Raspberry sensor collector service

Description

Java service which runs on Raspberry PI and collects data from multiple sensors using PI4J library.

Includes Ansible playbook which can deploy application on Raspberry PI and configure Grafana dashboard for sensor metrics.

Tested on Raspberry PI 2 model B.

The result looks like this:

Author

• Bruno Hemar

Sensors

Following sensors are supported:

Temperature and humidity sensor (DHT11)

Motion sensor

Laser sensor

By default, application will read data from all sensors. If you don't have all sensors, disable missing ones through property file (application.yml)

Connecting sensors with Raspberry PI

If you are not familiar with GPIO pin numbering, check documentation.

Connect signal sensor pins with following Raspberry GPIO pins:

Sensor	Raspberry GPIO pin
DHT11 Temperature & humidity sensor	7
Laser	2
Motion	29

GPIO signal pins can be changed in application.yml property file.

Building the project and deploying on Raspberry PI

Prerequisites

Building the project

• Maven 3
• Java 11 JDK

Running the application on Raspberry PI

• Java 11 JRE installed (included in Ansible playbook)
• wiringpi library installed (included in Ansible playbook)

Build the project

git clone https://github.com/bhemar/raspberry-sensor-collector.git
cd sensor-collector-service
mvn clean install

Deploy on Raspberry manually (without Ansible)

"Target" folder will contain executable jar "sensor-collector-service-1.0.0-SNAPSHOT.jar". Copy jar on Raspberry PI and run it:

cd target
scp sensor-collector-service-1.0.0-SNAPSHOT.jar pi@192.168.0.20:/tmp/
ssh pi@192.168.0.20
java -Dpi4j.debug -Dpi4j.linking=dynamic -jar /tmp/sensor-collector-service-1.0.0-SNAPSHOT.jar

Replace 192.168.0.20 with your Raspberry IP address. Of course, you should not use /tmp directory for jar location, this is just an example.

Deploy on Raspberry automatically (using Ansible)

If you have Ansible installed, you can deploy application on Raspberry PI and run it with a single command.

Before running Ansible playbook, check sensor_collector_service_jar_location variable in:

• ansible/sensor_collector_service/roles/sensor-collector-service/defaults/main.yml

Default is ~/IdeaProjects/sensor-collector-service/target

Run Ansible playbook:

cd ansible/sensor_collector_service/
ansible-playbook raspberry.yml -i hosts -u pi -k -K --tags "sensor-collector-service" -D

Enter your Raspberry password.

Endpoints

The metrics are exposed in Prometheus format:

http://raspberry-pi:9111/actuator/prometheus

Control laser sensor:

http://raspberry-pi:9111/laser/toggle
http://raspberry-pi:9111/laser/blink

Scrape metrics using Prometheus

Add job in prometheus.yml:

scrape_configs:

  - job_name: 'sensor-collector-service'
    metrics_path: '/actuator/prometheus'
    static_configs:
      - targets: ['raspberry-pi:9111']

Create dashboard for sensor metrics using Ansible

Preconditions:

• Grafana 5.0 or higher
• Dashboard provisioning enabled in /etc/grafana/provisioning/dashboards/

Run Ansible playbook with grafana tag:

cd ansible/sensor_collector_service/
ansible-playbook raspberry.yml -i hosts -u pi -k -K --tags "grafana"

Find Raspberry sensors dashboard in Grafana.