I have forgotten to say the current board size is 11"x8.5", and the color flaps is about 3" long with red and blue flaps crossed diagonally in the center of a 3x3 squares.
This needs quite large LCD which is in fact no less current than a single LED enclosed inside a same color enhancing plastic cover, and the cost of such large LCD is inhibitive.
There seems only another choice to rotate the color flaps by an electromechanical method now, I'm investigating if an affordable method can be found besides motors control.
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I have forgotten to tell the board is 11"x8.5" in size, with this size the LCD cost is inhibitive.
So it seems only 2 choices now:
1. Color LED enclosed in same color plastic cover which tend to enhance the same color, and bundle together with a large rechargeable battery with high voltage such as the 9v battery used in many multimeters, and bundle a charger circuit or even a charger together like how the mobile phone is sold.
The current consumption will be some tens ma but with a 9v 1000mah battery it can still last some hundreds hours, it's still OK for mist users.
2. Some electromechanical method to rotate the color flaps, by now I have not thought of any affordable solution, but motor control is an obvious solution though quite inhibitively expensive.