This is an automatic laser cat toy. It is enough to plug the USB cable into the power bank and place the toy on any hill, for example, a closet.
The servo model was designed in such a way as to have high reliability and fast assembly, as well as short printing time for 3D models.
For assembly, you need one Arduino Nano, two SG90 drives and a laser (module or laser from a laser pointer).
Any diode will do, it can be removed from any broken equipment. But, if you do not plan to flash the Arduino after assembly, then the diode can be omitted.
The diagram does not indicate a current-limiting resistor for the laser, it is assumed that the resistor is already installed on the laser itself.
Assembly
Print all models and assemble in stages as shown in the photos.