Crazy idea involving hundreds of LEDs

[Dave Flowerday]

Originally Posted by Qbranch

Remember to put resistors in series with your leds or you'll easily go over the 2.5mA per line drive current.

2.5mA is likely not going to cut it. We typically supply 10mA to LEDs in our projects, and that is acceptable but usually not super-bright, and this is for regular status LEDs that are not multiplexed. When you multiplex them, they're only on for a fraction of the time, making them appear even dimmer than usual.