IR motion sensor
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From: Jasen Betts on 25 Nov 2008 04:58 On 2008-11-24, raphaele.thevenin(a)gmail.com <raphaele.thevenin(a)gmail.com> wrote: >> Special Fresnel lenses tend to cost $5000 for tooling, unfortunately. I >> don't know of anyone who uses cylindrical Fresnel lenses at any wavelength. could you use a reflector instead? cylindrical reflectors are easy to make :)
From: RFI-EMI-GUY on 25 Nov 2008 16:29 raphaele.thevenin(a)gmail.com wrote: > On Nov 6, 4:25 pm, Phil Hobbs <pcdhSpamMeSensel...(a)electrooptical.net> > wrote: >> raphaele.theve...(a)gmail.com wrote: >>> Hello, >>> I am trying to build a special IR motion sensor, I need a one pixel >>> pyroelectric sensor and a focusing component for IR radiation. For the >>> pyroelectric device I found the component SSAC10-11 from Nicera. I was >>> wondering if someone knew if they had any competitors that would sell >>> the same component so that I could compare them. I was also wondering >>> if anyone would know where I could find a cylindrical lens focusing IR >>> radiation onto the pyroelectric component? (I only need a >>> unidimensional focusing). >>> Thanks a lot for your help! >>> Raphaele >> A good place to start is to rip apart a porch light sensor, and have a >> good look at how it works--it's quite clever. Lenses for the thermal IR >> are either (a) big hunks of silicon or germanium that cost $4000, or (b) >> Fresnel lenses made of high-density polyethylene (as used in bleach >> bottles) that cost $0.03. For one pixel you're definitely trending >> towards the HDPE end of things. >> >> Special Fresnel lenses tend to cost $5000 for tooling, unfortunately. I >> don't know of anyone who uses cylindrical Fresnel lenses at any wavelength. >> >> If your requirements aren't too stringent, you can probably use the >> segments of the fancy Fresnel lens in the porch light to do what you need. >> >> Cheers, >> >> Phil Hobbs > > Thank you! > I will look this up. I am indeed having issues with the fact that > these lenses are really expensive! > I will take a porch light and rip it apart. > Thanks for your advice. > > Raphaele Remember that the focal length for IR is somewhat longer than for visual spectrum so you have to adjust the focal plane for maximum IR focus. -- Joe Leikhim K4SAT "The RFI-EMI-GUY"� "Treason doth never prosper: what's the reason? For if it prosper, none dare call it treason." "Follow The Money" ;-P
From: JosephKK on 25 Nov 2008 23:07 On 25 Nov 2008 09:58:32 GMT, Jasen Betts <jasen(a)xnet.co.nz> wrote: >On 2008-11-24, raphaele.thevenin(a)gmail.com <raphaele.thevenin(a)gmail.com> wrote: > > >>> Special Fresnel lenses tend to cost $5000 for tooling, unfortunately. �I >>> don't know of anyone who uses cylindrical Fresnel lenses at any wavelength. > >could you use a reflector instead? cylindrical reflectors are easy to >make :) > > The only place i ever found any was navigation lights.
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