A TLC5940 sells for about $5. It is a SPI based device so it only requires 4 or 5 lines to interface to the arduino and like Mike said you can add more chips in the daisy chain configuration . The library for that chip is on the forum and each chip has 16 outputs . The command allow sequential or simultaneous operation and if you are driving servos as opposed to leds, the current draw would not be that great. If the purpose of the LA grid is to lift something slowly while keeping it level then you need the simultaneous mode.Here's a tutorial : http://tronixstuff.com/2013/10/21/tutorial-arduino-tlc5940-led-driver-ic/ Here's the library: http://playground.arduino.cc/Learning/TLC5940#.Uz_4tPldWa8
rhino + grasshopper and then firefly
The purpose of LAs in the grid is to lift a neoprene membrane.
You lost me here:Quoterhino + grasshopper and then firefly ? (no clue what that means
Servo city has mechanical parts that might be of interest for your project. I suggest you focus on developing one actuator first, then on the other parts of the project. Have you just put spacers under your membrane at various heights to see if the membrane shapes as you think it would? https://www.servocity.com/
So using 11 TLC5940 (one for each row) I can easily smiley-roll-sweat manage the z-coordinates by a proper rotation of the stepper motors. every TLC5490 use 11 outputs (0 to 10).