PIR sensor sensitivity problem / false output

[arisu1love]

Hi,
Recently i bought a PIR sensor from cytron, and i tried to test it today. the problem is, i find that the sensor is too sensitive/gives false output. for example, when there is no motion detected, output high is still detected on the output pin. can anyone help me with this problem?

thanks!

[shahrul]

Last time I use PIR also get same problem. Video.
It suppose to trigger when there is motion detector. But sometimes, when not moving also it's trigger. I think it's need very quit enviroment.

[yonghui]

hi,

i never use the sensor. anyway to debounce the false trigger by using calculation of the length (in term of time) of the high output from the PIR sensor?



yh

[sich]

Yes, this PIR sensor is quite sensitive. Anyway, the result is still accurate as far as i'm using it for my project. I set it to Retrigger mode (forget what's the default mode) where the output remains HIGH when the sensor senses movement repeatedly. Then i adjusted the variable resistor to certain delay time that suit my application too. So in between the delay time, my system will read HIGH until the signal goes LOW again.

[arisu1love]

Thank you for your replies. The default mode is retrigger mode, so I did not change that too, because it is soldered with wire into place, I did not tamper with it. I find it gives a 010100010101 output (i use to light led for testing) when there is motion. Not quite what I expected because I expected 11111111 when there is occupant. The delay time setting which is available on the sensor, may i know what is the purpose of it, and how exactly to tune it to suit my application? My application is for home automation where devices are turned on/off with when occupants are present/not present.

[shiyan]

I use that sensor before too, sometime did give some weird response. But I use filter which is to sample more time before the program make decision, I can still accept it