IR motion sensor

Nov 06, 2008 9 Replies
R

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


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P

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

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P

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

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J

For the lenses: http://www.fresneltech.com/ for the sensors: http://www.murata.com/catalog/s21e.pdf http://www.fuji-piezo.com/prodpyro.htm or: http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GFRC,GFRC:2006-50,GFRC:en&q=pyroelectric+sensors JF
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J

And: http://www.heimannsensor.com/DataPYR.htm I\'ve used their stuff and it works nicely. JF
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R

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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

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R

GFR...

Ok, I am looking them up! Thank you for your help!

Raphaele

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J

could you use a reflector instead? cylindrical reflectors are easy to make :)

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R

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
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J

The only place i ever found any was navigation lights.

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