After Mosquitto server, ESP8266 nodes and Freeboard configuration
now we can proceed to use a Mqtt Client on an Android device.
In the Playstore various Mqtt applications are available
it is possible to monitor the sensor temperature and humidity, the devices status and send commands to the relay (Turn On, Turn Off, Status, Restart, Sleep) and to the sensor (Restart, Sleep, Status).
Here is a screenshot with some subcriber topic and publisher topics of our installation using MQTT Dashboard