pin board 2012

i am looking for a device to be made i have tried to do a few ways so far i tried with solenoid and coils. I have not been able to get it done due to cost. i need to have have a board of 400 pins that look a bit like a pin art toy. (they are arranged like a a grid 20 by 20) moved automatically I wish to be able to move some or all of the pins up or down at the same time and then the pins to stay in place I have tried to replace the pins with linear actuators but the cost sky rockets as each actuator costs 15 - 50 dollar x 400 =6k 30k So i need a cheap way to move the pins the cheapest way i can think of is to have a mechanical flick switch on the pin moving it up 1 mm at a time and another moving it down 1 mm at a time. by a device under the board . another is use a crayola twistable with the crayon replaced by a plastic bar and a plastic motor at the bottom with 10 spins should fully extend the bar. another is to have 3 tubes one inside other with middle one has magnet and insulation. Inner and outer have copper coils opposing each other seperated by insulation elec applied to inner coil pushes up middle tube and elec applied to outer tube puses down plastic tube by varing the power between both you can vary height of tube. I am sure there are other ways i am very open to otherways the target price of this board will be about 2k The pins will rise 100mm above the board and the board will be 200mm by 200mm ideally i would like less space between the pins. the pins should be square and between 9mm and 6mm wide. There is minimal load on the pins the board will need to be computer controlled with a simple interface where each pin can be numbered and each pin can be instructed to go to the required height. Every few seconds the board will be given a new set of heights for the pins to go to this should only take a few seconds. I am open to ways the pins can be moved but i will need a workable approach before i award the project. i will need six of these boards to be made so all can be controlled by the same computer at the same time.