Build the circuit

To build the circuit you'll need a good soldering iron and a few readily available electronic components: a mosfet driver module, a DC motor and a 12V power source.

This is the most common mosfet module you can find in online stores:

 

It allows the Arduino to drive the motor. Follow this schematic to connect it:

The module can be used as it is, but I strongly recommend to add a schottky diode and a 100pF ceramic capacitor in parallel with the output to protect the Mosfet:

(Be sure the diode is in the right direction)

For the motor, anything with more than 20g*cm torque is fine. Be sure the shaft is at least 1cm long.
If you're in doubt, the ubiquitous FC-280PC/SC is a good choice for its high torque and low cost:

You can use an 8 cell AA battery holder as a power source:

If you don't like to waste batteries, any 12V / 2A power supply adapter would work as well.

Follow the schematic, when everything is connected, test the circuit using the Cock Hero Machine software:

 

Mirror: https://odysee.com/@CHMachine/build_the_circuit

Last step: build the vibrator.