This is a project for an app which should simulate a sensor on an Android device.

• It can be also a “full featured” MQTT Client. There is not really many MQTT clients for Android (I know only MyMQTT).
  • unfortunately it seems to be not true…
    • Mqtt Dashboard seems to have this functionality too

Also it can be an Android replacement for mosquitto_pub (or later also for mosquitto_sub)

Key words:

• MQTT client data generator
• MQTT test data generator

IoT platforms to publish on them:

• OpenRemote
• ThingsBoard
  • https://thingsboard.io/docs/reference/mqtt-api/
• Node-RED
• OpenHAB
• Home Assistant

Citation from https://blogs.oracle.com/javamagazine/post/java-mqtt-iot-message-queuing :

There are quite a few MQTT brokers available under varying license models. Additionally, there are cloud services that support MQTT integration, such as Oracle Internet of Things Production Monitoring Cloud Service and Oracle Internet of Things Cloud Service.

The following are a few open source MQTT implementations:

• Eclipse Mosquitto 
• ActiveMQ MQTT
• Paho
• RabbitMQ

• MyMQTT - MQTT client for Android
• Mqtt Dashboard - allows both: configuration of existing IoT devices and “free” publishing to the topics (⇒ sending arbitrary data from the client)

• Tutorial: Connect your MQTT Client - from OpenRemote wiki

• How To Use MQTT in Java
• MqttExamples - a useful examples from Cumulocity
  • especially interesting:
    • working with certificates

• mosquitto_pub man page
• mosquitto_sub man page