Declan wrote: > Can someone point me at decent reading about infared? I am looking at a > project involving infared detection, sunlight, and people. Suffice it to > say this is someone else's idea about which I am instructed not to be > specific. > > In this application, I ideally want to sense people with complete > sunlight rejection using infared. The 2 standard techniques - Emitter > Pulsing, and movement detection as used in home alarm PIR detectors are > unsuitable for various reasons. False positives are basically > unavoidable, and I can cope with that. I want to minimize it, however. > I don't want false negatives, however. > > Let me be more clear: I am not worried about the orb of the sun creating > a false positive. I AM worried about not picking up something (i.e. a > false negative) at 30 degrees right or left of it.
Hi Declan, Although you gave a lot of details, something is still missing. When you detect the subject emitting IR, can it be that the sun is seen in allmost the same direction, so causing a blinding effect? Is the subject, you want to detect, something technical, on which you can choose a modulation frequency (perhaps you want not to answer this question, which I will understand very well). Can the space angle which is covered by the subject be a discriminating feature? Can distance be a dicriminating feature? When you use 2 detectors, you have 3-dim information. All these questions depend havily on what it is supposed to cost. Regards, Harry -- Author: H.C. Croon INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
