It's okay to buy a Raspberry Pi 3 for study and interest, but I don't have time to touch it, but I have more and more things I want to do. So, I will summarize it as a memorandum on this page. Such an article.
--Install temperature sensors (temperature and humidity?) In 4 places in your room + 1 place outside the window, measure the temperature at regular intervals, and store logs. Finally, it is displayed as a graph on a spreadsheet or web browser.
reference Output the data detected by the sensor of Raspberry Pi to the text log in Python --Qiita Attach a CO2 sensor to the room and take a log --Qiita How to set log rotation --Qiita Measure the temperature with Raspberry Pi and take a log-from WIC
--Using infrared LED and lighting with remote control reception, you can turn on and off the room lighting by voice recognition or instructions from twitter.
reference Making an infrared remote control with Raspberry Pi Zero-Qiita Making an infrared remote control with Raspberry Pi 3-What is it Linking Raspberry Pi and Twitter (Twitter) --Raspberry Π Information from Raspberry Pi to Twitter! (1) Twitter API | Device Plus --Devapla