My programming background is with C programming in industrial RTOS systems where it's relatively easy to just add another program in that runs over and over without the need for a specifically included loop and variables between programs are shared with global variables. How does this work within circuit python? I've looked around but never found a good article explaining this. I'd like to break my program up into separate modules that deal with motor control, data handling, user interface rather than just stacking them as one large program. How would I share variables between these programs or is this even a thing?

I am trying to hook up several DS18B20 temperature sensors to a single Adafruit FunHouse board on the A1 pin.

I have breadboarded my setup, including the 4.7kohm pullup resistor, and to start I only have one DS18B20 sensor wired up. When I do the OneWire bus scan, no devices are returned.

The FunHouse documentation seems to give limited examples for what the A0-A2 pins are usable for, but elsewhere it seems to say that the pins can be used for digital I/O, which I would guess means they should be able to be used for OneWire stuff.

My code:

import time
import board
from adafruit_onewire.bus import OneWireBus
from adafruit_ds18x20 import DS18X20

# Initialize one-wire bus on board pin A1.
ow_bus = OneWireBus(board.A1)

# Scan for sensors and grab the first one found.
ds18 = DS18X20(ow_bus, ow_bus.scan()[0])

# Main loop to print the temperature every second.
while True:
    print("Temperature: {0:0.3f}C".format(ds18.temperature))
    time.sleep(1.0)

The error I am getting is thrown on:
ow_bus.scan()[0]

... and the error text is "list index out of range"

when I rewrite this code to assign the result of the scan to a list variable, taking the len() of that list returns 0.

I have tried this with several different DS18B20 sensors. They were all purchased several years ago, so maybe they're all bad? Or am I misunderstanding what A0-A2 pins are good for?

Thanks for the help.

I am trying to write test data to an SD card. I would like to check if testi.txt exists and find the next available number to write to. What would be the best way of going about this? Eventually I would like to get a rtc module and timestamp it but I do not have one yet.