TpSol is a free Android application developed by Yvon Massé in the Lifestyle category. Its main function is to provide the solar time according to the legal time and GPS location. However, it offers much more than that. It also supplies the equation of time and solar declination, indicates the azimuth and altitude of the Sun, and draws the shadow of the Sun on a sundial. The sundial can be drawn based on the orientation of the smartphone or tablet, and TpSol uses a magnetic sensor that needs calibration. The calibration process involves turning the device on the three axes for about 10 seconds per axis to ensure accurate computation and supply of the sundial orientation parameters. It should be noted that the accuracy is not better than some degrees.