For my 8th grade project, I created an Android app that uses machine learning to recognize sitting, standing, walking, and running in real time. I collected data from 10 people and extracted 33 features over a large array of window sizes. After that, I calculated the best algorithm, window size, and parameters using inner/outer cross-validation. My app displayed the current activity and tracked them over time. On top of that, I also added reminders to help people follow the 20-20-20 rule. This rule states that if you are looking at something close to your face (reading or using a computer), you should look at something 20 ft away for 20 seconds, every 20 minutes.
The python code is on GitHub at: github.com/KaviMD/8th-Grade-Project-Code
The AWARE plugin is on GitHub at: https://github.com/KaviMD/aware-plugin-machine-learning
This is my project presentation: https://www.youtube.com/channel/UCjlN_t-rUSomjJB1yBj34Bg