Suitable actuator for tiny lock

I have been looking into different actuators to operate a bolt in a small lock design. My first thought was to use a solenoid but even the smallest ones are simply too big. It seems that the smallest actuator on the market are piezo squiggle motors at around 1.5x1.5x6mm.

Does anyone have any recommendations in terms of compact low power consumption actuators?

How far, how fast, how much force, how much power available?

It's not that hard to wind your own solenoid with thin "magnet wire." You can make it square to fit the 1.5x1.5mm space if necessary. In fact, you're talking about something so small, that many relays are bigger than this. Find a mechanical relay of about the right size and pull it apart to extract the solenoid and magnet.

Attach a lever to a vibrator motor and apply a very short pulse. As it turns it can act as a rotary solenoid.


You can get ~7mm stepper motors (auto-focus motors for camera lenses is what they are
designed for I think) from eBay, but they need a lot of gearing down to get significant force.
They are quick though, 0 to 2400rpm without ramping is feasible in my experience. They are
very fiddly to work with and the wiring pins are easy to break.

slotless RC helicopter DC motors are available in small sizes (16mmx7mm or so) but they
need even more gearing (rated at 40,000 rpm or so from 4V 2A…)

have you considered a small linear servo? like this one...

tiny stepper motor with a screw driving a linear slide

might do the trick.

Wow - that is small.

So how much torque does that thing have?

A box of ten of them costs six cents!

I totally forgot to ask if you needed a linear or rotary actuator.