ds18b20

rpi code to read ds18b20 sensor(s) and save info to .csv and/or upload to other backends

It’s inteded to run on a raspberry pi You can connect several ds18b20 sensors in parallel and it will read all of them.

Setup

The details on how to make the sensors work on rpi can be found with google but the nano version is

• connect sensor plus to rpi 3.3v, ground to rpi ground and sensor data to rpi #4.
• activate 1-wire protocol
• run "sudo raspi-config" then select "3 interface options" -> "I7 1-wire" -> enable
• load 1wire modules
• echo w1-gpio |sudo tee -a /etc/modules-load.d/modules.conf
• echo w1-therm |sudo tee -a /etc/modules-load.d/modules.conf
• activate it
• sudo reboot

with some luck you can now see the temperature sensors with ls -l /sys/bus/w1/devices/ or to see the temperature: grep -s . /sys/bus/w1/devices/*/temperature Note that the temperature shown need to be divided with 1000 to get it in Celsius.

Program

The program is designed to read all sensors found and save the data do multiple destinations. Some help can be received weith ./load_temp.py --help If the program is started without any config file or parameters a default config file is created as log_temp.ini.

The .ini file contains config information for the different way to save the temp. By default all are disabled ("enabled=false"). Each section contains what's required for that to destination to work. Things like username, password, hostname, database and so on. The sections are config, sensors, mqtt, db and influx.

config

• max_log_time: The longest time between logs, default=60
• max_list_length: To detect faster temperature changes it keep a list of the last few measurements and look for diff between lowest and highest number. The default length of that list is 10
• min_time_between_reads: minimum seconds between reads. Note that if it is several sensors it may take longer than this but it will never read faster. Default = 10
• min_temp_diff: It will look at the diff between lowest and highest temp in the list and if the diff is more than this it is logged. Default=0.5

sensors

You may want to have some kind of more descriptive label than the sensor serial number. Here you define the label you want for each serial number.

mqtt/db/influx

Info on how to connect to the different destinations. For details see the example config file or source code.