rpi-sensehat_mqtt

Introduction

The files here create a service on the Raspberry Pi that works with the SenseHAT from the astro-pi project and streams its data over MQTT.

This service works on all the Raspberry Pi flavors, as long as they support the SenseHAT.

Folder structure

The files are here structured in this way:

• rpi_sensehat_mqtt.py python script to read the sensors and publish over MQTT
• rpi_sensehat_mqtt.logrotate configuration for logrotate to rotate the log file of this script
• rpi_sensehat_mqtt.env file to define the environmental variables used while running the background service
• rpi_sensehat_mqtt.service file to run the background service
• setconfiguration.sh script to configure the system and properly propagate the files in the right folders

How-to

The main python script rpi_sensehat_mqtt.py does the following operations when it runs:

• Reads sensor data
• Creates the MQTT message
• Publish it on the broker

The script logs its operations in the file /var/log/rpi_broadcaster/rpi_sensehat_mqtt.log.

The script requires a configuration through environmental variables defined in the rpi_sensehat_mqtt.env file. The available configuration parameters are:

• RPI_SENSEHAT_MQTT_LOGLEVEL="<desired loglevel>" the desired log level to be used in the log, as defined by the python library
• RPI_SENSEHAT_MQTT_CYCLE=<desired timecycle> the desired time cycle
• RPI_SENSEHAT_MQTT_LOCATION="<desired location>" to set the location in the message
• RPI_SENSEHAT_MQTT_BROKER="protocol://address:port" endpoint of the broker
• RPI_SENSEHAT_MQTT_TOPIC_PREFIX="<desired prefix>" to set the prefix for all the topics (default sensehat): readings is used for the readings and commands to process input commands
• RPI_SENSEHAT_MQTT_MEASUREMENT="<desired measurement>" measurement name
• RPI_SENSEHAT_MQTT_WELCOME="<desired welcome message>" welcome message at startup

Deploy

In order to deploy the configuration, you need to do the following steps

1. Run the file zip.bat
2. Transfer the zip file rpideploy_*.zip to the desired target machine
3. On the target machine, extract the zip file content
4. run the following command

   <sudo> bash ./setconfiguration.sh
   

After this has been successfully executed the new service is already running, and it can be managed using

<sudo> systemctl <command> rpi_sensehat_mqtt.service