Solution that uses MQTT for connecting your washing machine when the light price is below a limit.
This system is based in three main modules:
- Two Node-Red flows:
- Light prices parser and publisher: every hour, this flow requests the current light price to the Red Electrica Española API and publishes it to the topic currentLightPrice.
- Washing machine simulator: This flow contains a node subscribed to the turnWashingMachineOn topic. When a message is received, the flow publishes a "ON" message to the washingMachineStatus topic. In parallel, it waits for a certain amount of time (simulating a washing cycle) and publishes an "OFF" message to the washingMachineStatus topic.
- Android App: this simple application lets the user choose the maximum amount desired to pay for the light (in €/MWh). By using the Paho MQTT Client library, it subscribes to the currentLightPrice topic. When a message is received, if the price is below the user's maximum and the user has enabled the option "Automatically turn washing machine on", the application will publish a message to the turnWashingMachineOn topic. The application is also subscribed to the washingMachineStatus topic, so that washing machine is not turned on if it is already working.
- Mosquitto MQTT broker: During the development of this system, the Mosquitto MQTT broker was deployed in a local machine
