PIR am312

[gohan]

maybe removing the smaller lens could improve the sensor?

[NeverDie]

I did. What you see is just the holder that the regular lens snaps onto.

[wallyllama]

Here is my version of a holder. It is for the bigger PIR. But it holds a dhtXX, ds18b20, and a light sensor as well.

[NeverDie]

Nice!

On my holder, the sensor depth is presumably wrong from a focusing point of view--at least if the SR501 is a proper guide for how it should be done. The sensor should really be deeper into the cavity. I suppose that alone might make a meaningful improvement. Alas, I think that may call for mounting the sensor element onto a PCB, so that it sits flush on top.

[NeverDie]

@Nca78
Have you worked out the dimensions for the four holes that the SR501 lens fits into? I'm guessing so, given your shield above. I could of course try measuring the distances with a micrometer and the hole diameters with some gauged wire, but it might take a few PCB iterations to get it right. However, if you know the exact hole diameter and distance between the holes, it would be helpful if you shared that info so that we can get cracking on making custom PCB's that incorporate it.

[scalz]

@NeverDie
This is what i'm using here for my boards, and fits ok

[Nca78]

Searched a bit and found this. Guess my measurements were a bit off, hope it will fit with 17.4 and a bit over 22...
I should have searched while doing the PCB :D

Real measurements are 17.5mm and 23.3-1.45 = 21.85

[NeverDie]

I ran a banggood PIR sensor off my 3.3v boosted 10F supercap solar node last night and, as you would expect, the extra load was so low that it's practically a rounding error. :) These PIR's would have no problem being powered for days from a supercap.

@Nca78 I guess what you're calling "sensibility" on your board above is another name for sensitivity? i.e. you figured out how to adjust the sensitivity of the PIR detector? That's something not obviously accessible on the banggood PIR's, as they don't seem to come with a sensitivity adjustment. If you've already figured out how to adjust the sensitivity, would you mind sharing the schematic? It might help us avoid re-inventing the wheel if we were to follow the path you've already blazed.

[Nca78]

@NeverDie haha yes it's the sensitivity sorry sometimes my English fails and I mix with French words :D
I will fix on the PCB.

This can be set only on am612, I bought the sensor only (no breakout board) on AliExpress. It has 6 pins for the extra settings instead of the 3 of the am312.

[NeverDie]

@Nca78 said in PIR am312:

@NeverDie haha yes it's the sensitivity sorry sometimes my English fails and I mix with French words :D
I will fix on the PCB.

This can be set only on am612, I bought the sensor only (no breakout board) on AliExpress. It has 6 pins for the extra settings instead of the 3 of the am312.

Good to know. Does it draw the same or comparable amount of current as the am312? If so, you've just saved me from ordering the wrong sensor! :)

[Nca78]

@NeverDie said in PIR am312:

Good to know. Does it draw the same or comparable amount of current as the am312? If so, you've just saved me from ordering the wrong sensor! :)

The datasheets are similar for everything that is not related to the extra pins of course: same electrical specs, same detection profile, ... My guess is it's the same PIR sensor but on am312 some of the settings are just hardwired inside the "can".

[NeverDie]

Cool! I'm going to follow your lead and order some of the am612's then. Thanks for the heads up!

[scalz]

sensitivity can be adapted in sw

[Nca78]

@scalz said in PIR am312:

sensitivity can be adapted in sw

For am312 ? How would you do that when all you have are Vcc, GND and signal pin ?

[NeverDie]

I ordered these:
https://www.aliexpress.com/item/10pcs-AM612-DIP6-human-infrared-sensor-module-pyroelectric-infrared-sensors-Sensor/32604041429.html?spm=2114.01010208.3.15.vPmcAS&ws_ab_test=searchweb0_0,searchweb201602_5_10152_10065_10151_10130_10068_5010014_10136_10157_10137_10060_10138_10155_10062_10156_437_10154_10056_10055_10054_10059_303_100031_10099_10103_10102_10096_5170015_10147_10052_10053_10107_10050_10142_10051_5190015_10084_10083_10119_10080_10082_10081_10178_10110_519_10111_10112_10113_10114_10037_10183_10182_10185_10033_10032_10078_10079_10077_10073_10123_10120_142,searchweb201603_4,ppcSwitch_4&btsid=99796fa2-b6d9-451b-89ee-c690f3ec0542&algo_expid=357f8654-d7b8-423c-8af7-8a8a924a49a5-2&algo_pvid=357f8654-d7b8-423c-8af7-8a8a924a49a5

[NeverDie]

Not sure if this is the same as the SR501 lens. Really hard to tell from the photo:
https://www.aliexpress.com/item-img/5Pcs-Lot-PIR-human-body-infrared-sensor-lens-Mini-lens-high-quality/32563535500.html?spm=2114.10010108.1000017.1.oavh25
If anyone finds a confirmed source for SR501 lenses, please post.

[Nca78]

SR501 lens is referenced as 8002-2. But it seems all those big fresnel lenses with 4 pins are the same, I suppose one original maker and a bunch of copycats.

[scalz]

@Nca78 said in PIR am312:

@scalz said in PIR am312:

sensitivity can be adapted in sw

For am312 ? How would you do that when all you have are Vcc, GND and signal pin ?

with timers. but, it's a bit more power hungry if using simple 8bits mcu, not a problem with more powerful mcus like ARM etc. which have more low power features.

[Nca78]

@scalz said in PIR am312:

with timers. but, it's a bit more power hungry if using simple 8bits mcu, not a problem with more powerful mcus like ARM etc. which have more low power features.

Still not getting it :)
This sounds more like a solution to manage "on" time when triggered but I don't get how this could make your sensor detect at 5m instead of 3m ?

[scalz]

@Nca78
oki. lol i messed a bit with terms too :blush: yes for "on" time.
for 5m instead of 3m, this will depends of sensor quality and its lens. I think in datasheet they give a max range for an ideal lens, or that wouldn't make sense to get long range with a crappy lens..