phyphox for iPhone
Many of us use our iPhones without thinking about what else can be done with their sensors. phyphox for iPhone is one of many apps you can pick up to experiment with your phone. It gives you access to your phone’s sensors, so you can try new things and export raw data.
You can remote control your experiments through a web interface from your PC that happens to be on the same network as your phone. It supports magnetometer, gyroscope, pressure, GPS, proximity, and other phone sensors.