Cytron Technical Forum

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!

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.

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

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.

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.

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