PIR based motion sensor.

[riponsp]

I have made a PIR based motion sensor with a simple OP amp and a 555 timer IC. It's very low cost and simple. When it found some motion, it'll trigger for a certain time. after that it'll automatically back to it's normal position.

[bigtoy]

I saw an interesting project on the web some time ago (need to google to find it again) which used 2 PIR sensors to detect cats jumping up on the kitchen counter. Due to PIRs having a very wide viewing angle, they put one PIR on each edge of the counter. Only when both PIRs were triggered (ie, the cat was in the overlapping field of the two PIRs) did it set off a noisemaker to scare off the cat.

[solutions]

One of these on the kitchen counter works well....AND....it doesn't need batteries



K.I.S.S.

[riponsp]

solutions give the best solution . No battery is needed, haha. I use this PIR sensor for Bathroom's light, Loan's light etc. No need to turn ON/OFF switch manually...