Code to read and save temperature from ds18b20 temperature sensors with Arduino and python

Arduino code is adapted from:

• Rui Santos, https://randomnerdtutorials.com

See image here for wiring: https://i0.wp.com/randomnerdtutorials.com/wp-content/uploads/2019/07/ds18b20_arduino_multiple.png?w=1460&quality=100&strip=all&ssl=1

To run:

1. Follow steps at https://randomnerdtutorials.com/guide-for-ds18b20-temperature-sensor-with-arduino/ to install OneWire and Dallas Temperature libraries in the Arduino IDE
2. Compile and upload code to the arduino. Set the correct port if not connected at '/dev/ttyUSB0'. The default wait time between measurements is 10 seconds - adjust this as needed
3. Install this package (pulls in pyserial):

pip install -e .

Note: do not run pip install serial — that is an unrelated, abandoned package. The correct dependency is pyserial (which is what pip install -e . installs), and it is imported in Python as import serial.

4. Run the python code to log data. It will be saved as a .csv in the folder 'data':

python read_and_save_serial_temperaturedata.py

The python code starts a new csv file each day, and appends to current files so they can be viewed as the code is running.

Running as a systemd service (Linux)

To run the logger as a long-lived background process that auto-restarts on crash and on boot, install it as a systemd unit.

1. Create the unit file at /etc/systemd/system/bb-templogger.service:

[Unit]
Description=BeesBook Temperature Logger
After=network.target

[Service]
Type=simple
User=beesbook
WorkingDirectory=/home/beesbook/bb2026/bb_temperatureloggers
ExecStart=/home/beesbook/anaconda3/envs/beesbook/bin/python read_and_save_serial_temperaturedata.py
Restart=always
RestartSec=5
Environment=PYTHONUNBUFFERED=1

[Install]
WantedBy=multi-user.target

Adjust User, WorkingDirectory, and ExecStart to match your machine. ExecStart must be the absolute path to the python interpreter inside your conda env — find it by activating the env and running which python. systemd does not load your shell's PATH, so plain python will not work.

2. Enable and start the service:

sudo systemctl daemon-reload
sudo systemctl enable bb-templogger.service
sudo systemctl start bb-templogger.service

3. Check status and logs:

sudo systemctl status bb-templogger.service
sudo journalctl -u bb-templogger.service -f

Gotchas

• Serial port permissions: if /dev/ttyUSB0 is owned by group dialout, add the service user to that group so the script can open the port:

  sudo usermod -a -G dialout beesbook
  

  Reboot or log out/in for the group change to take effect.
• Conda env python path: point ExecStart directly at the env's python binary (e.g. /home/beesbook/anaconda3/envs/beesbook/bin/python). Do not try to conda activate from the unit file.