Temperatures to InfluxDB with Grafana Visualisation on Raspberry Pi

Note

This recipe is outdated. There is a new 2.x version of InfluxDB which integrates a web interface and dashboard (Grafana is not necessary). See the documentation for the v2 InfluxDB2DataSink plugin for more information.

This recipe is for running on a Raspberry Pi. It will collect temperature readings from commonly available DS18B20 temperature sensors and log them in an InfluxDB database. Grafana is used display the data over a web interface.

Hardware Setup

Any Raspberry Pi should work, this was tested using a Raspberry Pi 3 running Raspbian Buster using a Linux 4.19 kernel.

The DS18B20 temperature sensors require a 4.7 kΩ pullup resistor connected between the VCC and DATA lines. Some integrated modules already include the resistor. Connect the VCC to the RPi GPIO 3.3 V (pin 1), GND to ground (pin 6), and DATA to pin 7.

The 1-Wire bus on the RPi is not enabled by default. The easiest way to enable it is to run sudo raspi-config and select 1-Wire from the Interfacing Options. A reboot will be required. After the restart, check the sensor is detected with ls /sys/bus/w1/devices, which should list one or more devices starting with 28- and then a hex serial number. A reading can be obtained by running cat /sys/bus/w1/devices/28-xxxxxxxxxxxx/w1_slave, where xxxxxxxxxxxx is the serial number of the sensor. The response should include something like t=22062, where 22062 indicates 22.062 ℃.

The standard Linux libsensors is able to read the temperatures from attached probes:

sudo apt install libsensors5 lm-sensors
pip3 install --user PySensors

and can be read by running sensors.

Software Setup

InfluxDB

Add InfluxDB repository to apt sources (change buster to match your raspbian version):

wget -qO- https://repos.influxdata.com/influxdb.key | sudo apt-key add -
echo "deb https://repos.influxdata.com/debian buster stable" | sudo tee /etc/apt/sources.list.d/influxdb.list

Install InfluxDB, python plugin module, and start the systemd service:

sudo apt-get update
sudo apt-get install influxdb
pip3 install --user influxdb
sudo systemctl enable --now influxdb.service

The default configuration is probably OK, but can be changed by editing /etc/influxdb/influxdb.conf. The database service will be operating on port 8086.

Create a database for datalogd to store its data:

influx
create database datalogd
exit

Grafana

Follow instructions on the Grafana website to get latest version for your Raspberry Pi (eg. ARMv7). As of writing, for the Raspberry Pi 3 this is:

The Grafana server should be serving web pages from port 3000, so log into your RPi with a web browser and check that it is working (eg. visit http://ip_of_your_pi:3000).

Recipe

The connection graph can be configured using most defaults as:

recipes/rpi_temperature_influxdb.config

[datalogd]
connection_graph =
  digraph {
    a [class=LibSensorsDataSource];
    f [class=KeyValDataFilter, key="type", val="temperature"];
    s [class=InfluxDBDataSink];
    a -> f -> s;
  }

If you have changed the database configuration, such as usernames or passwords, then these must be set in the attruibutes for the InfluxDBDataSink node.

Visualisation

Log into your Grafana server (eg. http://ip_of_your_pi:3000. Configure an InfluxDB data source, using all default parameters. Configure a Grafana Dashboard as pictured: