Hi Shahzad & others

2,3 years ago, I was doing similar stuff. The best place for info is the home page of Nippon Ceramics i.e. www.nicer.com where you'll find what you need.

Also the Fresnel Lens is a costly affair, its made only by Fresnel Technologies Inc of the USA. Look up the home page of www.fresneltech.com(The plastic window is made of special polycarbonate material with very accurately formed contours.

The electronics is fairly simple. Its just like wiring up to a comparator. However without the fresnel window a sufficiently useful PIR detector cannot be made. which Is why I gave up trying. Anyway best of luck to you.

Raj S. Iyer