I have a typ PIR sensor in a motion activated light that is automatically triggering. I have reconfigured my circuit to implement a 10k pull down which kept the sensor from triggering at all. I went from a 51k down to a 15k, but it is still triggering on its own. I have a 2.2k series resistor from PIR out pin also. I ordered these PIR sensors from Alibaba and was told that no jumper is provided or required. Can anyone give me an idea why this sensor seems to be so difficult to stabilize? I also have a '472' cap between signal and gnd on the pir.

 

Was it problematic from the very beginning or started behaving like this all in a sudden?

 

I've been using PIRs from Amazon that have the yellow jumper, for years. They have always worked just fine. Now I have a new PCB with added esp32 and mini-360 incorporated. I am also using these 'new' PIRs from Alibaba that do not have the typical yellow jumper on it. Those pins are just 3 solder pads. I have nothing jumped and was told by seller that jumping was not necessary. This auto-triggering issue started with the new PCB and new PIRs. I did another test by covering the Fresnel lens with electrical tape. It still auto-triggers immediately.

 

hi john,
Post a link to the Alibaba advert, so that we can identify the PIR type.
Show where you added the pull down Resistors.
E

 

I've been using PIRs from Amazon that have the yellow jumper, for years. They have always worked just fine. Now I have a new PCB with added esp32 and mini-360 incorporated. I am also using these 'new' PIRs from Alibaba that do not have the typical yellow jumper on it. Those pins are just 3 solder pads. I have nothing jumped and was told by seller that jumping was not necessary. This auto-triggering issue started with the new PCB and new PIRs. I did another test by covering the Fresnel lens with electrical tape. It still auto-triggers immediately.

Hello, since I cannot see any pic or datasheet, I am asking. In cheap PIR sensors like HCSR501, there are two variable resistors that need to be adjusted to set timing and sensitivity. Are there any such things in your product. Also, I think you should contact your seller ASAP if you already have not. They can tell if you're missing something or the product is DOA.

 

If the sensor system is triggering without any external signals, such as motion varying the sensor output, THEN THEFAULT IS EITHER NOISE OR COMPONENT DRIFT.
Since the TS did not answer that very basic question posed in post #2, I see no reason to continue with this.
REALLY, that was an important question in post #2, and the answer should not be difficult to provide.

Is there possibly a language issue and a translator problem??

 

There is a very simple question posed in post #2, and the answer is rather important, as I see it. Really, that makes a big difference in where we would look for the problem.