Started data collection just hang it with a thin wire from ground and send back with some sharing. Collect data while sleeping and share in morning. If we have enough data, lets shame the other planets. See ligo upgraded silicon techology as a time pass and I used that to sense exactly what they did. Untested but yeah.
The phone is mounted on a scale with a hole at the edge. The app counts the number of oscillations and time period and hence calculates g. Enter the number of oscillations you want, the length and then press start and make the setup oscillate. It will give you the g value after the oscillations.
Keep phone vertical and press measure to get accelerometer y value (should be g) for comparision.