyway to trip a pir motion detector before i get to it?  like blasting it somehow with ir radiation? so if i'm driving down a road and there is a passive ir sensor, is there any way to activate that sensor before i get.  will shining an infrared led work?  or anything else? infared light will only work if it is an infared censor. it could be radar or pocibly even metal detection(if it isnt measuring speed). dont forget that you would need a very very bright infared light, a little led wont cut it. remember that the sun shines infared light so your light would have to be strong enough to confuse the censor.