UPDATE: Replaced my PIR-Sensor with a Doppler Microwave Sensor.

uros76

@Lipax said in UPDATE: Replaced my PIR-Sensor with a Doppler Microwave Sensor.:

hello,
i tried this with the microwave sensor, but im out of ideas. i get wrong positives every minute. (i check every 5 sec).
i added also the ferrite, tried another raspberry, different of these sensors (bought a 5 pack) and placed it in a different room. anyone got any ideas what else i could try?
or maybe similar microwave sensors i could try?

any help would be great, tyvm

Did you try and limit the range as described in beginning of this thread? For me option 2 helped to limit oversensitivity.

Lipax

@uros76
the range is not the problem. i get positives when nothing is moving near it

uros76

@Lipax this sensor is very sensitive and catches any movement 360 around from several meters away. I had same problem… If you don’t dial down the sensitivity-range you will keep getting false positives.

kayakbabe

@Lipax try dialing down the sensitivity, it’s probably picking up dust or something small you can’t see.

Lipax

thanks for the help, but i doubt its some kind of movement since its exactly every minute. i tried a different room and its the same.

sdetweil

@Lipax please don’t submit duplicate posts…

all users with reputation below 2 have their posts reviewed… this eliminates all the porn, advertising and trash posts from the forum.

it just takes time for (me) to get to review the posts…

uros76

Can you share your python code? Perhaps there’s something there

Lipax

@sdetweil sry about that

@uros76 i hope thats not the problem

import RPi.GPIO as GPIO
import time
import datetime

switch=11


GPIO.setmode(GPIO.BOARD)
GPIO.setup(switch, GPIO.IN)




try:
    while True:
        if GPIO.input(switch) == 1:
            now = datetime.datetime.now()
            print(now.strftime("%Y-%m-%d %H:%M:%S"), "something")
            
        time.sleep(5)
        
        
except KeyboardInterrupt:
    print("Bye Bye")
finally:
    GPIO.cleanup()

thanks for the help

uros76

@Lipax try different gpio pin, like a pin 18 which is a GPIO 5. It’s default set to input function. Don’t forget to adjust the python code, change switch to 18.

You might check the GPIO 0 (your pin 11) if it is set to input. Use command: raspi-gpio get 0 or raspi-gpio get to check all GPIO’s.

Also, use a multimeter to measure the voltage coming out from sensor. It should be around 3.3V for few seconds when sensing detected. This way you can monitor if actual detection / voltage is coming from sensor.

Lipax

@uros76
i forget to mention i already changed the pin, i first tried pin 7 before

according to pinout.xyz my pin 11 is gpio 17

GPIO 17: level=0 fsel=0 func=INPUT

thank you very much for helping me, i dont have a multi meter but ill ask my father to do that. u think its not the sensor sending the signal? maybe it picks up something with the wire along the way? i dont have a engineering background.

uros76

@Lipax you need to be sure that sensor is not the cause.
Measuring it’s sensing, output voltage and duration is a good way of confirming if sensor works ok.

Lipax

it took a long time but i tested the voltage, i can upload a video somewhere if u want. the wrong positive and the regular ones look the same for me. it kinda spikes to ~5v and then instantly goes to 3.3 and stabilizes

uros76

@Lipax there you go, nothing wrong with the software code. It’s the PIR sensor giving false positives. Nothing you can really do about that. Perhaps a different brand/quality of PIR sensor if it will help but I doubt.

As mentioned before, due to exact same problem I gave up on PIR sensor completely and moved to the microwave. This works for me now over 3 years. without false positives.

Lipax

@uros76 ty ill maybe try to find another microwave sensor. pir i find really ugly try to stay away from them. really sad i didnt get the microwave sensor working. thanks for the help