Outdoor PIR sensor

xanadu

Anyone use the wide angle PIR sensor outdoors? https://www.parallax.com/product/28032

If so does it work well?

I've tried a couple other model that don't like being outside. It's for lighting so false triggers aren't an issue, but not triggering is.

I like that it has the light sensor built-in. In this http://simplytronics.com/docs/index.php?title=ST-00081 does the trigger sensitivity refer to motion or light level?

localroger

In daylight, even with the sensor in shade any PIR sensor will be swamped with radiation. PIR sensors don't work that well indoors, where the environment is much more stable. Probably better to see if some other sensor technology will work for you.

Phil Pilgrim (PhiPi)

Something like this might be a better choice -- and easier to seal against the environment.

-Phil

xanadu

I will try out the x-band sensor. I'm controlling some outdoor LED stips with a Prop Protoboard and RF remote.

I think I might try this for ambient light; https://www.parallax.com/product/28091 (UV light sensor) any objections?

I like the UV light sensor because it is less likely to trigger from the LED light strip being on at night. I'm guessing the output value won't change as much or at all with ambient temperature.

I would do the TSL235R Light-to-freq but I don't have 6V to power it.

xanadu

Another option would be to skip the ambient light sensor and use an RTC https://www.parallax.com/product/29125

I would need to code date provisions for sunset and sunrise. Decisions decisions....

xanadu

The X-Band works great! As mentioned, it works through an exterior wall and siding. No need to wait until dark to test it! Sweet.

I'm still wondering how those super cheap outdoor motion lights have really good results with PIR. I guess the hobby stuff isn't geared for outdoor use, which makes sense.

erco

xanadu wrote: »

I'm still wondering how those super cheap outdoor motion lights have really good results with PIR. I guess the hobby stuff isn't geared for outdoor use, which makes sense.

Interesting. I haven't tested any PIRs extensively. I have bench tested some of these cheapie units and been amazed: https://www.ebay.com/itm/174193834954

For under a buck, you get the PIR sensor plus an adjustable timer circuit. Some units (not these apparently) also have a photocell to shut down in daylight, much like the super cheap outdoor motion lights you mentioned. Crazy cheap stuff.

hatallica

xanadu wrote: »

I'm still wondering how those super cheap outdoor motion lights have really good results with PIR. I guess the hobby stuff isn't geared for outdoor use, which makes sense.

It depends on how you define "really good". I have a small bin of the ones that Erco mentions, that are leftover from my days of making Halloween props. For that purpose, they were surprisingly decent.

I would love to know if someone found super cheap outdoor PIR with good results. The only acceptable unit that I have found is RAB STL360, and it is far from cheap.

Tracy Allen

I used PIR sensors to count bats, their activity as they flew in and out of their roosts, caves or old buildings. The sensor itself was the a common type, with two pyroelectric elements hooked up in series opposition, so as to cancel out ambient changes and instead respond to differential motion lensed onto first one element and then the other. The optics were specialized lenses from fresneltech.com, chosen to focus far IR from a single zone line of sight, as opposed to the wide angle response of the #28032. The circuit had to be built up from scratch, so I had to observe the raw signal from the sensor in order to set the sensitivity and the signal processing.

Sealing it for use outdoors was not so much of a problem with the lens glued to a sealed box. Like motion detectors for lighting control, it only had to be active starting at dusk or nightfall. Inhibited in daylight. During the day, exposed surfaces "seen" by the sensors were just too hot and clouds or other effects caused large signal swings.

Characteristics of the signals can help for identification. There is a definite range of frequency peak response for the sensor elements, around 10Hz. For the bats crossing a line, the cylindrical lens was the most useful, and the response was a biphasic pulse. Even so, bats in large numbers could easily make a mess of a signal. In lighting or security applications, the lenses are most often arrays of small lenses, so a person moving through the field of view creates a series pulses in the electronics.

hatallica

You jinxed me. After reading your response above and your 25kHz rabid-bat-annoyer, I was visited by this little fellow.

Sidebar - AZ Fish & Game Department talked me into letting it hang out, in case it was lost vs dangerous. It was gone within an hour. Perhaps the bat is also biphasic - simultaneously solid and vapor?

Tracy Allen

Just plain tuckered out, social distancing for a while. Life is tough hanging out with a million or so BFFs!