Da Vinci challenged the public with a number of perpetual motion machines and he tricked many people with them. In reality, the sum of distances and weights of all the moving parts is zero. No energy will be generated. Da Vincy did not have acces to geared micro dc motors. He surely would have used them to make his machines even more convincing.
A microswich is actuated when the unit is placed on the table. So, like in the video, lift the unit and place the four (17mm) marbles. Act as if you have to hold the wheel until you place the unit carefully on a flat surface. At that moment let the wheel go and it starts rotating. Wheel rotates in the wrong direction? Just swap the motor wires. A 6 volt motor runs very wel on 3 volts (2 AA batteries). If the motor runs too fast, put a resistor of about 330 Ohms in series with the motor. The microswitch is kept in place by two M2 bolts. Tip: If marbles slip away between the strips (as seen in the video at the left side), heat the strips in hot water(about 90C) and bend them carefully towards each other. One millimeter is enough. https://youtu.be/wErkUeWKXRM Another da Vinci Thing: https://www.thingiverse.com/thing:2833419