Where can I purchase and Fresnel lens for a PIR detector. I am trying to improve the range of an X10 Hawkeye motion detector(MS12A). Ray ----- Original Message ----- From: "Jinx" To: Sent: Wednesday, August 22, 2001 4:38 AM Subject: Re: [OT] Crocking Frog, People sensor > > Does anyone have info on connecting a PIR sensor > > to a PIC?? This would be great for devices or > > lighting systems that activate when you enter > > the room, etc. A great use for a PIC. :o) > > -Roman > > I use this for a battery-operated indoor application. It has very > low power requirements (140uA @ 5V). The 5V supply comes > from a PIC pin which turns the PIR off with a logic "0" after the > PIR has woken the PIC from sleep. > > The sensors are from Murata. A proper Fresnel lens is essential - > the response to PIR in the low Hz is far better than with no lens > and the range (7-8 metres) is around 10 times greater. There > are more sophisticated circuits in security lights, based on quad > amps like the LM324. I've no need for that as occasional false > triggering is no big disadvantage in my application, but there > are ultra-low power around that could replace the standard type > > One improvement I'd like to make to this circuit is a self-settling > function. Replacing the trimpot with a fixed RC filter that responds > quickly to (relatively) fast wave bumps such as caused by a body > but ignores drafts or increasing/decreasing sunlight > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.