[solved]read PIR sensor on orange pi pc plus

wwwlu · Published in 2017-1-20 19:24:56

Edited by wwwlu at 2017-2-24 17:54

I have installed the following:
https://github.com/duxingkei33/orangepi_PC_gpio_pyH3
I can succesfully make a led blink.
But I can't read the value of a PIR sensor (HC-SR501 )
It returns 1 during 3 seconds then 0 for another 3 seconds and loop.
I tested the sensor on a arduino and it works fine
here's my code:
from time import sleep
from pyA20.gpio import gpio
from pyA20.gpio import port
mq135 = port.PA12
gpio.init()
gpio.setcfg(mq135, gpio.INPUT)
try:
while True:
      state = gpio.input(mq135)
      sleep(0.2)
      print " %d"%state
except KeyboardInterrupt:
print ("Goodbye.")

shooreg · Published in 2017-1-20 21:54:39

have you tried to read values from corresponding file in sysfs directly, when sensor is attached?

wwwlu · Published in 2017-1-20 22:08:42

no shooreg, how can I do that ?

shooreg · Published in 2017-1-20 22:35:24

Try like described here.
The GPIO pin states are reflected to text files in sysfs, usually files are named equal to pin naming. These text files contain 0 or 1 for a high or low level of corresponding pin.
Very useful for debug purposes.

shooreg · Published in 2017-1-20 22:37:50

And besides that, these files are not read-only, so you can change the state of GPIO pin directly from the shell, just using something like "echo 1 > /sys/class/gpio_sw/PA2"

shooreg · Published in 2017-1-20 22:47:41

By the way, yor sensor has 2 work modes (H and L) and 2 regulators (sensivity and impulse length)
What you described in your post is a normal operation in mode L with impulse length set for 3 sec.
So, actually, looks like you have everything working correctly.

wwwlu · Published in 2017-1-20 23:44:09

Edited by wwwlu at 2017-1-21 00:45

I checked in /sys/class/gpio_sw/ and there is no PA12
So I changed for PA6 but I still get the same issue
I have no problem to set a value (using python) for a pin but what I want is to read the value.
I am supposed to receive 0 if I don't move in front of the sensor and 1 if i do. That's the normal behavior on Arduino
The Trigger Mode is set to L but that does not change the problem. Even if no motion is detected the sensor send 1 every 3 seconds

shooreg · Published in 2017-1-25 15:52:48

OK, try without sensor - simulate logical 0 and 1 on GPIO pin you selected by pulling it to GND and 3.3V respectively. And check if your software reads it correctly.

wwwlu · Published in 2017-2-16 01:21:54

thanks shooreg, I changed the jumper of the sensor and give it time to stabilise (15 seconds) and it works fine now