I am using a couple of cheap ebay PIR motion sensors with the classic bubble dome. I think this dome is ugly and I would like to substitute a different lens cover. Here is an image of the device, the idea is that the opening at the top is to be a band of some material that won't inhibit the 3 motion sensors inside.
The bubble dome and other motion sensors use a semitransparent fresnel lens to gather IR light on the receiver, however it works quite well without the dome at all.
If possible, where can I order this same semitransparent fresnel lens in the long thin shape that I need? What other materials can I use that will not impact PIR sensors. Acrylic maybe?
LOL, actually I "always" start with a google image search to look for unknown devices.
Sometimes you need to scan through a number of sites, but that's life.