Sending Temperature from RPI or OrangePI with MQTT and Mosquitto

So say you want to have temperature from your RPI devices shown on your MQTT dashboard.

Below are the steps to do it:

Install Mosquitto client

sudo apt-get install mosquitto-clients

Create bash script to calculate and send temperature

Google or just list folder thermal (see below) to find what temp sensors you have on the machine.

#!/usr/bin/env bash

TEMPERATURE_BIG=$(cat /sys/class/thermal/thermal_zone1/temp)
TEMPERATURE=$(expr $TEMPERATURE_BIG / 1000)

mosquitto_pub -d -h mosquitto_host -u user_name -P password -t topic/topic -m ${TEMPERATURE} >&2

Now is a good time to test if scripts works and check MQTT queue for messages.

Create service inside /etc/systemd/system/publish_temp.service

[Unit]
Description=Publish temperature to MQ service

[Service]
Type=simple
User=pi
WorkingDirectory=/opt
ExecStart=/opt/publish_temp.sh

Create timer inside /etc/systemd/system/publish_temp.timer

[Unit]
Description=Execute task every minute

[Timer]
OnBootSec=1min
OnUnitActiveSec=1min 

[Install]
WantedBy=multi-user.target

This script will send a message every minute within one minute of boot.

Validate that your messages are being delivered

Use any client (I use mqtt-spy) to connect to Mosquitto server and listen to this topic.

Profit!