A solenoid is sub-optimal for generating ongoing vibration. If the intent were to generate a single shock intermittently, then sure, a solenoid would be a good choice.

For mechanical vibrations (presumably for sensing by human touch), two options are popular:

1. Offset Weight motors, aka pager motors, vibration motors:

• These are available down to very small sizes, and very low current and voltage ratings, such as 1.5 Volts, 10 mA in 3mm x 3mm x 5 mm, surface mounted.
• Operating them from your circuit is simple, even trivial.
• Downside: Very precise start and stop timing is not feasible, and vibration frequency is not simple to modify.
• Mobile phones (and of course pagers in ancient times) typically use such motors for vibrating ring notification

2. Piezoelectric benders aka coin-type speakers:

• These exist in very small heights, down to under 0.5 mm, but diameter is usually 5 to 10 mm for effective output.
• Actuated by a haptic driver or haptic controller IC, or even an oscillator at desired vibration frequency, these are a little more complex to drive. Some such haptic piezo actuators require tens or even hundreds of volts, although at minuscule current. The haptic drivers typically generate the required voltages internally.
• Both vibration frequency and start/stop time can be controlled with great precision.
• Mobile phone haptic feedback, i.e. the mild buzzing sensation some mobiles offer to indicate the press of a key on a touch screen, for instance, typically use this mechanism.

A solenoid is sub-optimal for generating ongoing vibration. If the intent were to generate a single shock intermittently, then sure, a solenoid would be a good choice.

For mechanical vibrations (presumably for sensing by human touch), two options are popular:

1. Offset Weight motors, aka pager motors, vibration motors:

• These are available down to very small sizes, and very low current and voltage ratings, such as 1.5 Volts, 10 mA in 3mm x 3mm x 5 mm, surface mounted.
• Operating them from your circuit is simple, even trivial.
• Downside: Very precise start and stop timing is not feasible, and vibration frequency is not simple to modify.
• Mobile phones (and of course pagers in ancient times) typically use such motors for vibrating ring notification:
  
  _{(Source: eBay.com, Vibrating Micro Motor - 1 to 4.5 V - 13 mm x 7 mm)}

2. Piezoelectric benders aka coin-type speakers:

• These exist in very small heights, down to under 0.5 mm, but diameter is usually 5 to 10 mm for effective output.
• Actuated by a haptic driver or haptic controller IC, or even an oscillator at desired vibration frequency, these are a little more complex to drive. Some such haptic piezo actuators require tens or even hundreds of volts, although at minuscule current. The haptic drivers typically generate the required voltages internally.
• Both vibration frequency and start/stop time can be controlled with great precision.
• Mobile phone haptic feedback, i.e. the mild buzzing sensation some mobiles offer to indicate the press of a key on a touch screen, for instance, typically use this mechanism.
• For an example of a piezo haptic driver with an integrated voltage boost converter, see the Texas Instruments DRV8662.
  
  _{(Source: eBay.com, 12mm Piezo Disc)}