On 20-Feb-12 23:42, David Duffy (AVD) wrote: > Has anyone here done much work with proximity sensors? I am looking to > trigger an event when someone stands in front of (or walks past) a > specific area in a retail environment. The sensing must be done from > one side only (no beam break methods). Sharp IR proximity sensors? Djula > > The sensing range would need to be approx 200mm - 1000mm (8" - 40"). > The horizontal detection width would need to be approx 500mm (20") at > end of the range I guess. There would be multiple sensors, spaced at > approx 600mm - 900mm (24" - 36") intervals. > > There is nowhere to mount the sensors apart from near the floor or > *maybe* on the wall higher up. Ideally the sensors need to stand up to > a bit of abuse from knocks and maybe a splash from a cleaners mop. > > Typical machinery proximity sensors would be easy to mount, but seem to > be mostly very short range. Ambient light can change somewhat so shadow > detection would not be suitable I suspect. > > I had thought about ultrasonic "range finders" (as used in robotics) but > they would probably interact when use this close together. They also > wouldn't stand up to the abuse they'd cop being mounted down low. > > I think typical PIRs are going to be too coarse, but maybe there are > better ones than what I've seen so far? > David... > --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .