On 8/29/06, Peter Todd wrote: > On Sun, Aug 27, 2006 at 04:35:58PM -0400, David VanHorn wrote: > > > > > > > > > There's an idea for you Peter, take a traditional clock and replace the > > > motor with a stepper. Have it work normally keeping time but > > > periodically "go nuts" backwards, fast forward etc, then correct itself > > > and behave for a random period.That might sell.. > > > :) D > > > > > > A PIR detector could be used to detect when you were really in front of it > > "watching" so as to prevent the behaviour during those times, but allow it > > to go nuts when nobody's all that close to it. > > That's a pretty cool idea! Actually a friend of mine made an art peice > using a similar concept, she built various types of playground > equipment, see-saw, swing and one of those merry-go-round things, and > all made them activate and move while you were busy reading her artists > statement. They stopped the second you moved away to look at the work. > > In practice of course, standing near the work, but looking away, still > kept the PIR sensor going... So... Any PIR sensor is based on a fresnel lense. There are two or three types of lenses every of them specific for the PIR destination. there are "courtain" lenses, "gallery" lenses and "volumetric" lenses. 1. Is very easy to modify any of these by keeping active just the part of the lense which is in front of the art masterpiece. There are three rows of fresnel areas on any PIR. Use a piece of paper cutted in the center and put it inside the PIR package on the lense area so only one fresnel area should be transparent for the PIR sensor. 2. The other choice is to modify the gain of the PIR amplifier so the sensitivity will decrease but the whole sensed area remains active. In both suggested versions (better combine one and two) you'll be able to create a PIR sensor with active area of about 2 meters (lowest row of fresnel, volumetric lense) and just one direction of sensing. greetings, Vasile > > How would you go about detecting the someone's gaze? > > Personally I'd rig up a digital camera, with "eye-detecting" software, > but surely there are better ways... > > -- > http://www.petertodd.ca > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist