A simple toothbrush robot which is very simple to make. Add a vibration motor, LR44 battery, toothbrush head and you have a perfect toy for kids.

BOM: 

• LR44 1.5V battery (e.g. this one)
• Mini vibration motor 10x2,7mm - 3V (e.g. this one)
• toothbrush head (ideally should be flat on both sides)
• small piece of ductape

Printing: better to print with PETG (PLA works as well, but could break during inserting the battery).

Assembly:

• glue the body on a toothbrush (double-sided tape, CA glue..)
• shorten the wires
• install the motor (usually has own glue preinstalled)
• put the negative wire through the hole (as in the image)
• insert the battery
• use a ductape as a power switch