Hey, I am a beginner to python and circuts in general.

My issue is i want to use the IO ports of the expander pi to read the DS18B20. I found a tourtorial for the PI's GPIO ports that worked.

http://www.circuitbasics.com/raspberry-pi-ds18b20-temperature-sensor-tutorial/

But i cannot see what i have to change, to get it to use the IO ports instead.

Code from the tutorial:

import os
import glob
import time

os.system('modprobe w1-gpio')
os.system('modprobe w1-therm')

base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'

def read_temp_raw():
f = open(device_file, 'r')
lines = f.readlines()
f.close()
return lines

def read_temp():
lines = read_temp_raw()
while lines[0].strip()[-3:] != 'YES':
time.sleep(0.2)
lines = read_temp_raw()
equals_pos = lines[1].find('t=')
if equals_pos != -1:
temp_string = lines[1][equals_pos+2:]
temp_c = float(temp_string) / 1000.0
return temp_c

while True:
print(read_temp())
time.sleep(1)



And the code i tried to write:

#!/usr/bin/env python

import time

#Imports the ExpanderPi's IO port libary
try:
import ExpanderPi
except ImportError:
print("Failed to import ExpanderPi from python system path")
print("Importing from parent folder instead")
try:
import sys
sys.path.append('..')
import ExpanderPi
except ImportError:
raise ImportError(
"Failed to import library from parent folder")


SleepTimeH = 2 #delay for the program before continueing

#Activates the IO port 0 (pin 1-8) and activates the relay
iobus = ExpanderPi.IO()

iobus.set_port_direction(0, 255)


while True:
iobus.read_pin(3)
print(iobus.read_pin(3))
time.sleep(SleepTimeH)

I know my code just prints the reading from IO port. Which is 0 or 1

The math is easy to implement, but I cant get the right numbers out.

Hi

Unfortunately due to the way the 1 Wire protocol works the IO port on the Expander Pi is not suitable for communicating with a DS8B20 sensor. What you will need is a dedicated 1 Wire interface like our 1 Wire Pi Plus.

Hi Andrew

I think, I will just use the GPIO ports instead, since I already have some working code. Just need to expand it for more sensors and writing to a text file :)

Thanks for the fast reply.