Scandinav21 Posted April 9, 2020 Share Posted April 9, 2020 Armbianmonitor: http://ix.io/2hls Hi everyone. I almost gave up while reading tons of forums:( I bought CO2 sensor MH-Z19 from aliexpress. As I figured out this sensor used by RPi without any problems. Manual I found here: https://www.circuits.dk/testing-mh-z19-ndir-co2-sensor-module/ I connected module as mentioned: Vin - 2 pin gpio GND - 9 pin Tx - 13 pin Rx - 11 pin Module was blinking when I powered on my OPi, but when I tried to send data to UART nothing happened. I got timeout. I tried to connect Tx and Rx (11 and 13 pin) by cable, then sent bytes and immediatley got answer, UART work, as I understood. I checked uart in armbian-config menu and all (1,2,3) was enabled. Orange PI PC Plus Linux orangepipcplus 5.4.30-sunxi #20.02.9 SMP Mon Apr 6 19:46:24 CEST 2020 armv7l GNU/Linux Can somebody help me, please? Spoiler import serial import time import subprocess import getrpimodel serial_dev = '/dev/ttyS2' stop_getty = 'sudo systemctl stop serial-getty@ttyS0.service' start_getty = 'sudo systemctl start serial-getty@ttyS0.service' def mh_z19(): ser = serial.Serial(serial_dev, baudrate=9600, bytesize=serial.EIGHTBITS, parity=serial.PARITY_NONE, stopbits=serial.STOPBITS_ONE, timeout=1.0) while 1: s=ser.read(9) result=ser.write("\xff\x01\x86\x00\x00\x00\x00\x00\x79") s=ser.read(9) print(s) if len(s) >= 4 and s[0] == "\xff" and s[1] == "\x86": return {'co2': ord(s[2])*256 + ord(s[3])} break def read(): p = subprocess.call(stop_getty, stdout=subprocess.PIPE, shell=True) result = mh_z19() p = subprocess.call(start_getty, stdout=subprocess.PIPE, shell=True) if result is not None: return {'CO2': result["co2"]} if __name__ == '__main__': # value = mh_z19() # print "co2=", value["co2"] value = read() if value is not None: print "co2=", value["CO2"] else: print "None" Link to comment Share on other sites More sharing options...
Scandinav21 Posted April 9, 2020 Author Share Posted April 9, 2020 Sorry, my fault, wrong gpio used. Apologise. Link to comment Share on other sites More sharing options...
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