Imagine one hot and humid day in summer. Would you expect your air-con at home has already been cooling down the air so that you feel refreshed on arrival? It would be perfect if I can turn on the air-con just 10 minutes before home! Are you to die for it? What if I can connect my air-con with Raspberry PI that runs a serverless application, which is triggered by a public cloud application? It sounds so sweet! But... life is not that easy. I'd like to share my hard learning experiences while setting up this home automation system, using Raspberry PI, Azure Functions, Power Automate and Power Apps.