Beginners Guide¶
This is a detailed beginners guide to eems.
1. Preparation¶
Before you can read DS18B20 sensors with eems several preparations need to be done.
1.1 Hardware¶
This section is under maintenance, meanwhile please use common references provided by the world wide web.
1.2 Software¶
Following chapter provides information regarding necessary software preparations.
1.2.1 Installation¶
Before you can use eems, it needs to be installed. This can be done via pip or git.
Install via pip:
pip install eems
Install via git:
git clone https://github.com/enricoba/eems.git
cd eems/
python setup.py install
1.2.2 Check configurations¶
Before you can star monitoring, system configurations need to be made. Before changing anything, a check function can be called to verify if any configurations are already set. Therefore, you can type following command into your terminal:
eems check
Or run the check inside a python script:
import eems
# generate check-object to identify ds18b20 requirements
c = eems.Check()
# check if modules w1-therm and w1-gpio are set
c.w1_modules()
# check if dtoverlay=w1-gpio is set in config.txt
c.w1_config()
1.2.3 Prepare configurations¶
If the configuration check told you that something is missing (either modules or config.txt), the necessary preparations can be done by typing following command into your terminal:
sudo eems prepare
Or by calling the function inside a python script:
import eems
# generate check-object to identify ds18b20 requirements
c = eems.Check()
# prepare configurations
c.prepare()
Be aware that you need to call the command or the python script with sudo rights!
2. Usage¶
The two main functions of eems are read and monitor.
2.1 Read¶
The command read reads all connected DS18B20 sensors once. The outputs are written into the console. This command mainly serves for testing issues.
Command line:
eems read
Python script (Object Temp also can accept parameters described in chapter 2.2.x) to activate console output, use console=True:
import eems
# generate temp-object to read sensors
t = eems.Temp(console=True)
# Read all connected DS18B20 sensors once.
t.read()
2.2 Monitor¶
The command monitor reads all connected DS18B20 sensors in a defined interval over a certain duration. Additionally, optional parameters can be passed using command line.
Running monitor via the command line with an interval of 2 seconds and a maximum duration of 10 seconds:
eems monitor -i 2 -d 10
The same result can be achieved inside a python script:
import eems
# generate temp-object to read sensors
t = eems.Temp(console=True)
# Start reading DS18B20 sensors with an interval of 2s and a maximum
# duration of 10s
t.monitor(interval=2, duration=10)
Default interval is 60 seconds and default duration is infinity. monitor can be interrupted by pressing Ctrl-C at any time. If a duration is defined, monitor stops after the duration has passed.
2.2.1 Csv¶
The first option is csv. By activating, a csv file is created and all sensor measurements are written into the file.
Command line example:
eems monitor -i 2 -d 10 --csv
Python script example:
import eems
# generate temp-object to read sensors and write temperatures into csv file
t = eems.Temp(csv=True)
# Start reading DS18B20 sensors with an interval of 2s and a maximum
# duration of 10s
t.monitor(interval=2, duration=10)
2.2.2 Log¶
The second option is log. By activating, a log file is created and all outputs are written into it.
Command line example:
eems monitor -i 2 -d 10 --log
Python script example:
import eems
# generate temp-object to read sensors and writing outputs to log file
t = eems.Temp(log=True)
# Start reading DS18B20 sensors with an interval of 2s and a maximum
# duration of 10s
t.monitor(interval=2, duration=10)
2.2.3 Console¶
The third and last option is console. By activating, all outputs are written into the console/terminal similar to print.
Command line example:
eems monitor -i 2 -d 10 --console
Python script example:
import eems
# generate temp-object to read sensors and write to console
t = eems.Temp(console=True)
# Start reading DS18B20 sensors with an interval of 2s and a maximum
# duration of 10s
t.monitor(interval=2, duration=10)
2.3 Examples¶
Examples for daily use.
2.3.1 Background process¶
One easy way to establish an easy monitoring system is to call the console command as a background process. This is achieved by adding & at the end of the command. That scenario also perfectly links with using csv file exports and the log file.
Command line example:
eems monitor -i 2 -d 60 --csv --log &
Either monitor ends after the duration has passed or the process is killed manually. This can be achieved by using typing following command:
kill <pid>
Thereby, <pid> needs to be replaced with the process pid. You can find the pid in the console after calling monitor or inside the log file.