help designing tiny solenoids

Hi everyone!..
I m trying to find a very tiny solenoid or such actuators with which I can implement gear shifting for different movements of fingers inside a robotic hand.

I tried hard but what i m getting is either over sized or over powered!. and over priced too ,so i dont think il get it anywhere..

If its possible to diy them..can someone guide me in designing tiny solenoids with following specs:(many required details may be missing but this is all i know for now)

Max 5V dc pulse actuation (no permanent magnets)
Linear movement max 5mm & min 3mm
Physical size can be as small as possible but
max overall thickness 5mm
Max overall height 15mm.

Any directions, guides, books tutorials is welcomed...pls help.

I m trying to find a very tiny solenoid or such actuators with which I can implement gear shifting for different movements of fingers inside a robotic hand.

Have you got pictures or links to show what that is all about?

I don't understand what you mean by "gear shifting".

For something this small, may I suggest turning small vibrator motors into linear actuators instead? Or if you need more speed, try using an offset cam to move the gears.

Depending on your gearbox design, you might even be able to use just one linear servo for all gear shifts.

If you have ever taken apart the disk drive from an older laptop, you will fond that little solenoids are used to pop out the disk tray. They are somewhat similar to these:

I think a micro linear servo may work well instead of a solenoid. Something like:
http://www.amazon.com/Spektrum-1-5-Gram-Linear-Servo/dp/B001U3MHS4/ref=sr_1_3?ie=UTF8&qid=1365135870&sr=8-3&keywords=micro+linear+servo

They are both good ideas. Solenoids are fast but not often powerful. The actuators are stronger but may be slower.