5 Pack HC-SR501 Pir Motion IR Sensor Body Module Infrared for Arduino

Hooked the VCC and ground to a 12v A/C adapter and it worked perfect. The 3.3v "trigger" pin (the "OUT") even had enough juice to directly power a red LED (tho a little dimmer than normal). Very wide sensitivity pattern. Tho description says "< 100 degrees" I thought it was greater than 120. At default sensitivity it would trigger easily from 8-10' away. I never adjusted it as that was the perfect distance for my needs. Holding it with the sensor "dome" facing down and the adjusting (orange) "screws" facing you, the left one is the sensitivity, the right is the duration that the OUT pin will stay "on" (i.e. hold at 3.3v). Minimum seems to be around 4 seconds.

These are useless as motion detectors due to the false reports. Yes I tried the pF capacitor from Signal to Ground and I shortened the signal wire. It did reduce the false motions but they still happen few minutes. Unfortunately I can't send them back due to adding the capacitor to the circuit. I would not recommend these to anyone. I will try to keep fussing with them. I am trying now on a Wemos D1 Mini with less than 1 cm of signal wire from PIR to data pin. UPDATE: Still bad on the wemos with <1 cm wire. Tried pull up resistor - no effect. Increased and decreased capacitor size - no effect. I've ordered a different type. Hope they work.

I first bought a pre-built 'smart' light switch with a motion sensor that was WAY too sensitive and couldn't be adjusted. I decided to go the DIY route and bought these. I connected one to a NodeMCU, which I set up with Home Assistant using MQTT (along with a simple 'smart' switch sans motion sensor). It's awesome, gives me so much more control and cheaper. I do get some false-positives, but not nearly as much as with the pre-built unit. I suspect it's due to being in the garage and the sensor picking up sunlight/shadows coming in through cracks in the garage door. Overall, very happy with the purchase.

Bought these for Halloween decoration triggering. They work well, but the overall design has it's limitations (doesn't matter what MFG). Super sensitive to ambient light, so works well in a darker/indirect light situation. Also only really sensitive in 1 plane/movement direction. So you may have to rotate it 90* as it's not a cone of sensitivity, more like a long oval in one plane.

These are great for turning the screen off and on, in my controller box.